In a mechanical book cradle, the necessary balancing movement takes place via a mechanical lever and spring-based design. Based on the principle of a balance, such book cradles perform the lateral balancing in a self-adjusting manner. Depending on their basic mechanical design, they are usually extremely robust and durable.
Book cradles based on this concept are usually used in scanners up to A2+ format, which are often used as a replacement for copying systems in administration, in the open access area of libraries or in archive digitization.
However, since the compensating movement takes place permanently with this concept, such book cradles in professional systems also have a so-called book cradle lock. This works like a brake that prevents the book cradle from moving during the scan and thus prevents blurring. In addition, there is often also the option of locking the book cradle as a whole by hand or foot switch and using it only as a flat support table.
Such a book cradle also offers the possibility of so-called book spine exemption. This is a mechanism that opens a gap several centimeters wide between the book plates, into which the spine can be gently inserted.
Another option that such book cradles very often have are scan triggers on the document table. These offer an enormous advantage, especially when digitizing without a pressure plate. The user is thus able to trigger the scan comfortably by hand, even if he needs one hand to hold or press down the template. In professional systems, the scan triggers are integrated into the support plates of the book cradle in such a way that they are easy to operate regardless of the size, thickness or position of the originals and without damaging them.
Glass plates or Makrolon pressure plates are further optional features of such book cradles that can be used if the pages of the template are to be pressed down gently and carefully.
Advantages:
- Robust and durable
- Easy to handle
- A wide range of features for professional systems, such as automatic locking during scanning
- Locking of the book cradle by switch to the fixed support table
- Optional book spine release
- Scan trigger on the support plates of the book cradle
- Pressure aid made of glass or Makrolon©
Disadvantages:
- With most suppliers, the book thicknesses which can be processed are designed for height adjustment up to a maximum of 10 cm.
- The maximum permissible weight of books for which the compensating movement still functions according to the principle of a scale is limited to a few kilograms