A SIMPLIFIED METHOD TO DESIGN SUSPENDED CABS FOR COUNTERBALANCE TRUCKS
✍ Scribed by P. LEMERLE; P. BOULANGER; R. POIROT
- Publisher
- Elsevier Science
- Year
- 2002
- Tongue
- English
- Weight
- 473 KB
- Volume
- 253
- Category
- Article
- ISSN
- 0022-460X
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✦ Synopsis
A &&low-frequency'' suspension system, placed between the driving cab and chassis of an existing fork lift truck was designed. The aim of this project was to develop a design procedure which is easy to implement and suitable for all types of fork lift trucks. It was also to show how the use of numerical simulation could be helpful to optimize the e$ciency of such suspension systems. The cab speci"cations were: (1) to achieve a vertical vibration attenuation of at least 50% when this truck is tested under severe but realistic conditions, (2) to operate with no speci"c adjustment for drivers weighing between 60 and 100 kg, (3) to be e$cient with a reasonable dynamic stroke (about 3 cm maximum). The suspended cab was modelled using ADAMS software. In the simpli"ed method, the input acceleration signals (at the four "xing points of the cab) were not computed from a vehicle model (chassis and wheels) but directly measured under various driving conditions (passage of two or four wheels over an obstacle with a loaded or unloaded fork lift truck). This model allowed evaluation of the theoretical attenuation, obtained below the driver's seat along the three axes, in comparison with an in"nitely rigid suspension. The attenuation ratio was calculated for several values of the characteristics of the suspension components (sti!ness and damping). Similarly, for every design value tested, the design constraints were evaluated and at the end of this parametrical study, optimal suspension components were found. Finally, the suspended cab was built according to the results of the parametrical study and measurements subsequently con"rmed that the attenuation of vertical accelerations was more than 50%.