GB2053128A - Improvements in or relating to aerial conveyors - Google Patents

Abstract

In an aerial conveyor of the kind having a carriage 4 mounted on an aerial rope 2 and rope-and-drum winding means extending to the carriage from which rope 25 extends for connection to the load, the range of the conveyor is extended and its operation is made less onerous by providing a rope-and-drum hoist 23 on the carriage and operatively connecting a pair of ropes 19,20 of the rope-and-drum winding means to the hoist drum so that the winding means are actuable to operate the hoist and also haul-back and haul-in the carriage 4. Moreover, the winding means take the form of a plurality of winding devices each comprising rotary drum means 11,12,13 frictionally engaging a coil of the rope to form with the coil a frictional drive capable of feeding the rope, and a winch engaging rope from the frictional drive to tighten the coil on to the drum means and collect and store the detensioned rope fed from the drum means. <IMAGE>

Description

SPECIFICATION Improvements in or relating to aerial conveyors This invention relates to aerial conveyors of the kind comprising an aerial rope, a carriage mounted on the aerial rope for movement along same, and rope-and-drum winding means connected to the carriage and including a rope extending from the carriage for connection to a load so that operation of the winding means effects hoisting and lowering of the load towards and from the carriage and movement of the carriage along the aerial rope between loading and unloading positions.Such a conveyor is hereinafter and in the claims referred to for convenience as "an aerial conveyor of the aforesaid kind." The present invention is particularly but not exclusively concerned with an aerial conveyor of the aforesaid kind for hauling-in ffelled timber(logs)from the forest and comprising a winding machine having a wheeled trailer connectible to a tractor and a mast on the trailer, the aerial rope extending from the head of the mast to an anchorage at the loading position and the winding means including winding devices on the trailer. Usually the haul-in rope connectible to the load is coiled on a winch on the trailer.With the carriage in the loading position the length of unwound haul-in rope is of considerable weight and seriously limits the extent to which a lumberman at the loading position can pull the rope from the winch drum towards the log which is secured to the rope e.g. by a sling or choker attached to the rope. As in typical forest terrain the maximum range achievable with the haul-in rope is only about 300 metres, the scope of operation of aerial conveyors of the aforesaid kind has hitherto been seriously limited.

Therefore, according to the present invention an aerial conveyor of the aforesaid kind is characterised in that the rope-and-drum winding means comprises a rope-and-drum hoist on the carriage and a pair of rope-and-drum haul-in winding devices whereof the ropes are drivingly connected to the hoist drum so that the hoist operates to lift the load on rotation of the devices in opposite directions and the loaded carriage moves to unloading position on rotation of the devices in the same direction.

By virtue of the invention the manual effort required by the lumberman is minimal, as only the relatively short hoist rope (say about 25 metres in length) need be handled, and this short rope need not be pulled from the hoist drum since it is paid out thereby. Consequently, it is now possible to extend the range of the aerial conveyor to about 600 metres.

In existing aerial conveyors of the aforesaid kind, during winding of the loaded haul-in rope on to the winch drum the rope speed increases as layers of rope build up on the drum in haphazard fashion. This increase in speed during haul-in places the lumberman in danger. Moreover, the uncontrolled manner in which the loaded rope coils on to the winch drum during haul-in tends to cause damage to the rope, and damaged rope is expensive to replace.

Therefore, further according to the present invention an aerial conveyor of the aforesaid kind is characterised in that the rope-and-drum winding means include a rope-and-drum winding device comprising a frictional drive whereof rotary drum means frictionally engage a coil of the rope to feed the rope, and a winch engaging rope from the frictional drive and rotatable to wind-in said rope while maintaining the rope coil in frictional engagement with the drum means.

The provision of a winding device which is a combination of frictional drive and storage winch ensures a constant haul-in speed and so improves the safety of the haul-in procedure. Moreover, as the rope leaving the frictional drive is largely detensioned, it is virtually unloaded and forms layers on the winch drum in an orderly fashion, and is therefore less likely to become damaged.

In a preferred construction the drive to the storage winch of the winding device slips to allow slippage of the rope coil in the event of significant overload, so that instantly on overload the winding means are effectively unloaded. Moreover, the drum means of the frictional drive embody shock abs bers which absorb the energy of spasmodic impact loads.

Finally, a pressure relief valve in the hydraulic driving circuit protects the winding means against excess load from any cause.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure lisa side view of the winding machine of an aerial conveyor.

Figure 2 is a front end view of the machine of Figure 1.

Figure 3 is a diagrammatic top perspective view of the aerial conveyor.

Figure 4 is a detail side view of the carriage of the aerial conveyor.

Figure 5 is an enlarged detail view in the direction of the arrow V in Figure 2, showing the winding devices of the winding machine.

Referring to the drawings: An aerial conveyor consists of a winding machine 1, an aerial rope 2 extending from the winding machine to a remote overhead anchorage point 3 (Figure 3), and a carriage 4 wheel-mounted on the rope 2 for movement along the rope between loading and unloading positions. The winding machine 1 consists of a two-wheeled trailer 5, a tow bar 6 on the trailer connectible to a tractor, an hydraulically adjustable telescopic mast 7 on the trailer 5, a protective cabin 8 for the operator, and a housing 9 enclosing a winch 10 and a series of winding devices 11, 12 and 13. Said winch and winding devices are driven by hydrostatic motors in a closed hydraulic circuit whereof a hydrostatic pump is connectible to the P.T.O. of the tractor, suitable controls being provided in the cabin.The hydraulic circuit includes pressure-relief valve means which operate when for any reason overloading occurs in the drives.

The winch 10 engages the aerial rope 2 which passes around a guide pulley 14 on the mast head.

The winding device 11 engages a haul-back rope 15 which passes over a guide pulley 16 on the mast head and thence around an anchored pulley 17 to a coupling 18 connecting the rope to the carriage 4.

The winding devices 12 and 13 engage a pair of haul-in ropes 19 and 20 which pass over guide pulleys 21 and 22 on the mast head and are drivingly connected to a rope-and-drum hoist 23 on the carriage 4. The hoist 23 includes a rotary drum 24 (Figure 4) and a rope 25 wound on the drum 24 and carrying a sling 26 engageable around the log 27 to be conveyed. Fairlead roilers 28 on the carriage guide the hoist rope 25, and a stop plate 29 on the sling is engageable with the carriage to limit the upward lifting movement of the hoist.A driving connection between the pair of haul-in ropes 19 and 20 and the hoist drum is provided on the carriage 4 and includes a pair of winding drums 30 and 31 respectively at opposite sides of the hoist drum 24 and engaged respectively by the ropes 19 and 20, the rope 19 extending from the top ofthe drum 30 and the rope 20 extending from the bottom of the drum 31. The driving connection further includes chainand-sprocket drives 32 and 33 extending between the respective drums 30 and 31 and the hoist drum 24. As shown, the gearing 32 is reduction gearing which enables hauling-in of the log to the carriage with reduced effort, or hauling-in of a heavier load.

The winding device 11 consists of (a) a frictional drive in the form of a driven pair of spaced driving inter-connected pulleys 34 frictionally engaging three complete turns 15A of the rope 15 to feed the rope rearwards and thereby haul the carriage 4 back to the loading position, and (b) a driven winch which winds-in unloaded rope from the frictional drive 34.

The winding devices 12 and 13 which aresimilarto the winding device 11, consist of pairs of drivingly interconnected pulleys 36 and 37 frictionally engaging turns 19A and 20A of the ropes 19 and 20, and driven winches 38 and 39 for maintaining the drives to the ropes 19 and 20 and storing unloaded lengths ofthese ropes.

The winch 10 and the frictional drives 34,36 and 37 are powered by a high-torque dual-speed hydrostatic motor 40 through a common drive shaft 41 and clutches and brakes, the winch having an hydraulic clutch and a hand brake, and each frictional drive having an hydraulically operable clutch/brake combination.

The winches 35, 38 and 39 are powered by, respectively, small, low-torque high-slip hydrostatic motors 42,43 and 44 through shafts 45,46 and 47 (Figure 5) supported at their ends on plummer blocks, the winches being free to move axially on the shafts and thus to synchronise their positions on the shafts with the running ropes while accepting coils and layers of the ropes. Moreover, the motors 42,43 and 44 partially slip to maintain only sufficient tension in the ropes to enable the friction drives to move maximum loads, so that the motors slip to disable the drives on overloading of the conveyor.

However, before maximum loading is reached the winches slow down, thereby providing the operator with a visual warning that the rope systems are approaching maximum tension.

The aerial conveyor is operated as follows: The haul-back winding device 11 is actuated by the machine operator to move the unloaded carriage 4 along the rope 2 from an unloading position adjacent to the machine to a loading position in the forest, light braking being applied to the haul-in devices 12 and 13. The brake of the device 11 is applied.

With the sling 26 gripped by a lumberman, the machine operator actuates the winding device 13 to rotate the drum 31 and thereby rotate the hoist drum 24 in a direction to pay-out the hoist rope 25 and so facilitate dragging of the sling by the lumberman towards the log to be conveyed. During this operation the drum 30 rotates to wind thereon the rope 19.

The winding device 13 is then declutched.

With the log 27 attached to the hoist rope 25, the machine operator actuates the winding device 12 to rotate the drum 30 and thereby rotate the hoist drum 24 in a direction to wind-in the hoist rope and so raise the log until the stop plate 29 strikes the fairlead rollers 28 of the carriage 4. During this operation the drum 31 rotates to wind thereon the rope 20. At this pointthe brake of the haul-back winding device 11 is released sufficiently to allow the carriage 4 to travel forwards with the log suspended thereon. The haul-in winding devices 12 and 13 are then actuated simultaneously to draw the loaded carriage 4 forwards to the unloading position, whereupon the log is lowered to the ground by following the procedure for paying-out the hoist rope 25, the speed of lowering being controlled by the brake of the winding device 13.Once the log has been released, the winding device 12 is actuated to cause raising of the sling 26 to a suspended position, whereupon the carriage 4 is ready for hauling-back to the loading position.

In sum: (a) By providing a rope-actuated hoist on the carriage, the aerial conveyor is given a greatly increased range of operation, and the manual effort required of the lumberman is greatly reduced.

(b) By providing a haul-in winding device in which a pulley-and-coil frictional drive is combined with a storage winch, a constant and therefore safe haul-in speed is ensured, and safety is further enhanced by providing for disabling slippage in the drive to the winch in the event that the haul-in rope is significantly overloaded.

(c) The storage winch co-operating with the pulley-and-coil frictional drive lays detensioned haul-in rope in an orderly fashion on the winch drum, so that the rope life is greatly increased and operating costs are correspondingly reduced.

Claims (14)

1. An aerial conveyor of the aforesaid kind characterised in that the rope-and-drum winding means comprises a rope-and-drum hoist on the carriage and a pair of rope-and-drum haul-in winding devices whereof the ropes are drivingly connected to the hoist drum so that the hoist operates to liftthe load on rotation of the devices in Opposite directions and the loaded carriage moves to unloading position on rotation of the devices in the same direction.

2. A conveyor according to claim 1, wherein the winding means include also a rope-and-drum winding device whereof the rope is connected to the carriage so that the device is operable to haul back the unloaded carriage to loading position.

3. A conveyor according to claim 1 or 2, wherein each rope-and-drum winding device comprises a frictional drive whereof rotary drum means frictionally engage a coil of the rope to feed the rope, and a winch engaging rope from the frictional drive and rotatable to wind-in said rope while maintaining the rope coil in frictional engagement with the drum means.

4. A conveyor according to claim 3, wherein the storage winches of the winding devices have drives which are capable of slipping to allow slippage of the rope coils in-the event of overloading of the ropes.

5. A conveyor according to claim 3 or 4, wherein the storage winches of the winding devices are mounted for axial reciprocation under the action of the ropes being fed thereto, so that the ropes form layers on the drums of the winches.

6. A conveyor according to claim 3 or 4 or 5, wherein the frictional drive of each winding device comprises a pair of spaced drivingly interconnected pulley wheels, and a plurality of elongate rope coils extending around the pulley wheels.

7. A conveyor according to any one of the preceding claims, wherein the driving connection between the haul-in ropes and the hoist drum comprises a pair of winding drums rotatably mounted on the carriage at opposite sides of the hoist drum and engaged by the respective haul-in ropes, and gearing interconnecting the winding and hoist drums.

8. A conveyor according to claim 7, wherein the gearing includes reduction gearing connecting a winding drum to the hoist drum to effect hoisting rotation of the hoist drum.

9. An aerial conveyor of the aforesaid kind, substantially as hereinbefore described with reference to the accompanying drawings.

10. An aerial conveyor of the aforesaid kind, characterised in that the rope-and-drum winding means include a rope-and-drum winding device comprising a frictional drive whereof rotary drum means frictionally engage a coil of the rope to feed the rope, and a winch engaging rope from the frictional drive and rotatable to wind-in said rope while maintaining the rope coil in frictional engagement with the drum means.

11. A winding machine for use in the installation of an aerial conveyor of the aforesaid kind, including a wheeled trailer connectible to a tractive vehicle, a mast on the trailer to carry the aerial rope, and a plurality of rope-and-drum winding devices on the trailer each comprising rotary drum means for frictional engagement with a coil of rope to form a frictional drive for feeding the rope, and a winch engageable with rope from the frictional drive to wind-in said rope while maintaining the rope coil in frictional engagement with the drum means.

12. A winding machine for use in the installation of an aerial conveyor of the aforesaid kind, substantially as herein before described with reference to the accompanying drawings.

13. Carriage means for use in installing an aerial conveyor of the aforesaid kind, comprising a carriage, a hoist drum on the carriage to receive a hoist rope, a pair of winding drums rotatably mounted on the carriage at opposite sides of the hoist drum to receive the ropes of a pair of rope-and-drum winding devices, and gearing interconnecting the winding and hoist drums.

14. Carriage means for use in installing an aerial conveyor of the aforesaid kind, substantially as hereinbefore described with reference to the accompanying drawings.