Claims
- 1. In a walking dragline excavator having a roller circle, a main frame mounted on said roller circle for swing movement about the central vertical swing axis of said roller circle, a boom provided with a pair of boom feet connected to a front end of said main frame forwardly of said central vertical swing axis and proximate to a segment of said roller circle, a hoist line operatively connected to hoist machinery mounted on said main frame and passing over and suspending from a point on said boom, a bucket operatively connected to a suspended portion of said hoist line, a drag line operatively interconnecting said bucket and drag machinery mounted on said main frame, the front end of said main frame having insufficient stiffness for adequately resisting deflection and substantially uniformly distributing the boom weight and hoist load imposed thereon over a segment of said roller circle disposed beneath the front end of said main frame, an improved means for supporting said boom by means of pendants and substantially uniformly distributing the boom weight and hoist load on said roller circle comprising an upright structure having an upper end and a pair of lower legs connected to said main frame, the upper end of said upright structure being operatively connected to said pendants and also being operatively connected to said main frame rearwardly of said lower leg connections, said lower leg connections of said upright structure being disposed intermediate said boom feet connections, proximate to a segment of said roller circle, and spaced arcuately from said boom feet connections, said lower leg connections of said upright structure being separate from and independent of said boom feet connections, whereby loads transmitted through said boom feet connections and the lower leg connections of said upright structure, and through the front end of said main frame to said roller circle, will be substantially uniformly distributed over a segment of said roller circle disposed beneath the front of said main frame.
- 2. An improved support means according to claim 1, wherein the arcuate spacing between said lower leg connections of said upright structure is no greater than one-half the arcuate spacing between said boom feet connections.
- 3. In a walking dragline excavator having a roller circle, a main frame mounted on said roller circle for swing movement about the central vertical swing axis of said roller circle, a boom provided with a pair of boom feet connected to a front end of said main frame, forwardly of said central vertical swing axis and proximate to a segment of said roller circle, a hoist line operatively connected to hoist machinery mounted on said main frame and passing over and extending from a point on said boom, a bucket operatively connected to a suspended portion of said hoist line, a dragline operatively interconnecting said bucket and drag machinery mounted on said main frame, the front end of said main frame having insufficient stiffness for adequately resisting deflection and substantially uniformly distributing the boom weight and hoist load imposed thereon over a segment of said roller circle disposed beneath the front end of said main frame, an improved gantry for supporting said boom by means of pendants and for transmitting the boom weight and hoist loads to said roller circle comprising a pair of front legs and at least one rear leg, said legs having lower ends connected to said main frame and upper ends operatively connected to form an upright structure, the connections of the lower ends of said gantry front legs to said main frame being disposed intermediate said boom feet connections, proximate to a segment of said roller circle, and spaced arcuately from said boom feet connections, and the connections of the lower end of the rear leg is spaced rearwardly of the front gantry leg connections, said gantry front leg connections being separate from and independent of said boom feet connections, whereby loads transmitted through said boom feet and gantry front leg connections and the front end of said main frame to said roller circle will be substantially uniformly distributed over a segment of said roller circle disposed beneath the front end of said main frame.
- 4. An improved gantry according to claim 3 wherein the spacing between the connections of the lower ends of said gantry front legs to said main frame is no greater than one-half the spacing between said boom feet connections.
- 5. An improved gantry according to claim 4 wherein the connections of the lower ends of said front gantry legs to the main frame are disposed on a transverse line disposed forwardly of said vertical swing axis, and the connection of the lower end of said rear gantry leg to the main frame is spaced rearwardly of said transverse line.
- 6. An improved gantry according to claim 4 wherein the connection of the upper ends of said front and rear gantry legs is at a point within 15 feet forwardly or rearwardly of said vertical swing axis.
- 7. An improved gantry according to claim 4 including a lower drag line fairlead sheave mounted on said front gantry legs, and an upper drag line fairlead sheave mounted on said gantry front legs above said lower fairlead sheave, and wherein said drag line passes under said lower fairlead sheave and over said upper fairlead sheave in passage to said drag machinery.
- 8. An improved gantry according to claim 7 wherein said lower fairlead sheave is mounted for swivel movement about a vertical axis.
- 9. An improved gantry according to claim 8 wherein the connections of the lower ends of said front gantry legs to the main frame lie on a transverse line disposed forwardly of said vertical swing axis, and the connection of the lower end of said rear gantry leg is spaced rearwardly of said transverse line.
- 10. A gantry according to claim 9 wherein the connection of the upper ends of said front and rear gantry legs is at a point within 15 feet forwardly or rearwardly of said vertical swing axis.
- 11. An improved gantry according to claim 3 including a lower drag line fairlead sheave mounted on said front gantry legs and an upper drag line fairlead sheave mounted on said front gantry legs above said lower fairlead sheave, and wherein said drag line passes under said lower fairlead sheave and over said upper fairlead sheave in passage to said drag machinery.
- 12. An improved gantry according to claim 11 wherein said lower fairlead sheave is mounted for swivel movement about a vertical axis.
- 13. An improved gantry according to claim 12 including means mounted on said front gantry legs intermediate said lower and upper fairlead sheaves for guiding a segment of said drag line between said lower and upper fairlead sheaves.
- 14. An improved gantry according to claim 11 wherein each of said front gantry legs comprises a truss, said trusses are interconnected by bridging members and said upper and lower fairlead sheaves are mounted on said bridging members.
- 15. An improved gantry according to claim 14 wherein the connection of the lower end of said rear gantry leg to said main frame is disposed rearwardly of said vertical swing axis.
- 16. An improved gantry according to claim 15 wherein the spacing between the connections of the lower ends of said gantry front legs to the main frame is no greater than one-half the spacing between said boom feet connections.
- 17. An improved gantry according to claim 16 wherein the connections of the lower ends of said front gantry legs lie on a transverse line disposed forwardly of said vertical swing axis, and the connection of the lower end of said rear gantry leg is disposed rearwardly of said transverse line.
- 18. An improved gantry according to claim 16 wherein the connection of the upper ends of said front and rear gantry legs is disposed at a point within 15 feet forwardly or rearwardly of said vertical swing axis.
Parent Case Info
This is a continuation of application Ser. No. 427,428, filed Dec. 21, 1973 now abandoned, which was a continuation of Ser. No. 120,167 filed Mar. 2, 1971 now abandoned.
US Referenced Citations (14)
Foreign Referenced Citations (1)
Number |
Date |
Country |
1,241,074 |
May 1967 |
DT |
Non-Patent Literature Citations (2)
Entry |
Schield Bantom Co., Waverly Iowa, Catalog No. 350, July 18,1959. |
American Revolver Cranes, Form No. 400-RS-15-62 American Hoist & Derrick Company. |
Continuations (2)
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Number |
Date |
Country |
Parent |
427428 |
Dec 1973 |
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Parent |
120167 |
Mar 1971 |
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