公开(公告)号：US3877544A

公开(公告)日：1975-04-15

申请号：US37909773

申请日：1973-07-13

Applicant: DEL MAR ENG LAB

Inventor： MCCOLLUM FENWICK HARRIS

IPC: B66F11/04

CPC classification number: B66F11/044

Abstract: A lazy tong or scissor-type of extendible boom structure having one end mounted on a platform. The boom structure can be extended, elevated, and/or rotated independently by drive structure mounted on the platform and a load-carrying basket is mounted on the opposite end of the boom. The boom comprises a pair of parallel lazy tongs, each comprising pairs of beams which are pivoted to one another in scissorlike fashion, the pivoted beams opposite each other on the two lazy tongs forming one ''''bay.'''' Stress transmitting rigid structural cross members are fixed between the inner beams of each bay and similar cross members are nested at interference-free positions and between the outer beams of each bay to balance the torque within the pair of lazy tongs and prevent rotation of the beams and consequent twisting of the extended boom when an asymmetrical load is applied thereto, such as by an off-center load in the platform or basket or by the locating of the platform base in a nonhorizontal plane.

Abstract translation: 一种具有安装在平台上的一端的延伸钳或剪刀型可伸缩臂结构。 悬臂结构可以通过安装在平台上的驱动结构独立地延伸，升高和/或旋转，并且载重篮安装在起重臂的相对端上。 起重臂包括一对平行的懒惰钳，每个钳子包括成对的梁，它们以剪叉状的方式彼此枢转，在两个懒惰的钳子上相对地枢转的梁形成一个“托架”。 应力传递刚性结构横向构件固定在每个隔间的内梁之间，类似的横向构件嵌套在无干扰位置和每个隔间的外梁之间，以平衡一对懒惰钳内的扭矩，并防止梁的旋转 并且当对其施加非对称负载时，例如通过平台或筐中的偏心负载或者通过将平台基座定位在非水平面中，扩展起重臂的扭转。