Drive system for a telescopic boom

Claim 2

In an extensible boom having a plurality of boom sections including a base boom section which is rotatably connected to a turret for pivotal motion in a vertical plane about a pivot axis, and an elevation cylinder connected to said turret and said base boom section to control the elevation of said boom, the improvement comprising: an extension cylinder having one end connected to said turret at a point which is laterally spaced a substantial ditance from said pivot axis; a trolley slidably connected to said base boom section for motion along the lengthwise dimension thereof and connected to the other end of said extension cylinder; a second boom section slidably mounted to the base boom section for telescopic motion between a retracted position in which the boom reach is minimal and an extended position in which the boom reach is at a maximum; and extension drive means connecting said trolley with said second boom section to alter the reach of said boom by sliding said second boom section with respect to said base boom section in response to the sliding motion of said trolley.

Claim 3

The extensible boom as recited in claim 1 in which said extension drive means includes a rope and pulleys which form a loop that contains the trolley and said second boom section, and wherein said second boom section slides outward away from said pivot axis to increase boom reach when said trolley slides inward toward said pivot axis and said second boom section slides inward toward said pivot axis to reduce boom reach when said trolley slides outward away from said pivot axis.

Claim 4

The extensible boom as recited in claim 2 in which said trolley is slidably retained to said base boom section by a track which is fastened to the underside of said base boom section.

Claim 5

In an extensible boom having a plurality of boom sections including a base boom section which is rotatably connected to a turret for pivotal motion in a vertical plane about a pivot axis, and an elevation cylinder connected to said turret and said base boom section to control the elevation of said boom, the improvement comprising: an extension cylinder having one end connected to said turret at a point which is laterally spaced a substantial distance from said pivot axis; a trolley slidably connected to said base boom section and rotatably connected to the other end of said extension cylinder; and extension drive means connecting said trolley with a second boom section to alter the reach of said boom in response to the sliding motion of said trolley, said extension drive means including: a boom point pulley rotatably connected to said base boom section near its outer end; a boom foot pulley rotatably connected to said base boom section near iTs other end; an extension rope having one end connected to said base boom section and its other end connected to said second boom section, said extension rope extending around one of said trolley pulleys and around said boom point pulley; and a retraction rope having one end connected to said base boom section and its other end connected to said second boom section, said retraction rope passing around the other of said trolley pulleys and around said boom foot pulley.

Claim 6

In an extensible boom having a plurality of boom sections including a base boom section which is rotatably connected to a turret for pivotal motion in a vertical plane about a pivot axis, and an elevation cylinder connected to said turret and said base boom section to control the elevation of said boom, the improvement comprising: an extension cylinder having one end connected to said turret at a point which is laterally spaced a substantial distance from said pivot axis; a trolley slidably connected to said base boom section and rotatably connected to the other end of said extension cylinder; and extension drive means connecting said trolley with a second boom section to alter the reach of said boom in response to the sliding motion of said trolley, said extension drive means including: a boom point pulley rotatably connected to said base boom section near its outer end; a boom foot pulley rotatably connected to said base boom section near iTs other end; an extension rope having one end connected to said base boom section and its other end connected to said second boom section, said extension rope extending around one of said trolley pulleys and around said boom point pulley; and a retraction rope having one end connected to said base boom section and its other end connected to said second boom section, said retraction rope passing around the other of said trolley pulleys and around said boom foot pulley.

Claim 7

The extensible boom as recited in claim 4 in which said boom includes a third boom section slidably connected to said second boom section for telescopic motion and said extension drive means includes a second rope and pulley drive which connects to each of said three boom sections and which is responsive to the position of said second boom section with respect to said base boom section to position said third boom section with respect to said second boom section, such that when the second boom section is extended from said base boom section, said third boom section is extended a corresponding amount from said second boom section.

Claim 8

In an extensible boom mounted at one end to a turret for pivotal motion in a vertical plane, said boom having a plurality of boom sections which are slidably mounted to one another for telescopic motion between a retracted position and an extended position, and having means for elevating and lowering said boom in said vertical plane, the improvement therein comprising extension means for automatically altering boom reach in response to changes in elevation, said extension means including: an extension cylinder having one end connected to said turret at a point which is laterally spaced a substantial distance from the point at which said boom pivotally connects to said turret; a trolley slidably mounted to the innermost boom section for motion along the lengthwise dimension of said boom, said trolley being coupled to the other end of said extension cylinder for operation thereby; and rope and pulley drive means which couple the trolley with an outer boom section to impart a sliding motion thereto with respect to said inner boom section when said trolley slides with respect to said inner boom section, and wherein the trolley slides with respect to the inner boom section when said elevating means is operated to retract said outer boom section when said boom is lowered and to extend said outer boom section when said boom is elevated.

Claim 9

In an extensible boom mounted at one end to a turret for pivotal motion in a vertical plane, said boom having a plurality of boom sections which are slidably mounted to one another for telescopic motion between a retracted position and an extended position, and having means for elevating and lowering said boom in said vertical plane, the improvement therein comprising extension means for automatically altering boom reach in response to changes in elevation, said extension means including: an extension cylinder having one end connected to said turret at a point which is laterally spaced a substantial distance from the point at which said boom pivotally connects to said turret; a trolley slidably mounted to the innermost boom section for motion along the lengthwise dimension of said boom, said trolley being coupled to the other end of said extension cylinder for operation thereby; and rope and pulley drive means which couple the trolley with an outer boom section to impart a sliding motion thereto with respect to said inner boom section when said trolley slides with respect to said inner boom section, and wherein the trolley slides with respect to the inner boom section when said elevating means is operated to retract said outer boom section when said boom is lowered and to extend said outer boom section when said boom is elevated.

Claim 10

The improvement as recited in claim 6 in which said rope and pulley drive means provides a displacement gain of more than one to slide said outer boom section a proportionately greater distance than the trolley slides.