Swing mechanism for an earth-moving apparatus

A swing mechanism for an earth moving apparatus having a main frame, a swing frame for movement about a vertical axis and a boom which is mounted on said swing frame for movement about a horizontal axis, said swing mechanism comprising:

• (a) a first guide which is fixed to the main frame and which extends horizontally and laterally of said vertical axis toward one side of said main frame, said first guide having a first elongated vertical guide surface which faces said main frame,
• (b) a second guide which is fixed to the main frame and which extends horizontally and laterally of said vertical axis toward the opposite side of said main frame, said second guide having a second elongated vertical guide surface which faces said main frame,
• (c) a first slide member which is in sliding engagement with said first guide surface,
• (d) a second slide member which is in sliding engagement with said second guide surface,
• (e) a first elongated flexible drive connector, one end of which is fixed to said first slide member, and the other end of which is operatively connected to said swing frame at a first location so that movement of said first slide member away from said vertical axis toward said one side of said main frame causes said swing frame to swing toward said opposite side of said main frame,
• (f) a second elongated flexible drive connector, one end of which is fixed to said second slide member and the other end of which is operatively connected to said swing frame at a second location which is vertically spaced from said first location so that movement of said second slide member away from said vertical axis toward said opposite side of said main frame causes said swing frame to swing toward said one side of said main frame,
• (g) a first single acting fluid actuator for positively moving said first slide member along said first guide surface away from said vertical axis toward said one side of said main frame, one end of said first fluid actuator being pivotally connected to said main frame for swinging about a vertical axis, the opposite end of said first fluid actuator being pivotally connected to said first slide member, said first fluid actuator having a first axis of actuation which is at a convergent angle to said first guide surface from said one end of said first fluid actuator,
• (h) a second single acting fluid actuator for positively moving said second slide member along said second guide surface away from said vertical axis toward said opposite side of said main frame, one end of said second fluid actuator being pivotally connected to said main frame for swinging about a vertical axis, the opposite end of said second fluid actuator being pivotally connected to said second slide member, said second fluid actuator having a second axis of actuation which is at a convergent angle to said second guide surface from said one end of said second fluid, and
• (i) control means for selectively actuating said first and second fluid actuators.