DCS Foot-Powered Vibrating Table

Manufacturer
Development and Consulting Services
P.O. Box 8
Butwal
Nepal
Tel. [..977] 73-20391
Fax. [.. 977] 73 - 20465
e-mail: bhusan%dcs@umn.mos.com.np

Description

The DCS Foot-Powered Vibrating Table is a one-person operation screeding table, manufactured in Nepal since 1987. The vibrating surface and drive mechanism are mounted on an angle iron frame. Connected to this is a seat, which is adjustable to suit the tile maker's stature, so that he can sit comfortably at the table while making the tile. He rocks the two foot pedals back and forth at an easy speed, driving a bicycle wheel, which in turn drives an eccentric weight assembly beneath the aluminium vibrating surface at a speed of 2500 to 3000 rpm. Careful fitting of all nine sealed bearings ensures easy operation and long life for the machine. The screeding table has a one year guarantee.

The screeding frames for tiles (6 and 8 mm thick) are shaped to provide an "interlock" at the mitre - the diagonal mitre has been replaced by a dog-legged mitre. The frames also provide nib construction boxes for a wind proof fixing of all tiles. Experience shows that wind forces are sufficient to lift tiles, so all tiles are made with a lower fixing nib. A second nib may be made at the top for special conditions (top line of monoslope roofs, edges with long overhangs). When they are not needed, these nib boxes can be swung out of the screeding area (to leave it unobstructed for quick working) and positioned when needed.

The moulds are 535 mm long concrete elements fixed into galvanized sheet stacking frames, which also serve to protect the fresh tile from drying out during setting. DCS sells fitted moulds and frames with the screeding tables. This ensures that the moulds used are accurate and of good quality and allows the entrepreneur to start tile production immediately, so that he soon can produce a demonstration roof to show interested customers and begin to earn money without delay. He can, however, also buy a fibreglass mother mould, with which he can make his own moulds later (when he has sufficient experience), in order to replace broken moulds or increase his production capacity.

In addition to the screeding table and tile moulds, the following accessories are supplied:

· a set of batching boxes for fast measurement of cement and sand to correct proportions and workable batch size;

· a set of tile maker's scoops to enable correct batching of the wet mortar as tiles are made;

· a tile thickness gauge for checking finished tiles according to the standard;

· a batten gauge to aid quick and accurate roof building.

Entrepreneurs may purchase extra tools for quality checking:

· standard vessel to measure water for mixing;
· prism mould, loading jig and thickness gauge for checking mortar strength.

DCS also supplies sieves for screening sand and fine aggregate, shovels, trowels, pliers, tile stack covers, interface plastics etc.

Maintenance

The screeding table is maintenance free for up to 5 years, if cleaned regularly during tile making. The tile frame and screeding surface must be cleaned after each tile is screeded, in order to avoid distorting them. Bearings are protected by seals and cover plates. The bushes for the frame clamping arms and for the vibrating drive should be lubricated before the machine is stored for a period of no production, to avoid seizure from rust. The screeding surface mounting rubbers need replacing every year, as they absorb/damp vibration when they are perished. Replacement rubbers can be hand made from a scrap truck tyre; footwear repairers always have this type of rubber available.

Moulds need regular cleaning to avoid build-up of spilt mortar. Daily cleaning with a cloth or handful of fibre is quick and easy. Mortar left longer can be scraped off without fear of damage to the mould, as it has a hard surface.

Figure

Training

DCS selects prospective entrepreneurs from applicants for an 11-day training course in FCR/MCR. The training is held in Butwal and includes theory and practical sessions covering

· production (including raw material selection, quality checks),
· tile use (roof types, construction, tile fitting),
· entrepreneur motivation,
· marketing skills,
· case reports and a tour to an established tile producer,
· book-keeping,
· obtaining finance.

Operating the DCS Vibrating Table

Before production, the tile maker must adjust the seat to enable him to sit comfortably while working. Also the screeding surface must be levelled before beginning. A small backrest is provided to give the light support needed while operating the foot pedals and screeding the mortar. Pedalling is not heavy work for the operator's legs.

When the mortar has been batched and mixed, the operator sits at the table, places a plastic interface sheet on the screeding table, then clamps down the appropriate tile frame. Using the corresponding scoop, a measured lump of mixed mortar is placed on the screeding table, and then this is trowelled out to an even thickness within the tile frame, while generating the vibration by rocking the foot pedals back and forth. When the screed surface is smooth and level with the screeding frame, the nib on the lower tile end is made by swinging the nib construction box into place, filling it with mortar under vibration, and inserting a wire loop for fixing on the supporting roof batten. Depending on the roof design, some of the tiles will need a second nib on the upper end, for which another nib box is provided.

After the nibs are made, the plastic sheet with the screeded mortar is lifted onto the next empty mould. This mould is then moved to the stack of newly moulded tiles and the position of the screed on the mould is checked. It is covered with the next mould and screed, or a mould cover if it is at the top of the stack, to prevent the mortar from drying.

The tiles are removed from the moulds after about 24 hours and subsequently cured for 2 weeks in water tanks or vapour curing beds.

1. Placing mortar on the screeding surface

2. Spreading the mortar under vibration

3. Lifting the plastic sheet with the screeded mortar to place it on the mould

4. Detail of the bicycle wheel drive mechanism

5. Mould stack with fresh rooftile

A Simple Windproof Tile Fixing Method