The invention relates to the field of tool holders and quick coupling units in particular tool holders for machines, such as excavators, foresting machines, building machines, cranes and so on. The invention relates in particular to an improved safety mechanism that substantially reduces the risk of accidents related to such tool holders and quick coupling units.
Tool holders are widely used in order to connect various tools such as shovels, hammers, vibrators, claw arms, cutters and so on to excavators, forestry machines or robotic machines. The tool holders are thereby adapted to fit onto standardized tool adapters typically comprising a pair of bracket pins, the tool adapters being rigidly connected to the tool. The tool holders typically comprise a hook shaped cut out, which can engage one of the bracket pins and a cut out interacting with a locking element that is connected to an actuator, whereby the other of the bracket pins can be arranged in said cut out and locked by extending the locking element via the actuator. This connection has proven to be useful and variations of it are widely used in the construction industry, the foresting industry and many other heavy industries. Problems that can arise relate to the issue that one of the two bracket pins is typically hidden from the operators view and that the hook shaped cut out does not lock the bracket pin but just engages the bracket pin like a hook does with an opening through which the bracket pin theoretically can still escape in case a machine arm is tilted or due to excessive oscillation of the tool on the tool holder.
Typically, the process of coupling a tool to a tool holder comprises the following locking sequence or steps:
A typical unlocking sequence or release of the tool from the tool holder typically comprises the following steps:
A problem that arises with this locking sequence is that during steps a), b), d), e) and partially f) the tool is not 100% secured to the tool holder, which can lead to accidents with falling tools in particular if the operator tilts the machine arm in the wrong way, if the machine is moving or if the tool is oscillating. Accidents with unsecured or falling tools have to be prevented at all cost as they can lead to injuries or fatalities and/or material damage.
The WO 2004067855 A1 discloses a tool holder where the above described coupling—and decoupling sequences are used.
Another problem that may arise is that the operator falsely assumes that the rear bracket pin is properly locked when it is not for example due to jamming or false positioning of the rear bracket pin, which may also lead to dangerous situations and potential accidents as the operator will start to operate the machine as if the tool was properly locked, which can also lead to a falling tool that causes potential hazard.
In light of the above risks and problems a new locking mechanism for a tool holder, which allows to make the above-mentioned locking and unlocking sequences a) to f) safer is herewith disclosed.
An object of the present invention is to provide a tool holder that is safe, reliable and robust.
The inventor of the present invention has realized that it is possible to design a locking mechanism that prevents that any of the cut outs or hook shaped recesses in the tool holder from being open so that a front- or rear bracket pin of a tool can disengage without being hindered in a form-fit manner. In particular the inventor realized that an actuator, which is typically used to lock a rear bracket pin of the tool in a cut-out (WO 2004/067855 A1), can be used to also securely lock the front bracket pin in the hook shaped recess in a form-fit manner and that this in particular can be done sequentially. The solution presented by the inventor locks one of the bracket pins of the tool at any time the tool is coupled or partially coupled to the tool holder.
Disclosed herein is a tool holder for a machine comprising a frame and an actuator that can be moved from a retracted state to an extended state and back. The frame comprises a hook shaped recess having an opening and a cut out arranged at a distance from the hook shaped recess so that a front bracket pin of a tool can releasably connect to the hook shaped recess by entering via the opening and a rear bracket pin of the tool can releasably connect to the cut out. The actuator is fixedly connected to the frame with one end, the actuator further comprises a locking element that is designed to change the shape of the cut out in the extended state of the actuator. The actuator further comprises a securing assembly designed to reduce the size of the opening of the hook shaped recess in the retracted state of the actuator, whereby the rear bracket pin can enter the cut out in the retracted state of the actuator and wherein the front bracket pin can enter the hook shaped recess in the extended state of the actuator.
As explained above, typically, the process of coupling a tool to a tool holder comprises the following locking sequence or steps:
A typical unlocking sequence or release of the tool from the tool holder comprises the following steps:
The above-described and herein disclosed tool holder increases the safety during the steps i), ii), v), vi) and partially vii) for the following reasons:
Before performing step i) the actuator has to be extended so that the opening of the hook shaped recess is equal to or greater than the diameter of the front- and rear bracket pin of the tool, which means that the front bracket pin can engage in the hook shaped recess. During this extended state of the actuator the locking element is blocking the rear bracket pin from entering the cut out, which means that prior entering step ii) the actuator needs to be retracted, thereby inevitably securing the front bracket pin in the hook shaped recess by changing the size of the opening to smaller than the diameter of the front bracket pin via the securing assembly. Now step ii) can be performed once the rear bracket pin is snug engaged in the cut out and the locking element may secure the rear bracket pin in the cut out and the front bracket pin in the hook shaped recess.
The presented solution will therewith increase the safety during steps i), ii) but in particular during step i).
It may for instance further be possible to prevent the machine arm or the entire machine from lifting during step i) and only allow a machine arm operation once step i) is completed, thus once the actuator is retracted and the front bracket pin is secured in the hook shaped recess by the securing assembly.
The tool holder according to the invention also improves the safety of the tool manipulation in particular during decoupling of the tool from the tool holder and therewith in particular during the above presented steps v), vi) and vii). The tool is safely secured in the tool holder during the entire decoupling sequence from iv) to vii) until the actuator is moved from the retracted state to the extended state thereby enlarging the opening of the hook shaped recess via the securing assembly so that the front bracket pin can disengage from the hook shaped recess.
The tool holder disclosed herein therewith increases safety substantially.
It is to be noted that the retracted position or state of and the extended position or state of the actuator may be interchanged. Likewise, may the position of the rear bracket pin and the front bracket pin and therewith the hook shaped recess and the cut out be interchanged.
In an embodiment disclosed herein the locking element is designed to change the shape of the cut out from a cut out to a hook shaped cut out as seen in a cross-sectional plane being cut through the tool holder and the cut out, said cross sectional plane being oriented perpendicular to a longitudinal axis of the rear bracket pin of the tool, when said rear bracket pin is snug embedded in the cut out.
The change of the shape of the cut out to a hook shaped cut out leads to a form fit connection between the hook shaped recess and the now hook shaped cut out.
In an embodiment the hook shaped recess and the hook shaped cut out may have openings that are facing one another or facing away from one another.
This way a form fit connection may be achieved.
In a further embodiment the opening is equal or greater than a diameter of the rear- or front bracket pin of the tool, when the actuator is in the extended state, and wherein the opening is smaller than a diameter of the rear- or front bracket pin of the tool, when the actuator is in the retracted state.
This may lead to the above locking effects once the actuator is retracted or extended using the securing assembly to change to the size of the opening.
In another embodiment the size of the opening is measured in a cross-sectional plane cut through the tool holder and the hook shaped recess, said cross sectional plane being oriented perpendicular to a longitudinal axis of the front bracket pin of a tool, when said front bracket pin is snug embedded in the hook shaped recess.
The above may mean that the securing assembly and the hook shaped recess are not arranged in the same plane or cross-sectional plane, however the invention still works independent of the depth position of the securing assembly and the hook shaped recess as seen in any cross-sectional plane.
In a further embodiment the actuator may comprise a rod and a housing into which the rod can retract and from which the rod can extend, wherein the rod is connected to the frame and wherein the housing is moving in relation to the frame when the actuator is moving between the retracted and the extended state and wherein the securing assembly and the locking element are fixedly connected to the housing.
The rod and the housing may be part of a pneumatic or hydraulic cylinder solution, a cork-screw solution or any other suitable solution such as an electric motor arrangement using induction or magnetism.
In an embodiment the securing assembly and the locking element extend in opposite directions from the housing and said opposite directions may be parallel to a movement path defined by the actuator.
This may lead to an efficient and straight forward design of the tool holder.
In a further embodiment the frame may comprise at least two side plates and a web, the web interconnecting the at least two side plates, said side plates being arranged parallel to one another and wherein each of the at least two side plates comprise the cut out and the hook shaped recess.
The above design may lead to a stable embedding of the front- and rear bracket pin in the tool holder.
The actuator may be connected to the web and the frame may further comprise a motion link in which a part of the housing is engaged for controlling the movement of the housing when the actuator is extending and retracting.
In an embodiment the housing of the actuator may be H-shaped, wherein each leg of the H-shape comprises one hydraulic or pneumatic cylinder.
The tool holder may be a tool adapter, a tilt rotator, a rotator, a tiling device or a quick coupling unit.
Disclosed herein is also a method that prevents the machine from moving as long as an unsafe state is present during coupling and/or decoupling of the tool. The method may include to only allow the tool holder to move, in particular during above described steps i), v) and vi) and when it is sensed that the front bracket pin is engaged in the hook shaped recess and the actuator is in the retracted state or position. The method may allow to move the machine when it is detected that the front bracket pin is disengaging during step vii) and when it sensed that the rear bracket pin is not engaged and not secured in the cut out.
The present invention will now be described, for exemplary purposes, in more detail by way of an embodiment(s) and with reference to the enclosed drawings, in which:
Turning now to the figures two embodiments are herewith described in more detail using reference numbers and figures. The invention may be applicable in many ways, which means the two embodiments are in no way limiting to the invention. A first embodiment is shown and explained referring to
The frame 4 further comprises a hook shaped recess 14 and a cut out 16 arranged at a distance from one another on opposite corners of the frame 4 as shown in
From
The basic principle of the invention has now been described referring to a first embodiment shown in
The hook shaped recess 14′ also comprises a lower receiver part 26′ that makes it impossible to disengage the tool 100 from the tool holder 1′.
The method steps described in connection with
The invention has now been described according to the
Even if the rear bracket pin 104 is jammed by the locking element 20, 20′ during coupling, the tool 100 is still secured in the tool holder 1, 1′ by the securing assembly 22, 22′ as explained, since the actuator 2, 2′ is still in the retracted position when the locking element 20, 20′ is jammed and therewith the opening 24, 24′, 240, 240′ is still limited so that the front bracket pin 102 cannot break free or disengage from the hook shaped recess 14, 14′.
Referring to
The securing assembly 22 according to both embodiments may comprise a pair of securing fingers 22 for instance extending from each leg of a H-cylinder housing. In addition, the second embodiment may comprise a pair of latches 22a. The locking element 20, 20′ may also be designed as a pair of locking elements in both embodiments. The pair of securing fingers 22, 22b and/or latches 22a and the pair of locking fingers 20, 20′ may be arranged close to or at the two sides 10, 10′ of the frame 4, 4′. The invention however also works without providing a pair of securing fingers, latches or locking elements but with at least one of each.
Number | Date | Country | Kind |
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23151024.9 | Jan 2023 | EP | regional |