Concrete finishing trowel with improved rotor assembly drive system
US6250844A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 13, 1999 |
| Grant date | Jun 26, 2001 |
| Priority date | — |
| Expiry date | Jul 13, 2019 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE04F21/247
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A concrete finishing trowel has one or more driven rotor assemblies coupled to an engine or other power source of the machine by a novel torque transfer system including at least one flexible shaft and possibly including a variable speed ratio torque converter assembly. The flexible shaft, preferably comprising a flexible wound wire shaft, bends to accommodate tilting movement of the associated rotor assembly that occurs upon a steering operation, thereby eliminating the need for high-maintenance universal joints or other, less durable equipment. The torque converter assembly, preferably taking the form of a pair of variable speed clutches each having variable diameter sheaves, permits the speed and torque ratios of the drive system to change with increases in engine speed so that the same machine can be effectively used for both low speed/high torque floating operations and for high speed burning operations. Multi-application use is further facilitated by moving the blades axially along their support arms to permit the blades to operate in either an overlapping mode or a non-overlapping mode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.