Patent Application
20160297651
The present invention relates to a winch for moving along a lifting strand such as a rope or cable, and in particular a winch to which a user may attach him/herself to move up and down along a rope.
The invention relates to the field of winches and in particular grip pulley winches. Grip pulley winches should not be confused with drum winches or the like. This is because winches with a grip pulley have the characteristic of being usable with cables of unlimited length due to the selected principle of gripping the cable within a single groove of the grip pulley in which the cable is wrapped around at least one turn.
Such winches have been developed for professional, safety and sporting purposes: access to building facades, masts for wind turbines or ships, working areas in lift shafts or silos, mountain rescue and climbing, etc. They have the following advantages over other winches:
EP 1 030 726 for example describes a grip winch comprising a motor, the drive shaft of which is coupled to a pulley with a single V groove, mounted on a frame. The winch comprises a locking member attached to the frame which allows the winch to climb the rope and locks as soon as the climbing force ceases. A guide ring is positioned above and close to the pulley. The rope is placed by the user in such a way as to pass through the guide ring, wrap around the pulley and pass once more through the same guide ring, the rope therefore being engaged around 180° in the pulley groove. The design of the pulley part of this winch, with a contact angle of 180°, entails the need for a locking member. Another disadvantage is associated with the taut strand and the slack strand necessarily passing through the guide ring, which involves the rope entering and exiting via the top of the winch. In the case of a rope, which does not have the longitudinal stiffness of a cable, upwards extraction may prove problematic and cause jamming.
Other devices using grooved pulleys for hauling may be cited. Le GB 2057871 describes, for example, a life-saving device for lowering people by abseiling comprising a frame, to be attached to the person to be lowered, and a grooved pulley for the cable, the latter being guided around the pulley over an angle of greater than 180 degrees. The pulley is braked by a mechanism which takes account of the person's weight.
GB 2057871 describes a winch of the boat winch type, for hauling sails. EP0876987 describes an emergency lift system intended to be installed on the outside of a building. WO2010049597 describes a self-blocking, anti-panic and position-locking belaying/descending device.
The object of the present invention is that of proposing an improved winch which does not have the above-stated disadvantages.
According to the invention, said object is achieved by a winch with a grip pulley for a lifting strand comprising:
The winch according to the invention enables ascent and descent along a lifting strand of unlimited length (the term lifting strand is here used to denote a rope, in particular a synthetic rope, a cable, etc.). It will be appreciated that the design of the winch has been particularly intended for ropes, which results in the slack strand exiting downwards, and overcomes the tendency towards jamming, at variance with winches in which the slack strand exits via the top.
Furthermore, the design of the winch according to the invention, which uses a grip pulley in combination with a clamping pulley, permits forces to be controlled in such a manner as to ensure locking of the rope in the grip pulley in the absence of drive, so removing the need for a specific locking member. The proximity of the guide and clamping pulleys furthermore permits a large wrap angle of the lifting strand on the pulley, so increasing the lifting force.
The guide pulley and the clamping pulley are preferably positioned in such a manner that the lifting strand is engaged in the groove of the grip pulley over an angle of at least 200°, preferably at least 280° and more preferably between 300 and 340°.
In order to be driven, the grip pulley is preferably mounted on a shaft coupled to a manual or motor-powered drive mechanism, generally via a reducing gearbox. The motor may be an electric motor or heat engine.
The motor control makes it possible to cause the grip pulley to rotate in both directions of rotation, so enabling the user to control the ascent and descent of the winch on the lifting strand.
The design of the winch furthermore permits great compactness which therefore suits it for use as an autonomous portable unit, the bulk of which will still be dependent on the drive mechanism.
The winch advantageously comprises an anchoring point which, depending on the application, will serve to attach a flexible link or a rigid structure capable of supporting a user or a filler.
The clamping pulley is preferably forced towards the grip pulley by a resilient means, in particular a compression spring.
The guide and clamping pulleys are preferably retractable, which makes it possible to wrap the rope around the grip pulley on a continuous portion of the rope (and not just at the end of the rope).
According to one variant, the clamping pulley is carried by an arm mounted pivotably on the frame about a pin and cooperates with a toggle lever type mechanism for locking the clamping pulley into a working position against the lifting strand.
The drive pulley is preferably of the type having a V groove. Grip may be improved by a relief pattern on the sidewalls of the groove.
In practice, the rope and the grip pulley are selected to suit one another. In order to limit wear, a pulley with a wrap diameter of at least 150 mm will be selected with a wrap coefficient of the order of 14 to 18 being desirable.
Other details and features of the invention will emerge from the following detailed description of at least one embodiment, provided by way of illustration with reference to the appended drawings, in which:
In the figures, the same reference signs denote identical or similar elements.
A guide means is provided to guide the rope 20 under tension from the upper region of the frame towards the lower region thereof and comprises a guide pulley 22 which preferably cooperates with at least one deflection pulley 24, in this case two deflection pulleys. The (freely rotating) deflection pulleys 24 are positioned in the upper part of the frame 12, above the grip pulley 14, to receive the taut strand 20a and deflect it laterally towards the guide pulley 22 which is positioned in the lower part, below and close to the drive pulley 14.
The strand of rope 20a under tension arriving from the top passes via the deflection pulleys 24 to arrive at the guide pulley 22, which further directs the taut strand 20a upwards and transfers it towards the drive pulley 14. The rope 20 then forms a loop around the pulley 14 and exits from the latter behind a clamping pulley 26 which exerts a pressure on the rope 20 towards the bottom of the groove 16.
After the clamping pulley 26, the rope 20 falls downwards by gravity; this is the slack strand 20b. A guide 28 is preferably located directly behind the clamping pulley 26 to guide the rope 20 downwards when it exits from the groove 16. In the present variant, the guide 28 is a square-section channel which is partially open to the side, one end of which is close to the grip pulley 14. The guide 28 preferably comprises a curved finger 30 which extends from the upper end thereof partially into the groove 16 of the grip pulley to facilitate extraction of the rope 20. The guide 28 thus enables extraction of the slack strand 20b out of the winch. There is no need to ballast the slack strand with a weight to extract it from the grip pulley 14.
In such a grip pulley 14 winch, the hauling force depends on the wrap angle of the rope in the groove of the grip pulley and the coefficient of grip of the rope in the groove, as well as on the force exerted by the clamping pulley 26 on exit from the grip pulley. Appropriate sizing of the pulley 14 and of the clamping pulley 26, taking account of the service load, therefore makes it possible to produce a winch which has a sufficient lifting force and does not require an additional brake at standstill. In practice, in accordance with standard EN-1808, the winch is calculated to prevent any rope slippage when raising or lowering a load of greater than or equal to 1.5 times the maximum working load.
In order to improve the grip of the rope in the groove, the walls 31 of the latter are preferably V-shaped. Grip is further increased by protuberances, in this case radial ribs 33 in a staggered arrangement on the opposing sidewalls of the groove 16. As can be seen, the ribs are distributed regularly on each of the sidewalls, and the ribs on one sidewall face the middle of the gap between ribs of the other sidewall.
Grip is further controlled by appropriate groove/rope sizing, the bottom of the groove having a diameter slightly less than that of the rope, for example 0.7 to 0.9, preferably between 0.7 and 0.8, times the diameter of the rope. The aperture angle of the groove (denoted alpha in
Another parameter which influences hauling force is the wrap angle, here denoted E, over which the rope is engaged in the groove 16 of the drive pulley 14. It is the respective positions of the guide pulleys 22 and clamping pulleys 26 which determine said angle □. Angle □ is greater than 200°, preferably greater than 280° and in particular between 300 and 340°. As can be seen in
The various parameters influencing grip will be sized with care since they are also factors in rope wear. Preferably, a wrap coefficient (ratio of wrap diameter to rope diameter) of the order of 14 to 18 with a pulley having a wrap diameter of at least 150 mm will be desirable.
As can be seen in
For an embodiment in the form of an autonomous winch, it will be possible to use an electric motor with which a battery will be associated. This combination forms a compact, easy to use assembly which can be carried by a user. For user safety, the frame is covered, at least on the front face thereof, by a casing with openings for the rope 20.
Reference sign 76 indicates a lug which forms an anchoring point or a support for an anchoring point intended to receive a carabiner or other link by which a user can attach a harness, lanyard or load of some kind. Alternatively, the lug 76 may form an anchoring point for a rigid framework comprising a seat which allows the user to be seated rather than suspended from the winch. A person skilled in the art will furthermore be capable of developing any other solution to form a structure suspended from, or supported by, the present winch.
Certain preferred arrangements may also be stated.
The two deflection pulleys 24 have a stationary rotation pin 32 mounted on the frame and rotate about their respective pins 32 by means of a rolling bearing 34, for example a ball bearing. The pin 36 of the guide pulley 22 (freely rotating) is also stationary in use, but said pulley 22 is mounted retractably by means of an arm 38. The arm 38 therefore bears the guide pulley 22 at one end and is attached pivotably by the other end thereof to the frame 12. In this variant, the arm 38 is made up of a pair of connecting rods 40 which are attached by pin 42 which passes through the frame 12 and receive between them, at the opposite end, the guide pulley 22 which is supported for rotation by a pin 44 and a rolling bearing 46. Under the tension of the rope, the pivot arm 38 moves towards the grip pulley 14. A peg 43 makes it possible to limit displacement of the arm 28 to prevent the guide pulley 22 from coming into contact with the grip pulley 14. In operation, the guide pulley 22 therefore normally has a stationary position. Reference sign 48 indicates a guide part which extends from the pivot 42 of the arm 38 along part of the pulley 14.
The retracted position of the guide pulley 22 (when the peg is withdrawn and arm 38 pivoted back) is illustrated in broken lines on
The pressure exerted by the clamping pulley 26 on the rope 20 is preferably obtained by means of a resilient spring system 50, which makes it possible to avoid adapting the position of the pulley 26 as a function of the diameter and/or state of wear of the rope 20.
According to the present variant, the resilient spring system 50 is based on toggle or articulated lever type mechanisms. The clamping pulley 26 is mounted freely rotating at the end of a clamping arm 56 which pivots relative to the frame 12 (at the lower end of a guide part 57 attached to the frame and which extends along the grip pulley 14 on the opposite side to the guide part 48). The arm 56 comprises a pair of connecting rods 58 which are attached by a pin 60 which passes through the frame 12 and receive between them the guide pulley supported by a pin 52 and a rolling bearing 54.
Reference sign 62 indicates a connecting rod forming an actuating handle, mounted pivotably on the frame 12 about a pin 64 in the upper part of the frame. The arm 56 and the handle 62 are connected by a pair of rods 66 which extend on each side of the frame 12. At the clamping arm 56, the rod 66 is accommodated and axially locked in the rotation pin 52 of the clamping pulley 26. At the handle 62 end, the rod 66 passes through a pivot pin 68, in which it can slide axially. A compression spring 70 is provided on the end of the rods 66, beyond the pivot pin 68. The spring 70 is retained by an axial stop 72, the axial position of which may preferably be set.
Said resilient system 50 therefore makes it possible to retract the clamping pulley 26 for placement of the rope 20, the retracted position being shown in broken lines. The system 50 is locked by pivoting the handle 62 from the retracted position in the direction of the arrow 74. When the pivot pin 68 passes beyond the alignment point of pins 52 and 64, the handle 62 locks. The locking position of the handle 62, and the pressure force exerted by the clamping pulley 26 on the rope 20, may be adjusted by setting the spring force by means of the axial stop 72.
| Number | Date | Country | Kind |
|---|---|---|---|
| 92298 | Oct 2013 | LU | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2014/073034 | 10/27/2014 | WO | 00 |
