Vertical Materials Handling Systems aka Dumbwaiters
Learning Objectives - After this course, you should be able to:
- Have a general knowledge of different vertical material handling systems and when to use them.
- Identify key design and planning criteria.
- Discuss the benefits of using vertical material handling systems.
Once a simple hoist mechanism, the dumbwaiter is now the smart, efficient, safe and economic solution for moving materials from one floor to another.
Since the late 18th century when Jefferson adopted the French custom of using several of them for dinner parties, the dumbwaiter has joined our lexicon. It has saved labor and efficiently solved the eternal challenge of moving objects from one floor to another. But dumbwaiters of the twenty first century are a far cry from those hand-crafted European devices. For one thing, Jefferson's dumbwaiters, while certainly silent, did not move. Different from the wine elevators he installed on both sides of Monticello's dining room fireplace that led directly to the wine cellar below, they were small free-standing tables whose several shelves held food, dishes and silver. Placed beside each guest, they replaced curious servants or slaves and were intended to encourage free and unrestricted conversation. Another difference is that today's dumbwaiter-despite its name-is smart, a significantly less costly alternative to the elevator, employs state of the art technology and promotes safety. While the elevator has generated a body of knowledge-it even has its own online museum-the dumbwaiter has been virtually ignored despite its long-time use in a multitude of building types.
Over the years, the dumbwaiter has lent its name to a group of products known as vertical materials handling systems-systems that have proven adaptable to any situation in which goods of any kind-but not people-are moved from floor to floor in multi-story buildings.
Promoting Economy, Safety and Efficient Use of Space
It "saves miles of steps for busy feet," announces a 121-page brochure from a former Chicago dumbwaiter manufacturer dated 1914. Inside are abundant photographs of virtually every major hotel, club, hospital, restaurant, department store and office in the country that had acquired one of its electrified systems. The company added the cogent argument that its system also saved money, "don't waste the valuable time of high priced help in running up and down stairs with goods." While the cost of help in 1914 must appear ludicrously low in today's dollars, the point is particularly relevant today. Dumbwaiters create payback efficiencies. Passenger elevators are not tied up with the transportation of materials and can therefore accomplish the purpose of moving people quickly and efficiently. Since they do not need to walk around or up and down stairs delivering materials along with obligatory pleasantries, employees are able to stay in their offices and their workstations. The calculation of a hypothetical situation makes a striking point. If ten employees whose average salary and benefits amount to $35 per hour make three 20-minute trips per day, the cost to their employee is $3,500 per week.
Safety is another benefit. With the appropriate choice of product, employees avoid dangerous misuse of equipment such as fork lifts and chain hoists. Employees pushing, pulling, carrying and lifting often cause accidents, falls, bumps and injuries. In addition to time lost through hours and days off, there are additional costs incurred in related paperwork, reports and possible litigation. The Bureau of Labor Statistics reports that in 2003, sprains and strains accounted for 43 percent of injuries resulting in days away from work in the private sector- evidence that appropriate materials handling positively contributes to safety and welfare for all partiesDumbwaiters also save space and cost less than their alternatives. Depending upon configuration and the type of lift, initial total installed costs are approximately 40 percent to 60 percent less than that of a passenger or freight elevator. In terms of square footage of a building floor plan, they require 50 to 75 percent less than that taken up by an elevator. This translates into significant useful space that can be allocated to the original purpose of the building. They also have both a long life and-at 25 years-a long modernization cycle.