The operation and application of medium and big square balers - Part 3: The knotter, wire twister and bale preparation

Categories: ZambiaPublished On: 12th December 2019

The operation and application of medium and big square balers – Part 3: The knotter, wire twister and bale preparation

1007 words

balers 1

Photo: thefarmingforum.co.uk

by GJ Stoltz (Reg Eng Tech)

When tying a knot in twine, the one end of the twine is held firmly in the twine disk by the twine holder. While the bale is formed, with every compression stroke of the plunger, twine is pulled from the twine box and passed around three sides of the bale (see Figures 1 and 2).

Figure 1: The twine disk holds one end of the twine.

We thank the ARC Agricultural Engineering in South Africa who made the information on square balers available to the readers of ProAgri Zambia.

Figure 2: The twine disk holds the one end of the twine while the twine is wrapped around three sides of the bale when the hay is compressed in the bale chamber. Twine is fed from the twine box through the eye of the needle.

When the bale measuring wheel starts the tying mechanism, the needles bring the twine across the end of the bale, through the slots in the plunger. A needle will then move through the guide in the twine knife arm and take the twine across the billhook and into the twine disk. The same happens to the other needle. The twine disk then turns to secure both ends of the twine against the twine holder (see Figure 3).

Figure 3: The needle moves through the guide, takes the twine across the bill hook and into the twine disk which secures both ends of the twine.

The bill hook then rotates and as it turns, loops the twine around the hook and the jaw opens to receive both strings of twine (see Figures 4 and 5).

Figure 4: The bill hook rotates and loops both strings of twine around the hook.

The knife then cuts both strings of twine between the bill hook and the disk and the bill hook closes while holding both strings of twine. The wiper then wipes the looped twine from the bill hook while the bill hook jaws are still holding the two strings of twine (see Figure 6). As the twine is wiped off the bill hook by the wiper, the knot is completed and pulled tight (see Figure 7). The knot must be tight enough to bind the bale properly, and as the bale moves on, the knot leaves the knotter area and moves with the bale.

Figure 5: While rotating the bill hook jaws open to receive both strings of twine.

In the meantime, the needle has started its downward stroke, leaving twine in the disk to be wrapped around the next bale (see Figures 6 and 7). Both needles have the same operations completed at the same time and after the knotting process, the needles return to their “home” position at the bottom of the bale chamber.

Figure 6: The wiper starts wiping the looped twine from the bill hook while the jaws are still holding the twine.

Figure 7: As the twine is wiped off the bill hook by the wiper, the knot is completed and pulled tight.

Wire twister:

The wire twisting operation is triggered by the bale measuring wheel and accessories and proceeds as follows: When the needle retracted after its previous cycle, the end of the wire was anchored by the wire gripper, and the wire was pulled around three sides of the bale (see Figure 8).

Figure 8: The wire is anchored by the wire gripper.

When the new bale reaches its proper length, the measuring wheel trips the twister drive mechanism. As the needle goes upwards, it takes the wire that was wrapped around three sides of the bale already, and carries it up the front of the bale, through the plunger slots.

The needle continues to rise and positions the wire in the notch, in the shear plate, on the opposite side of the anchored wire. The twister hook on the twister shaft starts rotating and twisting the two strands of wire. (The previously anchored, and the needle wire) (see Figure 9).

Figure 9: The twister hook starts to rotate, twisting the previously
anchored wire and the needle wire together.

At this stage, the wire gripper releases the previously anchored wire. The needle wire is sheared and the other end is now anchored, for the next bale, as the wire gripper moves to the other side. The needle returns “home” and the twister hook makes five or six rotations, twisting the wire ends together (see Figure 10).

Figure 10: The needle returns “home” and the twister hook makes
five or six rotations, twisting the wire ends together.

As the completed bale is pushed from the baler, it pulls the twisted knot off the twister hook. Hay for the next bale pulls the anchored wire into position for the next twisting cycle and this entire process is duplicated simultaneously for each wire on the bale (see Figure 11).

Figure 11: The twisted knot is pulled
off the twister hook.

Baler preparation:

Experienced operators can run a square baler efficiently for high productivity. With the baler attached to the tractor, make a final inspection and prepare the baler. The baler must run level (see Figure 12).