FIELD OF APPLICATION
[0001] The present invention relates to a locking pulley for ropes, in particular for climbing
harnesses.
PRIOR ART
[0002] Solutions exist in the prior art for locking pulleys for harnesses that are typically
used to control the descent of a user who is a climber. In particular such locking
pulleys involve the use of a fixed, contrast bushing and a pulley provided with a
locking cam, rotating around an axis of rotation parallel to said contrast bushing.
The contrast bushing and locking cam identify a channel for the passage of the rope
to be held or released based upon the requirements of the user. The locking cam is
provided with a return spring that influences the approach to the contrast bushing
and traction means with which the user may move it away from the contrast bushing
overcoming the action of said return spring. The contrast bushing and the pulley,
provided with a locking cam, are connected to each other by means of a fixed cheek
and a movable cheek, in the form of plates.
[0003] The movable cheek is rotatable together with the pulley so as to be able to move
to an opening configuration adapted to allow the insertion of the rope to be controlled
and/or locked.
[0004] Such known solutions have some disadvantages and limitations.
[0005] For example, some known solutions may open accidentally during use due to the rotation
and/or translation of the movable cheek with the consequent release and lack of control/braking
of the rope.
[0006] In this regard, some safety devices are known, such as for example retainers for
the movable cheek which, once the closing position has been reached, prevent the rotation
of the cheek. Alternatively said known safety devices may prevent the translation
of the safety cheek in an axial direction, i.e., parallel to the extension axis of
the contrast bushing.
[0007] The known devices are not however without drawbacks, in particular they do not prevent
the risk of accidental opening, also because they do not provide any feedback to the
user in relation to the successful and complete closure of said movable cheek.
DISCLOSURE OF THE INVENTION
[0008] The need to solve the drawbacks and limitations mentioned with reference to the prior
art is therefore felt.
[0009] Such need is satisfied by a locking pulley for ropes according to claim 1.
DESCRIPTION OF THE DRAWINGS
[0010] Further features and advantages of the present invention will become more apparent
from the following detailed description of preferred, non-limiting embodiments thereof,
wherein:
[0011] Fig. 1-2 are perspective views, from different angles, of a locking pulley, in an
opening configuration, in accordance with one embodiment of the present invention;
[0012] Fig. 3 is a perspective view of the locking pulley of Fig. 1-2, in a release configuration
of the closure;
[0013] Fig. 4 is a cross-section view of the locking pulley of Fig. 3, in a closing configuration;
[0014] Fig. 5 is an enlargement of the detail V of Fig. 4;
[0015] Fig. 6 is a front view of the locking pulley in accordance with the present invention,
in an initial opening or release configuration of the movable cheek;
[0016] Fig. 7 is a front view of the locking pulley in Fig. 6, in a closing or coupling
configuration of the movable cheek;
[0017] Fig. 8-10 are partial cross-section views and/or with partially transparent elements
of a locking pulley in accordance with the present invention.
[0018] Elements or parts of elements common to the embodiments described hereinafter will
be indicated with the same numerical references.
DETAILED DESCRIPTION
[0019] With reference to the aforesaid figures, an overall view of a locking pulley for
a rope (not shown) is indicated collectively with the numeral 4.
[0020] The locking pulley 4 for ropes comprises a contrast bushing 8 which is cylindrical
in relation to an axial direction X-X. Said contrast bushing 8 is preferably axisymmetric
in relation to said axial direction X-X. The contrast bushing 8 is, for example, made
of a metallic material, preferably aluminum of steel or the alloys thereof.
[0021] The locking pulley 4 furthermore comprises a pulley 12 provided with a locking cam
16 rotatable parallel to said axial direction X-X, for example around a pin 15. The
pulley 12 is usually cylindrical and symmetrical in relation to an axis of symmetry
parallel to said axial direction X-X; the locking cam 16 is typically keyed to the
pulley 12, is integral in rotation with the pulley 12, and is provided with at least
one set of teeth 20 adapted for grasping an associated rope, in a known manner. It
should be pointed out that the pulley 12 and the locking cam 16 may be manufactured
as two parts that are mechanically associated therebetween, or else they may be manufactured
as a single part.
[0022] The contrast bushing 8 and the locking cam 16 identify a channel 24 of variable width
for the passage of a rope to be retained or released according to the needs of a user.
[0023] The locking cam 16 is provided with a return spring 28 which rotatably influences
the approach to the contrast bushing 8 and traction means 32 with which a user may
move it away from the contrast bushing 8 overcoming the action of said return spring
28. The traction means 32 comprise, for example, a simple lanyard or loop, adapted
for being grasped by the user, for example with a finger. The return spring 28 is
typically a torsion/spiral spring.
[0024] The rotation of the locking cam 16 is preferably limited by a pair of end-stops,
for example in the form of pins 33.
[0025] The contrast bushing 8 and the pulley 12, provided with a locking cam 16, are mechanically
connected therebetween by means of a fixed cheek 36 and a movable cheek 40, in the
form of plates.
[0026] In more detail, the movable cheek 40 is integral with the pulley 12 and is rotatable
around a rotation axis parallel to said axial direction X-X from an opening configuration
(Fig. 1-2) adapted to allow the insertion of the rope in which said channel 24 is
maximum, to a closing configuration (Fig. 7) adapted to allow the locking of the rope
in which said channel 24 is minimum.
[0027] The contrast bushing 8 comprises a peripheral groove 44 preferably having a toroidal
shape, axially delimited by an end edge 48 directly facing the movable cheek 40.
[0028] In turn, the movable cheek 40 comprises a coupling portion 52 with a "C" counter-shape
with respect to said peripheral groove 44 so as to make a shape coupling with the
peripheral groove 44 and an undercut in the axial direction X-X. Said undercut limits
the movement of the movable cheek 40 in relation to the fixed cheek 36 in a direction
parallel to said axial direction X-X, as will be better described below.
[0029] Advantageously, said coupling portion 52 comprises a tooth 56 which makes a stop
against the end edge 48 of the contrast bushing 8 when the movable cheek 40 is in
the closed position.
[0030] Preferably, the movable cheek 40, in a closing configuration, is provided with an
axial clearance 60 in the direction away from the fixed cheek 36, said axial clearance
60 being greater than or equal to an axial height 64 of said tooth 56 so as to allow
the movable cheek 40 to be distanced from the fixed cheek 36 and the consequent disengagement
of the tooth 56 from the end edge 48 of the contrast bushing 8 (when the movable cheek
40 is in the closing position). By virtue of such disengagement of the tooth 56 from
the end edge 48 of the contrast bushing 8, it is possible to rotate the movable cheek
40 from the closed position to the open position.
[0031] In accordance with one possible embodiment, said coupling portion 52 comprises an
inlet portion 68 having a radial width 72, perpendicular to said axial direction,
less than or equal to a diameter D of the end edge 48 of the contrast bushing 8.
[0032] Preferably, said inlet portion 68 is asymmetric, having a first radial end 76 provided
with said tooth 56 and a second radial end 80, opposite the first radial end 76, lacking
said tooth 56.
[0033] In accordance with one possible embodiment, the inlet portion 68 comprises lead-in
countersinks 84 for the entry of the coupling portion 52 in said peripheral groove
44.
[0034] In accordance with one possible embodiment, the tooth 56 has an angular width so
that in the step of starting closing or angular overlapping of the movable cheek 40
to the contrast bushing 8, the tooth 56 keeps the movable cheek 40 in an offset position
(Fig. 6) until, upon reaching the complete closing of the movable cheek 40, the latter
may return to a position parallel to the fixed cheek 36 (Fig. 7).
[0035] Preferably, the locking pulley 4 also comprises a return spring 26 configured so
as to axially influence the movable cheek 40 approaching the fixed cheek 36; in other
words the return spring 26 is configured so as to influence the movable cheek 40 in
a position that is substantially parallel to the fixed cheek 36, wherein locking is
permitted between the tooth 56 and the end edge 48 of the contrast bushing 8.
[0036] For example, the return spring 26 is a spiral or cup spring.
[0037] In accordance with one possible embodiment, the fixed cheek 36 and the movable cheek
40 have the same overall dimensions with respect to a projection plane perpendicular
to said axial direction X-X. This configuration is particularly ergonomic for the
user.
[0038] In accordance with one possible embodiment, the fixed cheek 36 and the movable cheek
40 have a central narrowing 88 at said channel 24. Said central narrowing 88 is particularly
comfortable for the user insofar as it may be used to rest the thumb thereon and to
open the movable cheek 40.
[0039] For the purposes of ergonomics, the contrast bushing 8 is hollow, and said fixed
cheek 36 and movable cheek 40, at the contrast bushing 8, are provided with holes
92 aligned with the cavity of the contrast bushing 8.
[0040] Preferably, the fixed cheek 36 and the movable cheek 40 have a peripheral edge 96
cantilevered with respect to the contrast bushing 8: said peripheral edge 96 facilitates
gripping on the part of a user who may thus grasp the movable cheek 40 and move it
axially away from the fixed cheek 36 so as to disengage the tooth 56 from the coupling
portion 52 and open the movable cheek 40. Furthermore, the peripheral edge 96 also
has the function of containing the rope, especially if the latter has a consistent
diameter.
[0041] The operation of the locking pulley according to the present invention will now be
described.
[0042] As mentioned above, in the closing configuration the movable cheek 40 is elastically
influenced towards the fixed cheek 36, in such a way as to ensure the abutment between
the tooth 56 and the coupling portion 52. In such configuration it is not possible
to open the movable cheek 40. If the user intends to open the movable cheek, said
user must first grasp it and move it axially away from the fixed cheek 36: in this
way the tooth 56 is disengaged from the coupling portion 52 and permits the subsequent
rotation of the movable cheek 40 in moving away from the fixed cheek 36. Such slight
movement of rotation/misalignment is indicated by the arrow α in Fig. 6; in the subsequent
Fig. 7 such angle is not shown insofar as it is equal to 0, i.e., the two fixed and
movable cheeks 36,40 are parallel therebetween and perpendicular to the axial direction
X-X. The misalignment or rotation of the movable cheek 40 has to be sufficient to
release the tooth 56 from the peripheral edge 48; in other words, it is necessary
to move the movable cheek 40 away by an amount greater than the axial height 64 of
the tooth 56.
[0043] The closing of the movable cheek 40 is facilitated by the elastic action of the return
spring 28 that influences the movable cheek 40 so as to bring it back into alignment
with the fixed cheek 36, rotating parallel to said axial direction X-X. During this
return movement, the combined action of the return spring 26 and of the shape coupling
between the coupling portion 52 and the tooth 56 permits the elastic snap-return of
the movable cheek 40 to the closing position.
[0044] This snap return, together with a relative acoustic "click," constitutes a further
safety element insofar as it alerts the user, in an unequivocal way, as to the successful
closure of the movable cheek 40.
[0045] As may be appreciated from that which has been described, the present invention overcomes
the drawbacks of the prior art.
[0046] In particular and most importantly, following a clearly audibly noticeable snap,
the user has the certainty of having correctly and completely locked the movable cheek.
[0047] Furthermore the specific configuration of the movable cheek and the end edge of the
contrast bushing makes it possible to make a lock and a shape coupling that prevents
any accidental opening of the movable cheek.
[0048] In fact, as seen, in order to be able to rotate the movable cheek, it is first necessary
to misalign the movable cheek by moving it axially away from the fixed cheek; in this
way the backstop is disengaged from the tooth and permits the subsequent rotation/opening
of the movable cheek.
[0049] This is a safety element that is superior to the solutions of the known art, which
makes any accidental opening of the pulley effectively impossible.
[0050] A person skilled in the art, for the purpose of satisfying contingent and specific
needs, may make numerous modifications and variations to the solutions described above.
[0051] The scope of protection of the invention is defined by the following claims.
1. Locking pulley (4) for ropes, comprising:
- a contrast bushing (8), cylindrical with respect to an axial direction (X-X),
- a pulley (12) provided with a locking cam (16) rotatable parallel to said axial
direction (X-X),
- wherein the contrast bushing (8) and the locking cam (16) identify a channel (24)
of variable width for the passage of a rope to be retained or released according to
the needs of a user,
- the locking cam (16) being provided with a return spring (28) which influences the
approach to the contrast bushing (8) and traction means (32) with which a user may
move it away from the contrast bushing (8) overcoming the action of said return spring
(28),
- wherein the contrast bushing (8) and the pulley (12) provided with locking cam (16)
are mechanically connected to each other by means of a fixed cheek (36) and a movable
cheek (40), in the form of plates,
- wherein the movable cheek (40) is integral with the pulley (12) and is rotatable
around a rotation axis parallel to said axial direction (X-X), from an opening configuration
adapted to allow the insertion of the rope in which said channel (24) is maximum,
to a closing configuration adapted to allow the locking of the rope in which said
channel (24) is minimum,
- wherein the contrast bushing (8) comprises a peripheral groove (44) axially delimited
by an end edge (48) directly facing the movable cheek (40),
- wherein the movable cheek (40) comprises a coupling portion (52) with a "C" counter-shape
with respect to said peripheral groove (44) so as to make a shape coupling with the
peripheral groove (44) and an undercut in the axial direction (X-X),
- wherein said coupling portion (52) comprises a tooth (56) which makes a stop against
the end edge (48) of the contrast bushing (8) when the movable cheek (40) is in the
closed position,
wherein the movable cheek (40), in a closing configuration, is provided with an axial
clearance (60) in the direction away from the fixed cheek (36), said axial clearance
(60) being greater than or equal to an axial height (64) of said tooth (56) so as
to allow the movable cheek (40) to be distanced from the fixed cheek (36) and the
disengagement of the tooth (56) from the end edge (48), when the movable cheek (40)
is in the closing position.
2. Locking pulley (4) according to claim 1, wherein said coupling portion (52) comprises
an inlet portion (68) having a radial width (72), perpendicular to said axial direction
(X-X), less than or equal to a diameter (D) of the end edge (48) of the contrast bushing
(8).
3. Locking pulley (4) according to claim 2, wherein said inlet portion (68) is asymmetric,
having a first radial end (76) provided with said tooth (56) and a second radial end
(80), opposite the first radial end (76), lacking said tooth (56).
4. Locking pulley (4) according to claim 2 or 3, wherein the inlet portion (68) comprises
lead-in countersinks (84) for the entry of the coupling portion (52) in said peripheral
groove (44).
5. Locking pulley (4) according to any one of claims 1 to 4, wherein the tooth (56) has
an angular width so that in the step of starting closing or angular overlapping of
the movable cheek (40) to the contrast bushing (8), the tooth (56) keeps the movable
cheek (40) in an offset position until, upon reaching the complete closing of the
movable cheek (40), the latter may return to a position parallel to the fixed cheek
(36).
6. Locking pulley (4) according to any one of claims 1 to 5, wherein the pulley (4) comprises
a return spring (26) configured so as to axially influence the movable cheek (40)
approaching the fixed cheek (36).
7. Locking pulley (4) according to claim 6, wherein the return spring (26) is a spiral
or cup spring.
8. Locking pulley (4) according to any one of claims 1 to 7, wherein the return spring
(28) is a torsion/spiral spring.
9. Locking pulley (4) according to any one of claims 1 to 8, wherein the fixed cheek
(36) and the movable cheek (40) have the same overall dimensions with respect to a
projection plane perpendicular to said axial direction (X-X).
10. Locking pulley (4) according to any one of claims 1 to 9, wherein the fixed cheek
(36) and the movable cheek (40) have a central narrowing (88) at said channel(24).
11. Locking pulley (4) according to any one of claims 1 to 10, wherein the contrast bushing
(8) is hollow and said fixed cheek (36) and movable cheek (40), at the contrast bushing
(8) are provided with holes (92) aligned with the cavity of the contrast bushing (8).
12. Locking pulley (4) according to any one of claims 1 to 11, wherein said fixed cheek
(36) and movable cheek (40) have a peripheral edge (96) cantilevered with respect
to the contrast bushing (8).