Working comparisons show the T590’s overall design efficiency
By WALT MOORE, Editor W 14
hen designing its new M-Series models, Bobcat convened a number of focus groups and encouraged members of the groups—equipment
owners
and operators—to speak their minds about machine features and performance. Practical insights gained from these sessions gave the company’s engineering staff an added resource when developing M-Series models, which, says Bobcat, combine the best of the preceding K-Series with new features that add overall efficiency to the machine—even in the details. “A surprising amount of design work went into
small items,” says Jeret Hoesel, Bobcat’s training strategy manager, but previously a lead engineer on the M-Series project. “For instance, you’ll find very few 90-degree fittings in the hydraulic plumbing of an M-Series machine, because when you force oil to make right-angle bends, you waste horsepower and generate heat.” Further gains in overall hydraulic efficiency,
says Hoesel, result from such changes as elevating the M-Series reservoir above the pumps, compared with its position below the pumps in K-Series machines. Gravity provides a positive pressure at the M-Series pumps, he says, which minimizes power requirements to overcome negative pressure.
Bobcat also redesigned the main hydraulic control
valve, which gives priority to the tilt circuit if an attachment stalls and goes over relief. Before, lift and tilt functions were disabled in a stall, necessitating stopping the attachment and repositioning the machine. Now, a simple adjustment of the attachment with the tilt cylinders solves the problem. The new valve also helps keep attachments properly positioned by eliminating any tendency for lift- and tilt-circuit creep during high-pressure operation.
January 2013 | Construction Equipment Reprinted from Construction Equipment, January 2013