EP4023586A1

EP4023586A1 - A locking element, a pulley with a closure flap locked with the said locking element and a winch with the said pulley

Info

Publication number: EP4023586A1
Application number: EP21202820.3A
Authority: EP
Inventors: Franc Pisek
Original assignee: Pisek Vitli Krpan doo
Current assignee: Pisek Vitli Krpan doo
Priority date: 2020-10-21
Filing date: 2021-10-15
Publication date: 2022-07-06
Also published as: SI26090A

Abstract

The locking element is a plate with two cut-outs for receiving one bolt each, wherein adjacent to the first cut-out an additional opening is provided for installation of spring arranged to be compressed or released with the first bolt installed in the first cut-out, wherein the plate can rotate around the said first bolt. Accordingly, the position of the second bolt in the second cut-out changes, which defines the state of the locking element, i.e., open or closed. In the closed state the first bolt is located in the first cut-out and the spring is extended, while the second bolt in the second cut-out preferably shaped as the letter L is in the shorter leg of the L-shaped cut-out. In the open state upon linear pressure on the side closest to the second cut-out the first bolt compresses the spring and the plate can be rotated around the first bolt, while the second bolt moves in the second cut-out into its other extreme position in the longer leg.

Description

Field of the invention

The present invention belongs to the field of working machines, more precisely to the field of constructional details for locking the position of certain components of said machines. Particularly, the invention belongs to the field of forestry winches and elements needed for pulling a load by winding a pulling rope on a drum. The invention relates to a locking element, a pulley with a closure flap locked with the said locking element and a winch with the said pulley.

Background of the invention and the technical problem

Numerous working machines, particularly forestry winches, use pulleys for guiding a rope with which a load is being pulled. Pulleys usually comprise a housing inside which a sheave that is freely rotatable around a central axis is provided. A rope runs on the sheave, said rope winding and unwinding from the winch drum. The bottom pulleys, for example, serve to lower the centre of gravity of the winch during load pulling and represent an important part of the winch, which enables reliable load pulling. Due to their occasional use, the lower pulleys have to be quickly and simply prepared for use, i.e., the pulley has to be easily opened, the rope then is inserted and afterwards the pulley is closed. The inserted rope has to be reliably hidden in the housing of the pulley. For this purpose, several different safety elements for protection of the rope in bottom pulleys have been developed, however, these solutions have certain disadvantages particularly related to simplicity and use ergonomics.
The present invention is based on the solution described in Slovenian patent application P-202000089, which discloses a bottom pulley with a closure flap, comprising at least a pulley housing, inside which a freely rotatable sheave for guiding the rope is installed in an axis, and a closure flap, which is mounted with a pinion of the pulley, said pinion enabling movement of the pulley when installed on the winch, or the closure flap is mounted on a hinge on the housing of the pulley, wherein the closure flap has an open and a closed state, between which switching is enabled with a locking pin. The locking pin, as described in this document, is not optimal when in use, therefore the technical problem, which is solved by the present invention, is a constructional design of an alternative locking element that will reliably and in a user-friendly manner enable locking and unlocking of the position of the closure flap. The aim of the invention is also universality of the locking element, so that it can be used in other components and machines, not only on pulleys for forestry winches.

Prior art

With the aim of preventing unwanted disengagement of the rope a safety mechanism has been developed, the said safety mechanism comprising a pin installed through openings on the both sides of the pulley housing, wherein the pin covers a diameter larger than the diameter of the sheave. Control of the pin is ensured with a stem equipped with a compression spring and a restrictor. The problem of this design is in that the stem with the spring and the restrictor protrudes from the housing, due to which the safety mechanism can deform and cease to optimally operate.
The above-mentioned problem has been solved with a solution according to patent SI 22796 , wherein the safety mechanism comprises at least a pin and a stem with an integrated spring, which are firmly interconnected. The pin can be past the pulley inserted through the coaxial openings, which are at corresponding locations available in the mutually displaced walls of the housing, while through the specified walls an axis is running through the freely rotating pulley. The stem is rigidly connected to the aforementioned pin, which can be shifted in the direction of its longitudinal axis from the position of fitting the aforementioned openings in the walls of the housing to the position of fitting only one opening in the wall against the spring force, which is during this supported against the corresponding wall of the housing. The stem is on its free end inside the housing equipped with a restrictor, wherein the step is parallel to the pin and inserted through openings in the corresponding wall on that side of the housing, which the pin can be moved to against the force of the aforementioned spring, while the specified stem with the pin is firmly connected via a link located outside the housing. This solution differs from the present invention in the construction of the closure flap and the locking element.
Patent SI 24806 describes a guard that combines the function of a closure flap and a locking element. Said guard is rotatably mounted in the pivot of a vertical carrier of the lower pulley and has a spring-supported control button, which is in the locked position located in a cut-out, while upon pressure on the control button, the latter is lowered and thus dislocated from the cut-out, which enables movement of the guard into the open position. The construction of the locking element according to the invention differs from the solution described in SI 24806 .

Description of the solution to the technical problem

The technical problem is solved as described in the independent claim, while the preferred embodiments of the solution are described in dependent claims.
The locking element is shaped as a plate with two cut-outs arranged to receive two bolts, which are arranged to be installed in a hole provided in the element which will be opened and closed with the said locking element, preferably in the closure flap of a lower pulley for forestry winches. Adjacent to one of the cut-outs an additional opening is provided, said opening being arranged for receiving a spring, which can be compressed or released by the bolt installed in this cut-out, as it is from the direction of the second cut-out limited by the end of the first cut-out and on the other side with the first bolt. Depending on the position of the latter, the spring may be compressed or released. In agreement with this status change related to the spring, the position of the second bolt in the second cut-out changes, because the position of the plate is altered due to its rotation around the first bolt. The first (upper) bolt functions so that the first movement (i.e., compression of the spring) is performed linearly, while afterwards the said bolt functions as a fulcrum of the locking element. The second (lower) bolt is arranged to define the initial and the end position of the locking element and that the locking element can snap in place due to the action of the installed spring. Said spring may be any suitable spring, preferably it is a compression spring, as it can be fully integrated in the interior and can be limited from the direction of the second cut-out with a solid closed end of the first cut-out and on the other side with the first bolt.
The shape and position of the cut-outs for bolts in the plate is arbitrary, as long as it enables the above-described movements, wherein the first cut-out is preferably oval and the second cut-out is preferably shaped as the letter L with a longer and a shorter leg, wherein both legs may also have the same length. The angle between the legs is arbitrary, while the preferred angle is approximately 90°. The second bolt can be located in both extreme positions of the second cut-out, when the locking element is locked or unlocked, respectively. The first bolt has extreme positions in both ends of the oval cut-out. The shape of the plate is arbitrary, preferably in the shape of a thickened (widened) letter L, wherein the plate has a narrower part which expands into a wider part in which the second cut-out is arranged. The first cut-out is provided in the narrower part of the plate. The first leg of the second cut-out is preferably in the same line as the first cut-out and continues into the second leg via an angled section between both legs. The locking element can firstly perform a linear movement by moving the first bolt from one extreme position to the second, while in the next movement the plate is rotated around the first bolt functioning as a fulcrum of the locking element.
Instead of bolts any other suitable elements may be used, such as a swivel pin (kingpin), a rivet, a pin, a dowel or similar, however, the optimal choice fo the required function are bolts. The size of the bolts or other elements is chosen with regards to the size of cut-outs and the plate as well as its thickness. The dimensions of the locking element also depend on the element, which will be locked or unlocked with the locking element.
Further description of the invention will be based on the basis of a preferred embodiment of the locking element, which comprises:

the base plate having two cut-outs each arranged to accept one bolt, wherein the first cut-out is oval shaped and the second cut-out is shaped as a letter L with a longer leg and a shorter leg, wherein the shorter leg of the second cut-out is under the first cut-out in the same line,
two bolts arranged to be installed in the said cut-outs, wherein the bolts are intended to define the position of the locking element and for installation of the locking element to an element to be controlled by the locking element according to the invention, wherein the first bolt in one of the extreme positions in the first cut-out functions as a fulcrum of the whole locking element,
one additional hole near the first cut-out arranged to receive a spring, and
the spring arranged to be compressed with the first bolt, when said first bolt is installed in the first cut-out.

Below described functioning method is the same or similar also for other possible embodiments of the invention.
The locking element has a closed and an open state, which can be changed by pushing on one of the sides of the plate, wherein:

in the closed state, the first bolt in the first cut-out near the spring is in its extreme position, which allows an extended state of the spring, while the second bolt in the second cut-out shaped as the letter L is in the extreme position in the shorter leg of the second cut-out;
in the open state upon application of linear pressure to the side of the plate closest to the second cut-out the first bolt compresses the spring and the plate is moved, so that the first bolt is in its other extreme position and rotation around the first bolt is possible, so that the second bolt in the second cut-out moves into the second extreme position in the longer leg of the second cut-out, wherein the plate of the locking element is in a position that allows movement of the element, which was previously locked with the locking element in the closed state. In this position, the spring is compressed and allows maintenance of the position of the plate. Additionally, the optional deepened end of the longer leg of the second cut-out further retains the bolt in its extreme position.

Operation of the locking element thus depends on the pressure to the plate in the direction of the spring axis, said pressure resulting in the spring being compressed by the first bolt, wherein the position of the second bolt is changed from the position in the shorter leg into the position in the longer leg of the second cut-out. When the locking element is required to be opened or unlocked, the plate has to be pushed in the direction of spring compression and rotated around the first bolt. When the locking element is pulled towards the user, the spring is released and the locking element self-snaps due to the action of the spring and movement of the second cut-out with regards to the second bolt.
The advantage of the described solution is in that during unlocking of the locking element according to the invention, said locking element is pushed in the direction of spring compression, so that the second bolt is not in the extreme position in the shorter leg of the second cut-out, which is then followed with a rotation into one direction, which prevents the locking element from self-opening due to vibration or other events. When the locking element is required to be locked, it is advantageous that the locking element is pushed so that the position of the second bolt is moved from the extreme position in the longer leg and rotated, consequently leading the locking element to self-snap due to the compression spring. The direction in which the plate is rotated depends on the shape of the locking element and the cut-outs.
One of the possible alternative embodiments of the locking element according to the invention as described above, is elimination of the spring and the hole for the installation of the spring, as fixation of the closure flap in the required position (open or closed) could be achieved with any suitable pin or a similar element. In this embodiment, a pin hidden below the plate and installed on the housing of an element to be locked by the locking element would ensure maintenance of the rotated position of the plate, as the pin would engage in an opening and prevent further movement of the plate. In case rotation into the initial position is required, the user can press the pin downwards and rotate the plate. It is also possible to arrange the pin to operate vice-versa or any other alternative obvious to a skilled person.
A second possible alternative embodiment of the locking element as described above is to perform only the linear or only the rotating movement. In the first case, the spring is present, while the position of the linearly displaced plate would be locked with a pin or a similar element. In case of sole rotating movement, the second cut-out for the bolt should be shaped as a curve displaced from the centre of the fulcrum.
Although the presented alternative embodiments solve the technical problem, the embodiment as described above is preferred as it enables simple, reliable and user-friendly locking of any element.
The described embodiments of the locking element may be used for locking position of any element, particularly for pulleys of different machines, among which forestry winches are most important, as the lower pulleys of winches are not continuously used, but have to be occasionally opened and closed in order to install the pulling rope. In order to control or change the status of a particular element, the locking element is installed on the element, preferably the locking element is installed on the housing of a pulley, in particular a lower pulley installed or intended for use in forestry winches.
The pulley with the closure flap and the locking element according to the invention comprises at least a housing, inside which a freely rotatable sheave is installed in an axis, said sheave being arranged to lead the rope. The housing of the pulley is movably installed on a winch or any other suitable device for pulling a load with a pulley. The closure flap is installed via a bushing and a pinion, which allow movement of the pulley when it is installed on the winch, which means that a circular movement of the bottom pulley and the closure flap is the same. Alternatively, the closure flap may be installed in a fulcrum (hinge) on the pulley housing, but the installation via the bushing and the pinion is far simpler and more economic. The closure flap is preferably shaped as a right-angled triangle having a curved hypotenuse arranged to correspond to the shape of the sheave. This shape covers the essential part of the housing with the sheave, which prevents the rope from falling out or any damage to the rope. Said flap has an open and a closed state, switching between which is allowed with the locking element according to the invention and/or exemplary embodiment.
The pulley of the housing is provided with suitable holes for installation of the locking element, said holes being arranged so that in closed and locked state of the locking element the latter covers at least a part of the housing of the pulley and the closure flap. In the open and unlocked state of the locking element, the latter does not cover the closure flap, which is consequently free and a rope can be installed through the gap between the housing and the flap. The pulley housing has two holes for installation of both bolts of the locking element. Firstly, through the opening for the spring, the spring is installed, and then through the first cut-out and the first hole in the pulley housing the first bolts in installed. In the second cut-out and through the second hole in the pulley housing the second bolt is installed. When pressure is applied to the locking element in the direction of the spring axis, the locking element can be moved, as the spring is compressed and the positions of both bolts is changed, particularly the position of the second bolt in the second cut-out enables that the extreme position in the longer leg of the second cut-out is maintained. When the locking element is pushed in the direction towards the second bolt, the plate is moved so that the second bolt returns to its initial position in the shorter leg of the second cut-out, while the first bolt releases the spring. When the closure flap is locked on the housing of the bottom pulley with the described locking element, the pulley and the flap move together as one unit. When the closure flap is not fixed with the locking element, the flap can move independently from the pulley. By moving the locking element according to the invention, the position of the closure flap is easily controlled, wherein none of the element is essentially protruding outside the pulley housing. This construction allows faster and easier installation or removal of the rope into the bottom pulley, while the gap is closed along the whole height of the pulley, so that the rope cannot leave the pulley or fall out from it. Safe and reliable use of the pulley or a device on which such pulley is installed is thus possible. The shape of the plate of the locking element and the shape of the cut-outs defines the direction of the rotation, which is for unlocking of the closure flap towards the bushing of the pulley or away from the bushing of the pulley.
The described pulley may be installed on any working machine, preferably on a forestry winch having one or several drums for winding/unwinding the pulling rope.
Alternatively, the locking element itself may function as the closure flap on the described pulley, wherein the locking element has to have dimensions suitable to cover the gap between the housing of the pulley and the bushing of the pulley, which together with a pinion enables installation to the housing of the winch, so that in closed state with installed rope the locking element prevents the rope from falling out from the pulley. In this case the locking element is designed in the same way as described above and is mounted on the housing of the pulley. The pulley with the locking element which replaces the closure flap, has an open and a closed state and comprises at least:

the base plate having two cut-outs each arranged to accept one bolt, wherein the first cut-out is oval shaped and the second cut-out is shaped as a letter L, wherein the base plate covers the opening between the pulley housing and the pulley bushing, which via a pinion of the pulley enables installation of the pulley to the winch,
two bolts arranged to be installed in the said cut-outs, wherein the bolts are intended to define the position of the locking element and for installation of the locking element to the housing of the pulley,
one additional hole near the first cut-out arranged to receive a spring, and
the spring arranged to be compressed with the first bolt, when said first bolt is installed in the first cut-out, wherein the base plate can rotate around the first bolt, so that the second bolt is moved from its first extreme position to the second extreme position in the second cut-out, wherein movement of the plate and opening of a gap between the housing and the bushing is allowed, said spring allowing the return movement from the open to the closed state.

In the scope of the invention several different variants of the locking element obvious to a skilled person are possible, which does not limit the essence of the invention as described herein and defined in the claims.
The locking element installed on a pulley with a closure flap will be described in further detail based on an exemplary embodiment and figures, which show:

Figure 1: An explosion view of the locking element and the pulley with the closure flap
Figure 2: An elevation view of the pulley with unlocked locking element and open closure flap
Figure 3: An elevation view of the pulley with locked locking element and closed closure flap

Figure 1 shows an explosion view of the locking element 3 and the pulley with the closure flap 2, wherein the locking element 3 comprises at least:

the base plate 31 with a narrower part 31a and a wider part 31b, wherein the plate 31 has two cut- outs 32a, 32b each arranged to accept one bolt 33a, 33b, wherein the first cut-out 32a is located in the narrower part 31a of the plate 31, while the second cut-out 32b is located in the wider part 31 b of the plate 31,
two bolts 33a, 33b arranged to be installed in the said cut- outs 32a, 32b, wherein the bolts 33a, 33b are intended to define the position of the locking element 3 and for installation of the locking element 3 to an element to be controlled by the locking element, which is according to the exemplary embodiment a pulley with a closure flap 2,
one additional hole 34 near the first cut-out 32a arranged to receive a spring 35, and
the spring 35 arranged to be compressed with the first bolt 33a, when said first bolt 33a is installed in the first cut-out 32a.

The preferred embodiment of the pulley with the unlocked locking element and the open closure flap is shown in figure 2, while figure 3 shows the same preferred embodiment wherein the locking element is locked and the closure flap is closed. The pulley comprises at least:

housing 1, inside which a freely rotatable sheave for leading a rope is installed;
a bushing 11 of the pulley for installation on a forestry winch or a similar machine, wherein the said bushing 11 is installed rotatably around a pinion of the pulley;
a closure flap 2 installed via the bushing 11, wherein the flap 2 has an open and a closed state, switching between which is possible with the locking element 3,

locking element

a base plate 31 having two cut- outs 32a, 32b each arranged to receive one bolt 33a, 33b,
two bolts 33a, 33b arranged to be installed in said cut- outs 32a, 32b and holes 12a, 12b in the housing 1 of the pulley, wherein the bolts 33a, 33b are intended for defining the position of the locking element 3 and for installation of the locking element 3 on the pulley; and
one additional hole 34 near the first cut-out 32a for installation of the spring 35, and
a spring 35 arranged to be compressed with the first bolt 33a, when the latter is installed in the first cut-out 32a,

element

in the closed state, the first bolt 33a in the first cut-out 32a near the spring 35 is in its extreme position, which allows an extended state of the spring 35, while the second bolt 33b in the second cut-out 32b shaped as the letter L is in the extreme position in a shorter leg 32b' of the second cut-out 32b;
in the open state upon application of linear pressure to the side of the plate closest to the second cut-out 32b the first bolt 33a compresses the spring 35 and the plate is moved, so that the first bolt is in its other extreme position and rotation around the first bolt is possible, so that the second bolt 33b in the second cut-out 32b moves into the second extreme position in a longer leg 32b" of the second cut-out 32b, wherein the plate of the locking element is in a position that allows movement of the closure flap, which was previously locked with the locking element in the closed state.

When the locking element 3 is pressed or pushed in the direction of the spring 35 or its axis, respectively, the locking element 3 may be moved as the spring 35 is compressed, while the positions of both bolts 33a, 33b in cut- outs 32a, 32b are changed, particularly the position of the second bolt 33b in the second cut-out 32b allows that the second extreme positions of the locking element 2 is maintained. When the locking element 3 is pushed in the direction towards the second bolt 33b, the plate 31 is moved so that the second bolt 33b returns to the second extreme position in the second cut-out 32b, while the first bolt 33a releases the spring pa 35. When the closure flap 2 is attached to the housing 1 of the bottom pulley with the locking element 3, the pulley 1 and the closure flap 2 move as one entity. When the closure flap 2 is not fixed with the locking element 3, it can move independently from the movement of the pulley 1. The direction rotation depends on the shape of the plate of the locking element and the shape of the cut-outs, wherein for unlocking of the closure flap the movement may either be towards the bushing of the pulley or away from the bushing of the pulley, as shown in figures 2 and 3.

Claims

A locking element having a closed and an open state, comprising at least:
- the base plate having two cut-outs each arranged to accept one bolt, wherein the first cut-out is preferably oval shaped and the second cut-out is shaped as a letter L,

- two bolts arranged to be installed in the said cut-outs, wherein the bolts are intended to define the position of the locking element and for installation of the locking element to an element to be controlled by the locking element,

- one additional hole near the first cut-out arranged to receive a spring, and

- the spring arranged to be compressed with the first bolt, when said first bolt is installed in the first cut-out, wherein said spring enables return movement from the closed and the open state.
The locking element according to claim 1, characterized in that it has a closed and an open state, wherein:
- in the closed state, the first bolt in the first cut-out near the spring is in its extreme position, which allows an extended state of the spring, while the second bolt in the second cut-out shaped as the letter L is in the extreme position in a shorter leg of the second cut-out;

- in the open state upon application of linear pressure to the side of the plate closest to the second cut-out the first bolt compresses the spring and the plate is moved, so that the first bolt is in its other extreme position and rotation around the first bolt is possible, so that the second bolt in the second cut-out moves into the second extreme position in a longer leg of the second cut-out, wherein the plate of the locking element is in a position that allows movement of the element, which was previously locked with the locking element in the closed state.
The locking element according to any of the preceding claims, characterized in that the shape of the plate is arbitrary, wherein the preferred shape of the plate is a shape of a thickened letter L having a narrower part extending into a wider part.
The locking element according to the preceding claim, characterized in that the narrower part is provided with an oval first cut-out and the wider part is provided with a second cut-out that has the shape of a lying letter L, wherein one leg is below the oval cut-out and in the same line as the said oval cut-out.
The locking element according to the preceding claim, characterized in that the legs of the second cut-out have the same or a different length, wherein the angle between both legs of the second cut-out is preferably from 75° to 105°, most preferably 90°.
The locking element according to claim 1, characterized in that the second cut-out is curved.
A locking element having a closed and an open state, comprising at least:
- a base plate having two cut-outs each arranged to accept one bolt, wherein the first cut-out is preferably oval shaped and the second cut-out is shaped as a letter L,

- two bolts arranged to be installed in the said cut-outs, wherein the bolts are intended to define the position of the locking element and for installation of the locking element to an element to be controlled by the locking element,

- a pin or a similar element for fixation of the locking element in a required position, i.e., open or closed, wherein the pin is hidden under the plate and installed to a housing of the element locked by the locking element, wherein said pin is arranged to be ejected upon movement of the locking element, thereby preventing movement of the plate, wherein in case of return movement the pin is arranged to be compressed so that plate can be moved.
A pulley with a closure flap, characterized in that open and closed state of the closure flap is defined with the locking element according to any of the preceding claims.
The pulley according to the preceding claim, characterized in that the pulley comprises at least a housing, inside which a freely rotatable sheave for leading the rope is installed on an axis, wherein the said housing is movably mounted on a winch or any other suitable device for pulling a load, and in that the closure flap is installed with a bushing and a pinion of the pulley or in a fulcrum on the housing of the pulley, wherein said closure flap is preferably shaped as a right-angled triangle and its hypotenuse is curved to correspond to the shape of the sheave or the housing of the pulley, respectively, thus covering the essential part of the housing with the sheave, which prevents dislocation of the rope from the sheave or even rupture of the rope.
The pulley according to any claim from 8 to 9, characterized in that the housing of the pulley is provided with suitable holes for installation of the locking element, said holes being position so that in the locked state of the locking element the latter covers the housing of the pulley and the closure flap, while in the unlocked state of the locking element the latter does not cover the closure flap.
The pulley with the closure flap according to the preceding claim, characterized in that it is provided with a through-hole for receiving a spring, said hole being adjacent to the first cut-out, wherein through the first cut-out and the first hole in the pulley housing the first bolt is installed, through the second cut-out and the second hole in the pulley housing the second bolt is installed, wherein the spring is arranged to be compressed with the first bolt upon applied pressure to the locking element in the direction of the spring axis, and wherein the first bolt functions as a fulcrum of the plate, and the position of the second bolt in the second cut-out enables that the open state of the locking element is maintained, and wherein the locking element is arranged to be pushed in the direction towards the second bolt, in order to allow return of the second bolt into the second extreme position in the second cut-out and the first bolt releases the spring, thereby moving the locking element into the closed state.
The pulley with the closure flap according to any claim from 8 to 11, characterized in that the housing of the pulley is movably mounted on a winch or any other device arranged to pull a load with a pulling rope via the pulley.
The pulley with the closure flap according to any claim from 8 to 12, characterized in that the pulley is a lower pulley of a forestry winch.
A pulley with a locking element arranged to function as a closure flap, characterized in that the locking element has an open and a closed state and comprises at least:
- a base plate having two cut-outs each arranged to accept one bolt, wherein the first cut-out is oval shaped and the second cut-out is shaped as a letter L with a longer leg and a shorter leg, wherein the base plate covers a gap between the pulley housing and the pulley bushing, which with a pinion enables attachment of the pulley to the winch housing,

- two bolts arranged to be installed in the said cut-outs, wherein the bolts are intended to define the position of the locking element and for installation of the locking element to the pulley housing,

- one additional hole near the first cut-out arranged to receive a spring, and

- the spring arranged to be compressed with the first bolt, when said first bolt is installed in the first cut-out,

- the spring arranged to be compressed with the first bolt, when said first bolt is installed in the first cut-out, wherein the base plate can rotate around the first bolt, so that the second bolt is moved from its first extreme position to the second extreme position in the second cut-out, wherein movement of the plate and opening of a gap between the housing and the bushing is allowed, said spring allowing the return movement from the open to the closed state.
A forestry winch with the locking element and/or the pulley according to any of the preceding claims.