Sistem Conveyor yaitu sistem mekanis yang memilik tujuan
untuk memindahkan antar tempat(dari tempat satu ke tempat yang lain). Conveyor Seringkali
Dipakai Untuk Memindahkan Barang Oleh Perusahaan Besar.
Dilihat Dari Beberapa Sudut,
Conveyor Memiliki Nilai Ekonois Dalam Memindahkan barang, jika dibandingkan dengan truk. Conveyor
dapat menampung barang dengan jumlah besar dan terus berlanjut (continue) dari satu tempat ke
tempat lain. Perpindahan tempat tersebut harus mempunyai Tempat yang tetap untuk berhent, agar
nilai ekonomis Conveyor Terlihat begitu bermanfaat. Tentu Sistem ini Memiliki Kelemahan Juga.
Kelemahan sistem ini adalah tidak empunyai fleksibilitas saat lokasi barang yang dipindahkan
tidak tetap dan jumlah barang yang masuk tidak Terus Menerus(continue).
Conveyor Berkembang Menjadi eragai Jenis. Jenis-jenis conveyor tersebut antara lain Apron,
Flight, Pivot, Overhead, Loadpropelling, Car, Bucket, Screw, Roller, Vibrating, Pneumatic, dan
Hydraulic. Disini akan dibahas satu jenis conveyor yaitu Roller Conveyor.
Roller conveyor adalah sistem conveyor yang
penumpu utama barang yang dipindahkan adalah roller. Roller yang terdapat pada sistem ini berbeda
dengan roller pada conveyor jenis yang lain. Roller pada sistem ini didesain khusus agar cocok
dengan kondisi barang yang dipindahkan, misal roller diberi lapisan karet, lapisan anti karat,
dan lain sebagainya. Sedangkan roller pada sistem jenis yang lain didesain cocok untuk sabuk yang
FUNGSI DAN SPESIFIKASI ROLLER
Roller conveyor hanya bisa memindahkan barang yang berupa unit dan tidak bisa
memindahkan barang yang berbentuk bulk atau butiran. Unit yang bisa dipindahkan menggunakan
roller conveyor juga harus mempunyai dimensi tertentu dan berat tertentu agar bisa
ditransportasikan. Untuk memindahkan barang dalam bentuk bulk, bulk tersebut harus dikemas
terlebih dahulu dalam unit agar bisa ditransportasikan menggunakan sistem ini.
Spesifikasi roller conveyor juga harus disesuaikan dengan dimensi dan beban unit yang akan
ditransportasikan. Rancangan sistem roller conveyor harus mempu menerima beban maksimum yang
mungkin terjadi pada sistem conveyor. Selain itu, desain dimensi sistem juga harus
dipertimbangkan agar sesuai dengan dimensi unit yang akan ditransportasikan. Dalam beberapa kasus
dimensi unit yang lebih lebar dari dimensi lebar roller masih diperbolehkan.
antar roller disesuaikan dengan dimensi unit yang akan ditransportasikan. Diusahakan jarak antar
roller dibuat sedekat mungkin agar tumpuan beban semakin banyak. Selain itu, dimensi unit yang
ditranportasikan minimal harus ditumpu oleh 3 roller. Jika kurang dari 3 roller, maka unit
tersebut akan tersendat bahkan bisa jatuh keluar sistem tranportasi roller conveyor.
Kelebihan roller conveyor adalah bisa mentransformasikan pada kemiringan tertentu sehingga
conveyor bisa mentranportasikan barang dari satu tingkat ke tingkat yang lain. Selain itu, roller
conveyor juga bisa membelokkan jalur unit yang belokkannya sangat tajam. Hal tersebut bermanfaat
untuk daerah yang ruanganya terbatas.
Selain itu, roller
conveyor memmpunyai kemampuan untuk menggabungkan 2 jalur yang terpisah. Penggabungan 2 jalur
tersebut dapat dilakukan dengan berbagai metode seperti Y-Line dan accumulating roller
Mekanisme kerja roller conveyor
secara umum adalah sebagai berikut:
1.Motor penggerak memutar poros pada motor yang
telah terpasang sistem transmisi menuju drive roller.
2.Putaran poros pada motor
ditransmisikan ke drive roller melalui sistem transmisi yang telah dirancang khusus untuk sistem
3.Drive roller yang terpasang sistem transmisi tersebut ikut berputar
karena daya yang disalurkan oleh sistem transmisi.
4.Drive roller mentransmisikan
putaran roller ke roller lain dengan tranmisi rantai.
5.Antar roller diberi jalur
transmisi yang sama dengan perbandingan transmisi 1:1 sehingga putaran antar roller mempunyai
kecepatan yang sama.
6.Tranmisi antar roller tersebut diteruskan sampai ke roller paling
But an unusual assortment of players, including furniture makers, the Chinese government, Republicans from states with a large base of furniture manufacturing and even some Democrats who championed early regulatory efforts, have questioned the E.P.A. proposal. The sustained opposition has held sway, as the agency is now preparing to ease key testing requirements before it releases the landmark federal health standard.
The E.P.A.’s five-year effort to adopt this rule offers another example of how industry opposition can delay and hamper attempts by the federal government to issue regulations, even to control substances known to be harmful to human health.
Formaldehyde is a known carcinogen that can also cause respiratory ailments like asthma, but the potential of long-term exposure to cause cancers like myeloid leukemia is less well understood.
The E.P.A.’s decision would be the first time that the federal government has regulated formaldehyde inside most American homes.
“The stakes are high for public health,” said Tom Neltner, senior adviser for regulatory affairs at the National Center for Healthy Housing, who has closely monitored the debate over the rules. “What we can’t have here is an outcome that fails to confront the health threat we all know exists.”
The proposal would not ban formaldehyde — commonly used as an ingredient in wood glue in furniture and flooring — but it would impose rules that prevent dangerous levels of the chemical’s vapors from those products, and would set testing standards to ensure that products sold in the United States comply with those limits. The debate has sharpened in the face of growing concern about the safety of formaldehyde-treated flooring imported from Asia, especially China.
What is certain is that a lot of money is at stake: American companies sell billions of dollars’ worth of wood products each year that contain formaldehyde, and some argue that the proposed regulation would impose unfair costs and restrictions.
Determined to block the agency’s rule as proposed, these industry players have turned to the White House, members of Congress and top E.P.A. officials, pressing them to roll back the testing requirements in particular, calling them redundant and too expensive.
“There are potentially over a million manufacturing jobs that will be impacted if the proposed rule is finalized without changes,” wrote Bill Perdue, the chief lobbyist at the American Home Furnishings Alliance, a leading critic of the testing requirements in the proposed regulation, in one letter to the E.P.A.
Industry opposition helped create an odd alignment of forces working to thwart the rule. The White House moved to strike out key aspects of the proposal. Subsequent appeals for more changes were voiced by players as varied as Senator Barbara Boxer, Democrat of California, and Senator Roger Wicker, Republican of Mississippi, as well as furniture industry lobbyists.
Hurricane Katrina in 2005 helped ignite the public debate over formaldehyde, after the deadly storm destroyed or damaged hundreds of thousands of homes along the Gulf of Mexico, forcing families into temporary trailers provided by the Federal Emergency Management Agency.
The displaced storm victims quickly began reporting respiratory problems, burning eyes and other issues, and tests then confirmed high levels of formaldehyde fumes leaking into the air inside the trailers, which in many cases had been hastily constructed.
Public health advocates petitioned the E.P.A. to issue limits on formaldehyde in building materials and furniture used in homes, given that limits already existed for exposure in workplaces. But three years after the storm, only California had issued such limits.
Industry groups like the American Chemistry Council have repeatedly challenged the science linking formaldehyde to cancer, a position championed by David Vitter, the Republican senator from Louisiana, who is a major recipient of chemical industry campaign contributions, and whom environmental groups have mockingly nicknamed “Senator Formaldehyde.”
By 2010, public health advocates and some industry groups secured bipartisan support in Congress for legislation that ordered the E.P.A. to issue federal rules that largely mirrored California’s restrictions. At the time, concerns were rising over the growing number of lower-priced furniture imports from Asia that might include contaminated products, while also hurting sales of American-made products.
Maneuvering began almost immediately after the E.P.A. prepared draft rules to formally enact the new standards.
White House records show at least five meetings in mid-2012 with industry executives — kitchen cabinet makers, chemical manufacturers, furniture trade associations and their lobbyists, like Brock R. Landry, of the Venable law firm. These parties, along with Senator Vitter’s office, appealed to top administration officials, asking them to intervene to roll back the E.P.A. proposal.
The White House Office of Management and Budget, which reviews major federal regulations before they are adopted, apparently agreed. After the White House review, the E.P.A. “redlined” many of the estimates of the monetary benefits that would be gained by reductions in related health ailments, like asthma and fertility issues, documents reviewed by The New York Times show.
As a result, the estimated benefit of the proposed rule dropped to $48 million a year, from as much as $278 million a year. The much-reduced amount deeply weakened the agency’s justification for the sometimes costly new testing that would be required under the new rules, a federal official involved in the effort said.
“It’s a redlining blood bath,” said Lisa Heinzerling, a Georgetown University Law School professor and a former E.P.A. official, using the Washington phrase to describe when language is stricken from a proposed rule. “Almost the entire discussion of these potential benefits was excised.”
“That’s a huge difference,” said Luke Bolar, a spokesman for Mr. Vitter, of the reduced estimated financial benefits, saying the change was “clearly highlighting more mismanagement” at the E.P.A.
The review’s outcome galvanized opponents in the furniture industry. They then targeted a provision that mandated new testing of laminated wood, a cheaper alternative to hardwood. (The California standard on which the law was based did not require such testing.)
But E.P.A. scientists had concluded that these laminate products — millions of which are sold annually in the United States — posed a particular risk. They said that when thin layers of wood, also known as laminate or veneer, are added to furniture or flooring in the final stages of manufacturing, the resulting product can generate dangerous levels of fumes from often-used formaldehyde-based glues.
Industry executives, outraged by what they considered an unnecessary and financially burdensome level of testing, turned every lever within reach to get the requirement removed. It would be particularly onerous, they argued, for small manufacturers that would have to repeatedly interrupt their work to do expensive new testing. The E.P.A. estimated that the expanded requirements for laminate products would cost the furniture industry tens of millions of dollars annually, while the industry said that the proposed rule over all would cost its 7,000 American manufacturing facilities over $200 million each year.
“A lot of people don’t seem to appreciate what a lot of these requirements do to a small operation,” said Dick Titus, executive vice president of the Kitchen Cabinet Manufacturers Association, whose members are predominantly small businesses. “A 10-person shop, for example, just really isn’t equipped to handle that type of thing.”
Big industry players also weighed in. Executives from companies including La-Z-Boy, Hooker Furniture and Ashley Furniture all flew to Washington for a series of meetings with the offices of lawmakers including House Speaker John Boehner, Republican of Ohio, and about a dozen other lawmakers, asking several of them to sign a letter prepared by the industry to press the E.P.A. to back down, according to an industry report describing the lobbying visit.
The industry lobbyists also held their own meeting at E.P.A. headquarters, and they urged Jim Jones, who oversaw the rule-making process as the assistant administrator for the agency’s Office of Chemical Safety and Pollution Prevention, to visit a North Carolina furniture manufacturing plant. According to the trade group, Mr. Jones told them that the visit had “helped the agency shift its thinking” about the rules and how laminated products should be treated.
The resistance was particularly intense from lawmakers like Mr. Wicker of Mississippi, whose state is home to major manufacturing plants owned by Ashley Furniture Industries, the world’s largest furniture maker, and who is one of the biggest recipients in Congress of donations from the industry’s trade association. Asked if the political support played a role, a spokesman for Mr. Wicker replied: “Thousands of Mississippians depend on the furniture manufacturing industry for their livelihoods. Senator Wicker is committed to defending all Mississippians from government overreach.”
Individual companies like Ikea also intervened, as did the Chinese government, which claimed that the new rule would create a “great barrier” to the import of Chinese products because of higher costs.
Perhaps the most surprising objection came from Senator Boxer, of California, a longtime environmental advocate, whose office questioned why the E.P.A.’s rule went further than her home state’s in seeking testing on laminated products. “We did not advocate an outcome, other than safety,” her office said in a statement about why the senator raised concerns. “We said ‘Take a look to see if you have it right.’ ”
Safety advocates say that tighter restrictions — like the ones Ms. Boxer and Mr. Wicker, along with Representative Doris Matsui, a California Democrat, have questioned — are necessary, particularly for products coming from China, where items as varied as toys and Christmas lights have been found to violate American safety standards.
While Mr. Neltner, the environmental advocate who has been most involved in the review process, has been open to compromise, he has pressed the E.P.A. not to back down entirely, and to maintain a requirement that laminators verify that their products are safe.
An episode of CBS’s “60 Minutes” in March brought attention to the issue when it accused Lumber Liquidators, the discount flooring retailer, of selling laminate products with dangerous levels of formaldehyde. The company has disputed the show’s findings and test methods, maintaining that its products are safe.
“People think that just because Congress passed the legislation five years ago, the problem has been fixed,” said Becky Gillette, who then lived in coastal Mississippi, in the area hit by Hurricane Katrina, and was among the first to notice a pattern of complaints from people living in the trailers. “Real people’s faces and names come up in front of me when I think of the thousands of people who could get sick if this rule is not done right.”
An aide to Ms. Matsui rejected any suggestion that she was bending to industry pressure.
“From the beginning the public health has been our No. 1 concern,” said Kyle J. Victor, an aide to Ms. Matsui.
But further changes to the rule are likely, agency officials concede, as they say they are searching for a way to reduce the cost of complying with any final rule while maintaining public health goals. The question is just how radically the agency will revamp the testing requirement for laminated products — if it keeps it at all.
“It’s not a secret to anybody that is the most challenging issue,” said Mr. Jones, the E.P.A. official overseeing the process, adding that the health consequences from formaldehyde are real. “We have to reduce those exposures so that people can live healthy lives and not have to worry about being in their homes.”