Leather hides undergo wet dying followed by a natural air-drying process. During this process of dying and natural air-drying, leather hides tend to shrink. This shrinking needs to be corrected so as to achieve a uniform fiber structure. Toggling is an essential procedure of stretching the leather hides to achieve uniform fiber structure
The Toggling process consists of the following steps:
- The leather hide is spread over a metal perforated mesh frame (10 x 10 Sq. ft.). The metal frame consists of two separate sections that can be moved sideways (refer Fig. 1). The vertebral portion of the hide is placed along the centre of the metal frame, the split section.
- The periphery of the hide is firmly fixed by clipping the leather hide at multiple places to the metal frame (approximately 75 clips per hide) . This will ensure that the hide is firmly attached to the mesh (refer Fig. 2). The frame is turned around and another hide is clipped on the backside of the frame in a similar fashion. Two hides can be accommodated on each metal frame – one on each side.
- The frame along with the leather hide is taken into a heating chamber which heats the leather hides evenly. During this heating process, the two sections of the frame are moved sideways (refer Fig 1), by a pneumatic pusher. This helps the hide to stretch uniformly.
- Once the hides come out of the heating chamber, the leather hides are unclipped and removed.
The process of toggling (clipping and unclipping) is manual, requires several skilled people to complete this task. The process is also repeated for all the leather hides that are to be processed.
We are looking for either of the following two options:
- A system that will clip the hide after it is placed on the metal mesh frame and then unclip after the hide comes out of the heating chamber
- An alternate automatic system to achieve the uniform fiber structure in the hide
If the solution is for automating the clipping and unclipping:
- The proposed system should automatically hold the leather in place and clip all around its periphery as in Figure 3.
- The time taken for clipping should be less than 3 minutes.
- The system should be able to handle hides of various shapes and sizes.