EP3915930A1

EP3915930A1 - Warning device and forestry winch with said device

Info

Publication number: EP3915930A1
Application number: EP21174631.8A
Authority: EP
Inventors: Franc Pisek
Original assignee: Pisek Vitli Krpan doo
Current assignee: Pisek Vitli Krpan doo
Priority date: 2020-05-22
Filing date: 2021-05-19
Publication date: 2021-12-01
Also published as: AT17928U1; DE202021004075U1; SI26004A

Abstract

The invention relates to a warning device for signalling limited amount of a pulling rope on a winch drum and to a forestry winch comprising the said device. The warning detects the distance between the drum and an element, which ensures optimal winding of the rope onto the drum (5), which is indicative for remaining layers of the rope on the drum, wherein detection is enabled with at least one switch, sensor or any other element, which can detect the said distance. The warning comprises a pushing cylinder (1), a signalling device (3), which is arranged to emit a sound and/or a visual signal, and at least one sensor, switching device or any other element (2), which can detect the distance between the pushing cylinder and the drum and which can create a signal to the signalling device to warn about the limited amount of rope on the drum.

Description

Field of the invention

The invention belongs to the field of forestry winches, more precisely to the field of constructional details in forestry winches, which are connected with pulling of a load by winding a rope onto a drum via a pulley. The invention relates to a warning device for signalling limited amount of a pulling rope on a winch drum and to a forestry winch comprising the said device.

Background of the invention and the technical problem

Use of a winch may lead to a situation when safe and reliable interruption or termination of unwinding of a rope from a drum is required due to a limited amount of the rope remaining on the drum. It is common that the user fails to timely terminate unwinding or the user keeps driving the tractor for too long, which leads to lack of rope and consequently the rope is teared out from the drum, thus leading to sudden and unexpected release of tension. In this case, the rope or steel rope has to be reinstalled into the drum, which requires removal of protective tin plates and machine parts. In the worst-case scenario other constructional elements, for example the guide of the wire rope or any piece of the drive (chains, sprockets, lamellae, etc.), may be damaged. In consequence, work has to be stopped and often the rope and/or any other damaged piece have to be replaced due to severe deformation. In case the rope is torn out from the drum during work on a steep slope, the load may slide down the slope and cause significant damage. In addition, it may also put people present on the slope in danger.
Usual standards dictate that at least three coils of rope have to remain on the drum at all times, while some other sources recite that at least eight coils on the rope have to be present. This condition is hard to follow, by feeling or by viewing. The technical problem, which is solved by the present invention, is a constructional solution of a warning device that will signal the user that the amount of the wire rope on the drum, preferably forestry winch drum, is limited.

State of the art

Patent US7097155 describes a method and apparatus for indicating when only a given minimum pre-set number of winding layers are present on a drum of a winch. The winch comprises a winding drum, onto which the rope is wound or from which the rope is unwound, drive means for rotating the drum in both directions and an indicator for displaying an alarm when the sensor detects a minimum number of rope layers remaining on the drum. An optical sensor system is included in a space in a hollow housing to count the number of revolutions of the drum and the direction of rotation to produce an alarm signal
Patent application US2019023542 discloses methods and systems are provided for adjusting operation of a motor of a winch, wherein this is enabled with a control unit, which follows the temperature of the motor, load of the motor, distance between the drum and the end part of the rope and optionally also the amount of rope on the drum. The latter is enabled with a position sensor on the drum or drive shaft of the motor. By counting the number of drum rotations and the thickness of the rope and the diameter of the drum, the control unit can estimate the distance from the drum axis to the outermost layer of the rope wound on the drum, which is representative for the amount of remaining rope on the drum.
A 40-tone winch for use on ski slopes and similar slopes is known, that is sold under the trademark PistenBully and is described on the website: https://www.pistenbully.com/en/vehicles/attachments/winch/accessactn/show/acateg ory/winch/accessorv/40-ton-winch.html. The winch has a display, which displays the amount of remaining rope on the drum, however the description is silent about measurement of the amount of the remaining rope. In connection with a similar winch, patent EP 2 554 750 B1 has been granted, the said patent describing a method of following use of a winch and determination of wear of the rope. For this purpose the winch is equipped with a number of sensors, one of which is dedicated to follow the length of the remaining rope on the drum. This sensor follows rotation of the drum during unwinding and winding, wherein for the final calculation of the remaining rope the whole length of the rope and the drum dimensions have to be known.
The solution described in document JPH0642004 also follows the amount of remaining rope on the drum by tracing rotations thereof.
All above-described solutions are based on following rotation of the drum; therefore, they significantly differ from the present invention.

Description of the solution of the technical problem

The invention is not based on following rotation of the winch drum, but on sensing the distance between the drum and a pushing cylinder, which ensures optimal winding of the rope onto the drum, which is indicative for the remaining layers of rope coils on the drum. Sensing is enabled by an inductive sensor or switch, or any other sensor or element that can sense the mentioned distance. The technical problem is solved with the warning device according to the independent claim, while preferred embodiments of the solution are described in dependent claims.
The present invention is based on a solution of a drum for a forestry winch described in patents SI 24995 and SI 24996 . The drum of the winch is provided with a pushing cylinder installed on forks, which oscillate around their mounting, wherein tension of the pushing cylinder is ensured with a spring or any other suitable element. The spring, which through forks pushes the cylinder, may be a tension, compression, torsion or gas spring. Preferably the springs are two and are installed on the handle of the pushing cylinder and the housing of the winch. Said spring pulls the forks and pushes the pushing cylinder to the drum with the wound rope, thereby ensuring improved winding of the rope onto the drum and preventing uncontrolled unwinding of the wire rope. The pushing cylinder is upon winding a new layer of the rope removed farther away from the drum, thereby rotating the axis of the forks carrying the pushing cylinder. By winding the rope onto the drum, the diameter of the rope layers increases, while the pushing cylinder consequently moves farther away from the drum as the forks rotate around their mounting. In case of unwinding of the rope, the pushing cylinder draws nearer to the centre of the drum.
The essence of the invention is in that on the housing of the winch or preferably on the pushing cylinder, more preferably on the holder of the pushing cylinder, a switch, sensor or any other element that is arranged to sense the distance between the pushing cylinder and the drum is installed. The preferred element is an inductive switch, but an optical sensor, an electric switch, a magnet or a capacitive sensor and similar may also be used. Instead of the pushing cylinder any other element for uniform winding of the rope onto the drum may be used, for example a sliding plate, preferably made from a softer material such as bronze or plastic, so that it does not damage the rope. The pre-set distance for signalling depends on the thickness of the rope on the drum as well as on the dimensions of the pushing cylinder and connected constructional elements. However, in usual cases the distance is set to 3 to 8 mm, which satisfactorily covers all proportional dimensions equivalent to the last layer of rope wound on the drum. The height of the inductive switch (sensor), that is preferably mounted on an accessory, can be adjusted in order to allow setting of the required distance needed for signalling of the limited amount of rope on the drum. In this way the warning device can be adjusted to different standards used in the world. At least one signalling element or a sensor must be present, but it is possible to install two, in order to ensure more reliable operation in case one of them fails or ceases to function correctly.
The switch or the sensor is arranged to automatically switch off or preferably to signal the user via a signalling device that a manual turning off should be performed. The connection between the signalling device and the switch or the sensor, preferably inductive sensor, may be an electric wire that:

sends a signal to the signalling device which warns the user, or
sends a signal to the motor, which automatically terminates winding of the rope.

However, the connection may be electronic, electrical of mechanic, depending of the type of sensor or switch and the position of the signalling device or to a switching element, which may be a hydraulic valve mechanically connected to a handle on the lever system to which the pushing cylinder is attached.
The switch upon its activation causes transmittance of a signal via the signalling device, which is installed on the housing of the winch, preferably in higher parts of the housing, so that its visibility is the best possible. The signalling device may be a sound, light or combined (sound + light) signalling device, thus warning the user with a sound alarm, a light signal or a combination of a sound alarm with a light signal. Once only one layer of rope coils remains on the drum, the inductive sensor triggers a signal to warn the user about the limited amount of the wire rope.
The warning device in its preferred embodiment comprises three key elements, namely:

the pushing cylinder, wherein its position with regards to the drum is indicative for the layers of rope remaining on the drum,
the switching device and/or a signalling device, which emits a sound and/or a visual signal upon activation of the sensor or a switch, and
the sensor, switch or any other element that can detect the distance between the pushing cylinder and the drum, and can generate a signal to the signalling device or a signal that causes termination of unwinding of the rope.

Operation of the warning device according to the invention is carried out in the following way. During unwinding of the rope from the drum the pushing cylinder is moved closer to the centre of the drum. When the pushing cylinder reaches the pre-set distance, the inductive sensor senses this event and triggers sending of a signal to the signalling device. The signal can be detected by the user, who can then terminate the process of rope unwinding in any known manner. Alternatively, termination of the rope unwinding can be achieved automatically, wherein upon activation of the switch or the sensor unwinding is automatically stopped due to a mechanical connection using suitably shaped handles or levers, or due to a direct turning off of the drum drive. In the latter case, activation of the switch or the sensor causes switching of the state of hydraulic or electric circuit of the drum, i.e. from status on to status off.
Construction of the warning device according to the invention does not prevent the rope from being torn out from the winch in case this is necessary due to safety.
The warning device for signalling limited amount of pulling rope on the winch drum and the winch comprising the warning device will be described in continuation based on exemplary embodiments and figures, which show:

Figure 1: A forestry winch with the warning device according to the invention
Figure 2: Detail A of a possible location of the signalling warning device
Figure 3: Detail B of the position of the inductive switch with the drum, which is partly cut
Figure 4: Position of the inductive switch with the whole drum

Figure 1 shows a forestry winch with marked up key components, which enable required operation of the invention, wherein the winch is equipped with a drum 5, to which a pulling rope is wound or unwound. The drum 5 is provided with a pushing cylinder 1 installed on forks, which oscillate around its mounting, wherein the tension of the pushing cylinder is enabled by two springs 4, which is installed on a handle of the pushing cylinder 1 and housing of the winch. Said spring pulls the forks and pushes the pushing cylinder 1 onto the drum 5 and consequently the rope. An inductive sensor 2 is installed on the pushing cylinder 1. The housing of the winch is on a visible part provided with a signalling device 3, which can warn the user with a sound and/or light signal, thus signalling a limited amount of rope is available, i.e. only the last layer of rope coils is present on the drum. The signalling device 3 may be installed anywhere on the housing of the winch, preferably it is provided in higher parts, so that the user can easily see and/or hear the signal.
Figure 2 shows the detail A in figure 1, where one of the possible locations of the signalling device 3 is depicted.
Detail B, which is shown in figure 3, clearly defines the construction of the warning device and elements, which are essential for its functioning. The warning device according to a possible embodiment comprises three key elements, which are:

the pushing cylinder 1, which ensures suitable winding of the rope onto the drum using the spring 4, wherein the position of the pushing cylinder 1 with regards to the drum 5 is indicative for the remaining layers of rope coils on the drum 5,
the signalling device 3, which emits a sound and/or visual signal upon activation of the sensor or the switch 2, and
the sensor, switch or any other suitable element 2, which can detect the distance between the pushing cylinder 1 and the drum 5 and which can create a signal shown by the signalling device 3.

The preferred embodiment of the sensor is an inductive sensor 2, which is triggered at a certain distance of the pushing cylinder 1 and drum 5, usually between 3 and 8 mm, which depends on the thickness of the rope. It is important that the sensor is triggered at the latest when one layer of rope is present on the drum. Instead of creating a signal for the signalling device 3, the sensor 2 may trigger termination of the rope unwinding automatically. Said termination is arbitrary, for example upon activation of the switch or the sensor unwinding is automatically stopped due to a mechanical connection using suitably shaped handles or levers, or due to a direct turning off of the drum drive. In the latter case, activation of the switch or the sensor causes switching of the state of hydraulic or electric circuit of the drum, i.e. from the on state to the off state
The inductive sensor 2 is through an accessory 21 screwed onto the holder (fork) 11 of the pushing cylinder 1. The whole stem is provided with a thread, so that it can be set using at least one, preferably two nuts, wherein one is below and the other is on top of the sheet metal. With the accessory 21 designed in such way the required distance needed for the sensor to detect and send an electric signal to the signalling warning device 3 can be adjusted.

Claims

A warning device for signalling a limited amount of a pulling rope on a winch drum, characterized in that it detects the distance between the drum and an element, which ensures optimal winding of the rope onto the drum, which is indicative for remaining layers of the rope on the drum, wherein detection is enabled with at least one switch, sensor or any other element, which can detect the said distance.
The warning device according to claim 1, characterized in that it comprises at least the following elements, namely:
- a pushing cylinder, which ensures proper winding of the rope onto the drum, and the position of which with regards to the drum is indicative for the remaining layers of rope on the drum,

- a switching element and/or preferably a signalling device, which is arranged to emit a sound and/or a visual signal, and

- at least one sensor, switching device or any other element, which can detect the distance between the pushing cylinder and the drum and which can create a signal to the signalling device to warn about the limited amount of rope on the drum.
The warning device according to any of the preceding claims, characterized in that the switch, sensor or any other element, which can detect the distance between the pushing cylinder and the drum, is installed on the housing of the winch or preferably on the pushing cylinder, more preferably on a holder of the pushing cylinder.
The warning device according to any of the preceding claims, characterized in that it preferably comprises an inductive switch, however an optical sensor, an electric switch, a magnetic or a capacitive sensor may be used.
The warning device according to any of the preceding claims, characterized in that the inductive sensor is installed on an accessory and can be set along the height in order to precisely set the distance needed for signalling a limited amount of rope on the drum.
The warning device according to any of the preceding claims from 2 to 5, characterized in that instead of the pushing cylinder any other element for uniform winding of the rope onto the drum is used, for example a sliding plate, preferably made from a softer material such as bronze or plastics so that the rope is not damaged.
The warning device according to any of the preceding claims, characterized in that the pre-set distance for signalling depends on the thickness of the rope installed on the drum and the dimensions of the pushing cylinder and thus connected elements, wherein the usual distance is set to 3 to 8 mm, as this range satisfactorily covers the dimension proportions equivalent to the last layer of the rope wound on the drum.
The warning device according to any of the preceding claims, characterized in that the switch or the sensor is at the same time a switching element arranged to automatically terminate unwinding of the rope or the switch is preferably arranged to transmit a signal to the signalling device, which warns a user to manually terminate unwinding of the rope.
The warning device according to any of the preceding claims, characterized in that the signalling device is installed on the housing of the winch, preferably on higher parts of the housing, so that it is highly visible.
The warning device according to any of the preceding claims, characterized in that the connection between the signalling device and the switch or the sensor is electronic, electric or mechanic, depending on the type of sensor or the switch as well as on the position of the signalling device or the switching element, preferably the connection with the preferred inductive sensor is an electric wire, which sends the signal to the signalling device to warn the user or to the motor, which automatically terminates unwinding of the rope.
The warning device according to any of the preceding claims, characterized in that termination of unwinding of the rope is carried out automatically, wherein unwinding of the rope is automatically terminate due to a mechanic connection using suitably shaped handles or levers, or due to a direct switching of the drum drive, wherein activation of the switch or the sensor causes a change of status of a hydraulic or electric circuit of the drum from on to off.
Operation of the warning device according to any of the preceding claims, characterized in that upon unwinding of a rope from a drum a pushing cylinder approaches the drum, the pushing cylinder reaches the pre-set distance, which is sensed with an inductive sensor and causes an automatic termination of rope unwinding or causes transmission of a signal to a signalling device, so that a user can see it and suitably manually terminate rope unwinding in any known manner.
A forestry winch with the warning device according to any of the preceding claims from 1 to 11.
The forestry winch according to the preceding claim, characterized in that the winch drum is provided with a pushing cylinder installed on forks, which oscillate around their mounting, wherein the tension of the pushing cylinder is enabled with a spring or any other suitable element; that the spring, which pushes the cylinder is a tension, compression, torsion or gas spring, wherein the said spring is arranged to pull the forks and thus push the pushing cylinder on the drum with the rope, thereby ensuring better winding of the rope onto the drum and preventing uncontrolled unwinding of the wire rope; that the pushing cylinder upon winding of a new layer of the rope moves farther away from the drum, while the axis of forks is rotated; that by unwinding the rope from the drum the diameter of the current rope on the drum is decreasing and the pushing cylinder is consequently approaching the drum centre, which can be sensed by the sensor or the switch at a pre-defined distance, consequently leading to automatic termination of unwinding or sending a signal to the signalling device.