Title: Double cylinder over-center aerial device

Abstract: An aerial device includes a boom support structure, a boom pivotally secured to the support structure, and first and second boom lift hydraulic actuators. The first and second boom lift hydraulic actuators are operated in tandem to raise, lower, and hold the boom in position. The first and second boom lift hydraulic actuators are pivotally connected between the boom support structure and the boom and are disposed with respect to the boom pivot axis so that regardless of boom position, one of the first and second actuators is under tension and the other is under compression. This eliminates the danger of loss of lift of the boom caused by end gland failure of a lift actuator.

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Inventors: Raymond, James W. (Duluth, MN, US)

Application Number: 911340
Filing Date: 1978-06-01
Publication_date: 1980-01-29
Assignee: Reach-All Manufacturing & Engineering Co. (Duluth, MN)
Primary Class(es): 52/115 52/117
Other Classes:
US Patent Ref:

3467217	Sep, 1969	Zwight	182/46.
3809180	May, 1974	Grove	182/2.
3834488	Sep, 1974	Grove	182/2.
3841436	Oct, 1974	Grove	182/2.
3888317	Jun, 1975	Walters	52/115.
3937340	Feb, 1976	Grove	182/2.
4074821	Feb, 1978	Long	214/138.

Other Refs:
Primary Examiner: Friedman, Carl D.
Assistant Examiner:
Attorney: Kinney, Lange, Westman & Fairbairn