Gadget 1: Table for Fabricating Cymbidium Export Boxes
Orchid boxes are manufactured as two (lid and base)
pre-formed cardboard plates (blanks) and are supplied in bundles of twenty-five
or thirty pieces. The boxes are
fabricated by folding the sides and ends along pressed grooves and stapling
each corner. Depending on the number of
boxes to be fabricated and the staff capability, various fabrication techniques
are used including hand, electric and pneumatic stapling equipment. If a significant number of boxes are to be
made then there is a large amount of wrist work involved in bending the sides
and ends and folding all of the corners.
When this work is allocated to a single person for a substantial period
it can be quite physically demanding leading to a drop in productivity over
time or even worst the risk of a repetitive strain injury (RSI). With this in mind a simple rotating table was
developed specifically for fabricating cymbidium boxes. The table is intended for manual operation
but further development to incorporate a pneumatic ram would be relatively
straight forward.
The table consists of a centrally mounted rotating arm
(carousel), a series of forming cradles which can be fitted onto the rotating
arm and an accompanying press-plate for each cradle. There are four forming cradles, one each for:
Standard Lid, Standard Base, Mini Lid and Mini Base. The forming cradles are made of 9 cm. by 2
cm. dressed timber (decking) with the internal dimensions of the lower section being slightly larger than the outside dimension
of the box part to be formed and the upper section being slightly larger still. On the top of the upper section there are four
small blocks to raise the end tabs. The
press-plates are slightly smaller than the size of the internal dimensions of the box part to be
formed and have a section cut out of each corner where the end tabs will go
once the box is formed.
To fabricate a box a pre-formed blank is placed on top of
the cradle, the press-plate is placed inside the box and pushed down
firmly. This action raises the ends and
the sides and presents the corners ready for stapling. The corners are stapled one at a time by
rotating the table. When all four
staples are in place the press-plate and the formed box are removed from the
cradle and the system is repeated for the next box.
To facilitate the correct placement of the
pre-formed plate on the cradle and to help the end tabs to seat properly, the
end tabs should be bent upwards first.
This can be done relatively easily for the whole bundle (i.e.
twenty-five to thirty pieces at a time).
The most suitable height for the table will depend on the
height of the most regular user. The
specifications for the prototype are:
- Height from floor to the top of the rotary arm is 84 cm. This is suitable for a short person.
- Length of the table is 98 cm.
- Width of the table 87 cm.
The table is made of 2x3 (inch) rough sawn timber. The bearing for the rotary arm is mounted,
using four “U” bolts, on two lengths of ¾ inch galvanised pipe. The bearing itself is from the mowing deck of
a ride-on mower.
For convenience a small shelf has been added to the rear of
the table to hold the press-plate while a new pre-formed blank is loaded onto
the cradle.
The above photo is a general view of the table with a forming cradle in position. In the foreground is a hearth brush which acts as a damper to slow the table down during rotation. The shelf for holding the press-plate when not in use is at the rear of the table. A press-plate can be seen in the background.
The above photo shows a cradle in position ready for use.
The above photo is a close-up of a cradle. Note the small block at the end which raises the end tab. This ensures that the end tab goes on the inside of the box when the press-plate is forced downwards. The raised rail at the rear of the cradle helps to ensure that the pre-formed blank is positioned correctly on the cradle.
The above photo shows a press-plate (flat piece of plywood with a rail on the top).
The above photo shows the end of the press-plate with the section cut out of the corner to enable the end tab to fold up correctly.
The above photo is taken from underneath the table and shows the bearing mounted on the two galvanised pipes with "U" bolts. The carousel can be seen above the pipes without a cradle in place.
