Field of the invention

The present invention relates to wood cutting and chopping machines for the processing of logs for the production of firewood.

State of the art

Typically, these wood cutting and chopping machines comprise a bearing structure, a loading and cutting section formed by a horizontal cradle for supporting the logs, and a motorized saw blade displaceable transversely to the cradle between a raised inoperative position and a lowered cutting position, and a chopping section arranged downstream of the cutting section and including a chopping wedge and a pusher device horizontally displaceable between a retracted position and an advanced position with respect to the chopping wedge. The lowering of the saw blade and the activation thereof are operated by first control means, and the advancement of the pusher device is operated by second control means.

Wood cutting and chopping machines of this type, as described for example in the document DE- 102007003945B3, are provided for use in industrial environments for the production of large quantities of firewood, as well as for small handcrafted or even domestic productions: for these uses, semi-automatic machines are commercially available in which the loading and cutting section and the chopping section are completely inaccessible, in practice, during positioning of the logs and the cutting and chopping operations, besides being poorly visible, for reasons of safety for the operator, who is therefore limited to controlling the activation of the cutting and . chopping cycles by simply checking the correct loading of the logs and the unloading of the chopped pieces after cutting. Machines of this type are suitable for the processing of sufficiently straight and regular logs, such as those typically available in Nordic countries, but are inadequate for operating with the irregular and sometimes twisted logs normally available in Alpine countries. Such logs may involve frequent problems of correct positioning, jamming or at least the need for fast intervention when correct repositioning of the logs and stumps is required. This need, however, is difficult to reconcile with the requirement to ensure maximum operator safety against the risk of accidents, particularly regarding the danger of the cutting blade and also the chopping pusher.

Summary of the invention

The object of the present invention is that of resolving the aforesaid problem in an effective, safe and reliable manner.

According to the invention, this object is achieved thanks to a wood cutting and chopping machine of the type defined in the preamble of claim 1, whose primary characteristic lies in the fact that■ at least the loading and cutting section is open outwards and directly accessible by an operator, in that at least said first control means require simultaneous operation using both hands of the operator, and in that disabling means are provided for blocking the operation of the second control means when the first control means are operated, and for blocking the operation of the first control means when the second control means are operated .

Thanks to this solution idea, the access of the operator, at least to the cutting section, for example, to correctly reposition the log on the cradle, involves, following the release of the respective control means, even with one hand, the immediate stop of the machine so as to guarantee total safety for the operator. The disabling means also securely prevent any sequence errors of the cutting and chopping cycle, avoiding any risk of collision between the respective operating components, that is, the cutting blade and the chopping pusher.

In a preferred embodiment of the invention, the first control means comprise a handle or handgrip rotatable about a horizontal axis starting from a normally raised position and whose downward rotation operates the swinging of the cutting blade, preferably formed by a chain saw, from the inoperative raised position to the lowered cutting position, and a first lever whose continuous operation activates the cutting blade. Inhibiting means are provided to render the lever inoperative, even if operated, before the handle is rotated downwards.

The second control means include a second lever that can be selectively configured to be operated with one or both hands of the operator.

According to another advantageous feature of the invention, the cutting section also includes a hydraulically operated swinging arm for blocking the log on the support cradle. This blocking arm is displaceable from an inoperative raised condition to a lowered operative condition and vice versa, by means of the operation of the first lever. Access to the blocking arm by the operator is therefore securely prevented, both during positioning and during cutting of the log for which, as said, both hands must be engaged .

Brief description of the drawings

Further characteristics of the invention will become evident from the detailed description that follows, referring to the accompanying drawings provided purely by way of non-limiting example, in which :

Figure 1 is a schematic perspective view of a wood cutting and chopping machine according to the invention, represented in an inoperative condition,

Figure 2 is an analogous figure to Figure 1, partially exploded, showing a first operative condition of the machine,

Figures 3 and 4 are analogous views to Figure 2 showing additional operating conditions of the machine, Figure 5 shows the detail indicated by the arrow V in Figure 4 on an enlarged scale,

Figures 6, 7 and 8 are partial back perspective views, on an enlarged scale, showing parts of the machine in three different operating conditions,

Figures 9, 10, 11 and 12 are front perspective views showing other parts of the machine in four different operating conditions, and

Figure 13 shows the hydraulic diagram of the machine .

Detailed description of the invention

Referring initially to Figure 1, the wood cutting and chopping machine according to the exemplified embodiment of the invention comprises a support structure 1, provided with two or more wheels 2 for its transportation, as well as adjustable supports 3 in a stationary condition, on which a loading and cutting section is arranged, generically indicated by 4, along with a chopping section, generically indicated by 5.

The loading and cutting section 4 comprises an inclined cradle 6 on which logs to be cut are deposited and made to advance, a motorized cutting blade 7 for the transverse cutting of the logs into portions or stumps of the required length, a swinging arm or gripper 8 for blocking the log during cutting, and a cutting control device, which will be described, which requires the joint and simultaneous operation of both hands of an operator. A protection cover 9 of the cutting blade 7 is articulated to the top of the support structure 1 and can be manually rotated between the raised position shown in Figure 1, corresponding to the inoperative condition of the cutting section 4, and the lowered position shown in Figure 3. Even in this lowered position, the cutting section 4 is clearly visible and accessible from the outside so as to allow an almost total visual control by the operator and any interventions for the correct positioning of the log and cut stumps, in any case, as will be seen, in total safety.

In the case of the illustrated example, the cutting blade 7 is of the guide bar and chain-type, normally used in chainsaws.

The chopping section 5 comprises a vertical chopping wedge 10 arranged at the end of the support structure 1 opposite to the log inlet end, and a motorized pusher 11 linearly movable toward and away from the chopping wedge 10, alongside the cradle 6. Control of the pusher device 11 is operated in the manner explained below.

In the configuration represented in Figure 1, in which the cover 9 is opened and raised, the machine can only be used for the chopping of stumps, in turn positioned between the wedge 10 and the pusher device 11, which is then advanced to push the stump through the wedge 10.

Immediately downstream of the chopping wedge 10, a collection platform 12 of the chopped pieces is arranged, which is removable and can be replaced, if necessary, by a collector or motorized evacuation conveyor .

The wedge 10 is displaceable horizontally, together with the tray 12, by means of a telescopic support (Figure 2) which allows the operation, both for cutting and for chopping, with pieces of wood of variable length, ranging from about 20 cm to 105 cm without constraints.

The cradle 6 has a removable portion 13 to allow the use of the machine exclusively for chopping operations and the access to a movable vertical baffle plate 14 displaceable between a lowered position, illustrated in the drawings, in which stumps cut from the log can, in turn, roll or shift laterally onto the chopping section 5, and a raised position in which the cut stumps are directly unloaded from the machine, without chopping. In this case, the machine can only operate as a log-cutter.

For controlling the cutting section 4, the machine includes a handle 15 articulated to the back of the support structure 1 around a horizontal axis and displaceable with one hand from the raised position shown in Figure 2, to the lowered position illustrated in Figure 3, for controlling the corresponding displacement of the chain 7 from the essentially vertical raised position, represented in Figures 1, 2 and 4, to the lowered cutting position represented in Figure 3, in which it extends transversely above the cradle 6.

Access to the handle 15 is only allowed in the lowered position of the protection cover 9 and its downward rotation is only allowed in the case in which the pusher device 11 is in the retracted position. To this effect, a mechanical disabling system is provided, formed by an swinging stop lever 16, cooperating with an abutment 17 of the handle 15, which is deactivated in the retracted condition of the pusher device 11 and is rotated in the blocking position against the abutment 17 as soon as the pusher device 11 is made to advance, in the manner represented in detail in Figure 5 with a dashed line and a solid line, respectively.

As will be seen, the cutting disabling system, including the blocking arm 8, also includes, in addition to the mechanical system described above, a hydraulic system which will be described: in this way, any errors in the sequence of the cutting and chopping steps, which could pose a risk of collision between the cutting blade 7 and the chopping pusher device 11 are prevented in a totally safe manner.

Referring now in greater detail to Figures 6 to 8, a lever 18 is also provided for controlling the cutting section 4, carried by a support 19 arranged at the back of the cradle.6 and rotatable around a vertical axis to control the activation of the chain 7 through the hydraulic circuit, which will be described hereinafter. For cutting operations, the lever 18 must be pulled with the other hand of the operator, that is, the one that is not operating the handle 15, and its release causes the immediate deactivation of the chain 7. The cutting maneuver operated with the lever 18 also controls the activation of the blocking arm 8, or rather its swinging from a raised inoperative position (shown in detail in Figures 9, 11 and 12) to a lowered position against the log to be cut (shown in Figure 10 and with a dotted line in Figure 11) .

The chain 7 is operated by a hydraulic motor 20 through the hydraulic circuit shown in Figure 13: an electric motor 21 (or a different power source) drives a pump 22, which in turn drives the hydraulic motor 20 through a first spool valve 23 controlled by the lever 18, and a second spool valve 24 indirectly operated by the handle or handgrip 15. This operation is achieved by means of a roller lever 25 cooperating with a bracket 26 in the manner illustrated in Figures 6 to 8 : in the raised position of the handle 15, the roller lever 25 holds the bracket 26 in the raised position against a stop 27, so that it is impossible to operate the motor 20. When the handle 15 is lowered down to a preset point, the roller lever 25 rotates, freeing the bracket 26 and the valve spool 24 moves, freeing the movement of the lever 18 which then, if operated, opens the passage of the hydraulic fluid towards the motor 20, thereby operating the chain 7. The release of the lever 18 causes the immediate stop of the chain 7, by means of the valve 23, and in the same way, the release of the handle 15 causes the displacement of the hydraulic flow of the valve 24 into a discharge condition, generating the stop of the chain 7, in addition to its return to the raised position.

As is evident in the diagram of Figure 13, the valve 24 also controls the blocking arm 8 by means of a linear hydraulic actuator 37, activated by a hydraulic accumulator 38.

Numeral 28 indicates a hydraulic device (not represented in the diagram of Figure 13) inserted into a lubrication circuit 33 of the chain 7 during cutting: this device includes a piston and a tap 29 for the possible closing of the lubrication circuit if required: if the tap 29 is closed, the piston of the device 28 is locked under pressure and retains the bracket 26 in the raised position, even in the case in which the handle 15 is rotated downwards, so as to maintain the valve 24 in a contrasting position to the command of the lever 18, thereby inhibiting the functioning of the hydraulic motor 20, and therefore the chain 7, in the absence of lubrication. Returning to Figure 13, the hydraulic circuit also includes a third spool valve 30 for the operation of a linear hydraulic actuator 32, which controls the forward and retraction displacements of the pusher device 11. The spool valve 30 is controlled by a lever 31, also carried by the support 19, which can be single, as in the case of the example illustrated, or double, which thus requires the simultaneous presence of both hands of the operator for its operation to control the advancement of the pusher device 11.

As is illustrated in detail in Figures 9-12, the chopping cycle operated by the lever 31 is impeded, during the cutting cycle of a log T, by means of a disabling system acting directly on the lever 31. This system includes a mechanical stop formed by a swivel rod 35 connected at one end to the handle 15, for example, by a gas spring 41, and formed at the other end by an abutment 36 facing the base of the lever 31. When the handle 15 is moved with one hand from the raised position towards the lowered position, the rod 35 is rotated so as to position the abutment 36 against the lever 31, the displacement of which corresponding to the advancement of the pusher device 11, is thus blocked (Figure 9) .

When the lever 18 is pulled in a continuous manner to operate the blade 7 (Figure 10), the actuator 37 is activated by the accumulator 38, causing the lowering of the arm 8 against the log T, which is thus locked during cutting.

When cutting has finished, the lever 18 is released so that it returns to the starting position to interrupt the functioning of the blade 7. Then, to bring the arm 8 into the raised position, it is necessary to push the lever 18 in the opposite direction (Figure 11). To proceed to the chopping, the handle 15 must be returned to the raised position, so as to free the lever 31 from the abutment 36 of the rod 35, that can therefore be operated, in this way, to control the advancement of the pusher device 11 (Figure 12) .

Even in the case in which the advancement of the pusher device 11 is controllable by a single lever 31, and therefore by only one hand of the operator, the dual safety created by the elements 35-36 as well as by the hydraulic circuit, however, prevents any possibility of sequence errors of the cutting and chopping steps.

The advancement of the log T for cutting can be carried out manually or by means of a hydraulic pusher, indicated by 39 in the diagram of Figure 13, whose stroke is adjustable.

The chopping section 5 can be completely open and therefore directly accessible by the operator, as in the case of the example illustrated, or may be provided a slidable protection (not shown) , the opening of which can interrupt the functioning of the machine by means of a safety valve indicated by 40 in the diagram of Figure 13.

Finally, the portion 13 with the relative movable vertical baffle plate 14 can be associated with a manually-operated lifting device to facilitate the rolling of the cut log-pieces in front of the chopping wedge 10.

It is evident that the description of the wood cutting and chopping machine according to the invention presents a configuration entirely suitable for cutting and/or chopping of timber that is also irregular, allowing the operator to intervene at his discretion to position or reposition the pieces subjected to cutting and/or to chopping according to requirements, guaranteeing, in any case, the maximum safety against injury risks for the operator.

Of course, the details of construction and the embodiments may be widely varied with respect to what is described and illustrated, without departing from the scope of the present invention as defined in the following claims.