| 摘要 |
<p>Improved efficiency of a hydraulically actuated crimping tool, providing a reduced period for the crimping operation and/or reduced bulk of the hydraulic crimping tool, would be desirable. It is an object of the invention to at least substantially satisfy at least one of these desires, or at least provide a useful alternative to currently available hydraulically actuated tools. Accordingly, the present disclosure provides a hydraulically actuated tool with first and second pumps. The first pump has first and second piston chambers (123, 124) and a first piston assembly (320) having first and second pistons (321,331) received in the first and second piston chambers (123, 124) respectively. The second pump has a third piston chamber (126) and second piston assembly (340) having a third piston (341) received in the third piston chamber (126). Each of the pistons (321, 331, 341) has an associated valve assembly (200). The first piston chamber (123) has a larger effective cross-sectional area than an effective cross-sectional area of each of the second and third piston chambers, (124,126). A low pressure relief valve (600) communicates the first piston chamber (123) with a hydraulic fluid supply (81) upon pressure within the first valve assembly (200) reaching a predetermined threshold pressure, signifying the end of a high volume, low pressure initial phase of operation.</p> |
