The overall project you are looking for will probably be found here:
vi. Pitting: The traditional, and by no means abandoned, method of removing the pit from the date is by hand, mostly with the use of a knife cutting open one side of the fruit, removing the pit and folding the two sides of the date together to make the cut almost invisible (Iraq). If done properly this method also provides an opportunity to check on insect infestation. In Iran field pitting is done in certain areas with a blunt needle piercing the pit out end-wise. This method can be considered the manual forerunner of the mechanical date pitters that have been devised. As can be expected hand pitting is rather slow and yield per hour does not normally exceed 5 kg (139, 363). Pitted dates pressed into blocks and sliced create an attractive marbled product (Fig. 50).
Figure 50: Slice of Pitted, Pressed Dates
Figure 50: Slice of Pitted, Pressed Dates
For soft dates the pit can be squeezed out between the fingers at the same time removing the skin. This is done for the preparation of agwa, a soft date paste preserved in jars (a.o. in Egypt) (139). This principle of removing the pit could be compared to mechanical date maceration, by which the pits are removed but the date loses its identity and is produced as a coarse date pulp.
The working principles of both mechanical date pitters are as follows: in the whole date pitter incoming dates are lined up vertically in cups, by a special feeder. The cups are tightened around the date to hold them in position and move them intermittently along an endless belt (90-130 strokes per minute) up to the pitting head. Here pins will descend and pierce out the pits end-wise. The pits drop underneath the belt and are collected whilst the cups with pitted dates move on. The grip on the date is released and the conveyor turns down at which point the pitted fruit drops out of the cups and is collected. Because most dates and their pits are longitudinal in shape, the vertical alignment in the cups is of utmost importance. Preferably dates should be graded for size and correlated to the cup size. Output of these machines is in the order of 250-400 kgs/hr. (38, 160, 580).
The date macerator works on the principle of feeding dates between two almost touching rollers turning in opposite directions. One roller is covered with a thick layer of rubber of a determined density, the other consists of notched steel disks separated by washers about 2 cm smaller in diameter and 0.5 cm wide. When dates are fed between the rollers they are squashed, where the two rollers touch and the flesh penetrates in the slits between the notched disks but the pits, being too big for these, are momentarily pushed in the rubber. Whilst the pit will almost immediately again be pushed out of the rubber the date flesh will rotate along the toothed roller until being removed by scrapers positioned after about half a turn of the roller. Both flesh and pits are collected in separate chutes.
The operation will now be repeated with two rollers with all dimensions reduced with the aim of removing the calyces. The machine can give good results, up to 1,000 kg/hr, provided dates are used of the right moisture content, which if necessary should be obtained by artificial means prior to maceration. The resulting macerated dates are a starting point for the manufacture of date products (see Chapter 2).
e. Packing whole dates: Loose tamr is frequently sold in the markets, not only in date producing countries, but they are also still commonly found on the stalls of the weekly open- air markets around the Mediterranean and Northern Europe (Fig. 51). Here they are part of the dried fruits and nuts assortment such as apricots, prunes, carob, peanuts, almonds etc. The type of container and packaging material used for tamr in the national and international date trade is varied and can be subdivided in:
Information from http://www.fao.org/docrep/t0681E/t0681e05.htm
Ferrum company used to make date de-pitting machines. They probably worked like this::http://www.ferrum.ch/html/es/conserventechnik/15_787.asp
I hope this helps.