Log sawing machine

Abstract

 Trunk sawing machine comprising a rotary saw disk (3) provided with a moveable cover (8), and a swinging structure (7) for the trunk (T) to be cut displaceable from a receded inoperative position, in which the cover (8) encloses the saw disc (3), towards a cutting advanced position in which the trunk is progressively moved against the saw disc (3) to be severed into successive pieces. The machine also comprises a safety device (20) to inhibit discharge of the residual trunk resulting from cutting the last piece until the swinging structure (7) is brought to the receded position. The displacement of the swinging structure (7) may be provided by a lever (13) operable to positively provide advancement and return thereof both quick and slow to the receded position.

Description

Field of the invention

[0001] The present invention refers to trunk sawing machines with rotary saw disk and swinging structure (or vat) of the trunk to be cut.

Prior art

[0002] Over the years, the Applicant has been manufacturing and selling trunk sawing machines thus made comprising a cover of the saw disc moveable between an advanced condition in which it encloses the saw disc and a receded condition, a feeding carriage of the trunk displaceable along a guide arranged at right angles relative to the saw disc, and a swinging structure for supporting the guide operatively connected to the cover and movable relative to the saw disc from a receded inoperative position, in which the cover is located in the advanced condition, towards a cutting advanced position in which the trunk positioned on the feeding carriage is progressively moved against the saw disc, while the cover is located in the receded condition, to be severed into successive pieces having a length corresponding to the amount of displacement of the carriage along the guide. Further provided for are servo-actuator means to displace the swinging structure between the receded and advanced positions, and manually-operable control means of the servo-actuator means.

[0003] A machine of this type is also known from US-1566191.

[0004] During use, these trunk sawing machines often expose the operator to risks related accidents, most of which occur during the final step of the operation when, lack of attention or so as to accelerate the times of execution, the operator tends to push the residual part of the trunk previously cut into pieces out of the machine, without waiting for the complete return of the swinging structure to the inoperative receded position, i.e. before the saw disc is entirely enclosed in the cover correspondingly moved towards the advanced condition. In such event, statistically the operator is exposed to much higher risks of injuring the hand thereof.

Summary of the invention

[0005] The object of the present invention is that of overcoming the abovementioned drawback, and providing an improvement for trunk sawing machines thus made hence allowing drastically reducing, and even eliminating, the exposure of the operator to risks of accidents in the situations described beforehand.

[0006] According to the primary characteristic of the invention, such object is attained due to the fact that the trunk sawing machine further comprises a safety device to inhibit the discharge of the residual portion of the trunk resulting from cutting the last piece or other residual portions from said carriage until the swinging structure is brought to the receded condition.

[0007] According to a preferred embodiment of the invention, the safety device comprises a tiltable stop member located immediately downstream of the saw disc with respect to the displacement path of the trunk and moveable between an inoperative position, in which it does not obstruct such path, and a stop position in which it instead intercepts such path. The inoperative position of the tiltable stop member corresponds both to the inoperative receded position of the swinging structure, and the step of cutting the trunk by the saw disc, and the displacement of the tiltable stop member to the stop position is borne out, under the action of the return means, at the end of the step for cutting the trunk.

[0008] In practice, the tiltable stop member - for example made up of a shaped bar pivoted around a stationary axis of the machine or around a moveable axis with the cover of the saw disc - automatically disappears from the working zone only when the saw disc is enclosed in the cover, i.e. in the step in which the swinging structure is completely receded, in such a manner to allow the operator to safely remove the residual piece of the trunk already cut, or positioning a new trunk to be cut, or other operations, without exposing the operator to the risk of inadvertently intercepting the saw disc. The tiltable stop member does not cause any hindrance during the cutting step, in that it is held, by the same trunk, outside its displacement path until the cutting operation is completed. In such situation, the tiltable stop member is thus capable of rotating rapidly in the stop position thereof, in such a manner to prevent the operator from performing the operation of discharging the residual piece of trunk before the saw disc is entirely enclosed in the cover thereof.

[0009] This solution offers considerable advantages, in that the safety device according to the invention is extremely simple and inexpensive, practically it does not require maintenance, it does not create any type of hindrance or obstacle during the operating cycle, and it does not require any adjustment. Furthermore, obviously alongside hindering reckless and hazardous actions that could expose the operator to serious accidents, it does not give rise to longer operating cycle times.

[0010] According to another aspect of the invention, the manually-operable control means of the servo-actuator means that provide for the displacement of the swinging structure comprise a single lever positively operated to provide both the displacement of the swinging structure from the receded position to the advanced position and rapid return thereof to the receded position and then stop thereof in such position. In addition, the positioning is such that releasing the positive operation of the lever provides return, conveniently at a low speed, of the swinging structure to the receded position.

[0011] Such characteristic facilitates the cutting and return control of the swinging structure, alongside quickening it in that the operator is not required to check or decide whether the cutting operation has been completed or not before proceeding to reverse the control, but the operator simply operates the same lever in the same manner. Thus, the entire cutting and return cycle, whose speed may be selectively adjusted, occurs naturally and rapidly, but forcing the operator to constantly operate the lever manually. Even this constant operation of the lever, typically performed using the right hand, allows not exposing the operator to risks of accidents.

[0012] The automatic cutting and return step in a single sequence may however be interrupted or reversed at any time, by simply releasing the lever: in such case, the swinging structure shall automatically return to the receded position, but - as mentioned - more slowly with respect to the automatic cycle. This slower return makes the machine safer, in case the cutting step requires to be interrupted due to occurrence of unexpected problems. In such case, the saw disc shall slip off from the cavity of the cut already performed in the trunk in an easy manner and without causing problems related to hazardous jamming or seizure.

[0013] The combination between the safety device to inhibit untimely discharge of the trunk and the single lever control system, which provides both the cutting displacement and the return displacement of the swinging structure, cooperate to ensure extremely safe and even quick working conditions, also accelerating the times required for performing the cycle of cutting and removing the cut pieces. However, the system is safe even without being associated to hydraulic control, but simply using a traditional manual control of the swinging structure.

Brief description of the drawings

[0014] Further characteristics and advantages of the invention shall be clear over the detailed description that follows, with reference to the attached drawings strictly provided for exemplifying and non-limiting purpose, wherein:

• figure 1 is a schematic perspective view of a trunk sawing machine according to the invention, represented in a first condition, with the feeding carriage open at operating position,
• figure 2 is a view analogous to figure 1 showing the trunk sawing machine in a second condition, with the feeding carriage overturned-closed in transport position,
• figures 3-6 are four schematic side elevational views of a part of the machine according to figures 1 and 2, exemplifying the operation of the safety device according to a first embodiment,
• figure 7 shows, in larger scale, a detail of figure 1,
• figures 8, 9 and 10 are views respectively analogous to figures 3, 5 and 6 showing the operation of a second embodiment of the safety device,
• figure 11 is a side elevational view, partial and simplified, of figure 1,
• figure 12 is a front elevational view of figure 11,
• figure 13 is a side elevational view, partial and simplified, of figure 2, and
• figure 14 is a front elevational view of figure 13, and
• figure 15 illustrates the hydraulic control diagram of the swinging structure of the machine.

Detailed description of the invention

[0015] Figures 1 and 2 schematically illustrate a trunk sawing machine according to the invention in two different operating conditions outlined hereinafter. The machine is of the generally conventional type and thus only the essential components thereof as well as those expressly referring to the invention shall be described.

[0016] The trunk sawing machine comprises a framework 1 having wheels 2 rotating at whose upper part, around a horizontal axis, is a saw disc 3 rotated by a motorised unit 4.

[0017] Indicated with 5 is an overturnable horizontal guide arranged transverse with respect to the saw disc 3 and moveable along which is a feeding carriage 6 of the trunk to be cut, indicated with T in figures 3 to 5 and 8 to 10. The guide 5 is borne by a swinging structure generally indicated with 7, which is pivoted to the framework 1 around an axis 35 and is movable relative to the saw disc 3, together with the guide 5, between the completely receded inoperative position illustrated in figure 1, and the completely advanced position illustrated in figure 2, to move the trunk T fed through the carriage 6 progressively against the saw disc 3, thus executing the cutting in successive pieces having a length corresponding to the amount of displacement of the carriage 6 along the guide 5. Such displacement is usually performed by pushing manually.

[0018] The swinging structure 7 also bears a cover 8 of the saw disc 3, provided with a slit 9 suitable to be passed through by such saw disc 3 when the swinging structure 7 is moved from the receded position towards the advanced position. In the receded position, the saw disc 3 is completely enclosed in the cover 8, while during the displacement of the swinging structure 7 towards the advanced position, such cover 8 is progressively positioned at a receded position in which the saw disc 3 is exposed for progressively cutting the trunk T.

[0019] The displacement of the swinging structure 7 is performed by means of a double effect hydraulic jack 10 whose drive circuit is schematized in figure 15. A hydraulic pump 11 provides pressurised oil to one or the other chamber of the jack 10 through the a four-position distributor valve 12 (or even possibly just a three- position distributor valve) actuated by a tiltable control level 13 borne, at an easily manoeuvrable position, by the swinging structure 7.

[0020] The cutting speed, i.e. the contraction of the hydraulic jack 10 to move the swinging structure 7 from the receded position to the advanced position is adjustable by means of a control knob 36 inserted into the hydraulic control circuit of the jack 10.

[0021] Indicated with 14 is a pipe slidingly borne by the swinging structure 7 and inserted in which is a bar 19. The pipe 14 and the bar 19 define a double sliding system associated to which is a telescopic strut 16 and a flexible tie 17, outlined further hereinafter expressly referring to figures 11 to 14. As observable hereinafter, such double sliding system 14, 19 actuates a moveable stop member 15 operatively associated to the control lever 13.

[0022] The machine operates in a generally conventional manner: the trunks T to be cut are positioned one by one on the carriage 6, which is moved until the end of the trunk is positioned against a stop member indicated with 18 in figures 1 and 2. Thus, the cutting cycle is actuated by operating the lever 13, through the methods further specified in detail hereinafter, in such a manner to displace the swinging structure 7, through the hydraulic jack 10, from the receded position of figure 1 in which the cover 8 completely encloses the saw disc 3 as represented in figure 1, towards the completely advanced position represented in figure 2. Due to such displacement, the cover 8 progressively uncovers the saw disc 3 through the slit 9, while the trunk T arranged on the carriage 6 is cut producing a piece which is thus discharged from the machine. By continuously actuating the control lever 13, the swinging structure 7 is thus returned to the initial receded position to allow the cutting of a further piece of the trunk T.

[0023] After cutting successive pieces, usually of the same length defined by the position of stop element 18, left on the carriage 6 shall be a residual piece to be discharged from the machine. Such operation is usually performed by the operator by pushing the residual piece manually: thus, in conventional machines there arises the serious risk that this operation be performed before the swinging structure 7 has entirely returned to the receded position, i.e. before the saw disc 3 is entirely enclosed within the cover 8, leading to the ensuing risks.

[0024] In order to overcome this drawback, the invention provides for - according to a first aspect - a safety device having the function of preventing the discharge of the residual trunk T resulting from the last piece or other residual pieces from the carriage 6 until the swinging structure 7 completely returns to the receded position.

[0025] In a first embodiment, such safety device is indicated with 20 in figures 3 to 6: it consists in a simple shaped bar borne by a tiltable lever 21 which, as illustrated more in detail in figure 7 is pivoted to a pin 23 rotatingly supported by the structure 22 fixed to the framework of the machine 1 bearing, on the side opposite to the lever 21, an arm 23 countered by a fixed stop member 24 and serving as a reaction element for a torsion spring 25 which is wound on the pin 23 and serves as an elastic element for pushing the safety bar 20.

[0026] Still referring to figures 3 to 6, the safety device represented by the bar 20 operates as follows.

[0027] At the receded position of the swinging structure 7, corresponding to the advanced condition of the cover 8 with the saw disc 3 enclosed therein as mentioned, the bar 20 is kept - due to the abutment of the free end thereof against the swinging structure 7 - at the position represented in figure 3, in which it does not obstruct the displacement path of the trunk T, hence allowing translation thereof along the guide 5 until the cutting position is reached. Hence, by controlling - through manual actuation of the lever 13 - the displacement of the swinging structure 7 from the receded position to the advanced position, the trunk T is moved against the saw disc 3 progressively uncovered by the cover 8, hence causing the further rotation of the bar 20, against the action of the spring 25, as represented in figure 4.

[0028] At the end of the cutting operation, and thus after discharging the piece of the trunk T which is freed from the bar 20, the spring 25 returns such bar 20 to abut against the swinging structure 7, as illustrated in figure 5. The bar 20 is brought to obstruct the displacement path of the residual trunk T positioned on the carriage 6, thus hindering any displacement attempt towards the stop member 18 until the swinging structure 7 is returned to the completely receded position corresponding to which - as mentioned - is the advanced condition of the cover 8, in which the saw disc 3 is completely enclosed therein (figure 3).

[0029] The same effect may be obtained by means of the variant of the safety device represented in figures 8 to 10, which also engages a simple shaped bar 26 which is however pivoted to the cover 8 around an axis 27. In this case, the return operation of the bar 26 towards the obstruction position is obtained by means of a counterweight 28 connected to a tie 29 having a compensation spring 30 associated thereto.

[0030] Now, referring to figures 11 to 14 following is a description of the details according to which the control lever 13 operates for the actuation of the hydraulic jack 10 which controls the displacement of the swinging structure 7.

[0031] As mentioned previously, the swinging structure 7 bears the sliding pipe 14 moveable within which is the bar 19, defining the double sliding system. At the upper part, the bar 19 positively rotates the stop member 15 between the positions illustrated respectively with a continuous line and with a dashed line in figure 11. At the lower part, pivoted to the bar 19 in 32 is an end of a telescopic strut 16, whose opposite end is pivoted in 31 to the framework 1 of the machine. A spring 30 associated to the lower end of the bar 19 tends to return such bar 19 downwards.

[0032] Adjustably anchored in 33 near the joint 31 is an end of the flexible tie 17 whose opposite end is anchored in 34 to the pipe 14. The pipe 14 is joined, through a second flexible cable - not illustrated - to the control lever 13.

[0033] As mentioned previously, the positioning is such to attain the return of the swinging structure 7 from the advanced position to the receded position at two different speeds: rapid return and slow return. By actuating the control lever 13 to control the displacement of the tiltable structure 7 from the receded position to the advanced position and then continuing to actuate such lever 13 after the cutting of the trunk T, there occurs the rapid return to the receded position of the tiltable structure 7 without interruption. After returning, i.e. when the saw disc 3 is completely enclosed in the cover 8, the operator shall release the control lever 13 and reposition the trunk to be cut against the stop member 18 and repeat the cutting and return operation.

[0034] The automatic cutting and return operation in a single sequence may however be interrupted and reversed at any time, by simply releasing the control lever 13: in this case, the swinging structure 7 shall return towards la receded position in a slower manner.

[0035] In detail, the control lever 13 is suitable to acquire - starting from a neutral position indicated with "0" in figure 12 - three different control angular positions, respectively indicated with "1" still in figure 12 and with "2" and "3" in figure 14.

[0036] Assuming starting from the completely receded position of the swinging structure 7 represented in figure 11: the operator, by moving the control lever 13 from position "0" to position "2", controls the contraction of the jack 10 and thus the displacement of the swinging structure 7 towards the advanced position of figure 13, performing the cutting of the trunk T. Upon performing the cutting operation, the operator has two options for the return step: by holding the control lever at position "2" the swinging structure 7 is held in the advanced position, while by releasing such lever 13 the swinging structure 7 slowly returns towards the receded position. In such case, the downwards sliding of the pipe 14 along the bar 19 automatically returns the control lever 13 to position "0", stopping the swinging structure 7 at the receded position.

[0037] On the contrary, should the control lever 13 be actuated with greater force during the final step of the displacement of the structure towards the advanced position, it may be positioned at position "3", due to the upwards axial movement with respect to the stop member 15 from the position indicated with "A" to the position indicated with "C" in figure 11, operated by the bar 19 pushed upwards by the strut 16 after the displacement of the swinging structure 7 to the advanced position. By holding the control lever 13 at position "3", the extension of the jack 10 rapidly returns the swinging structure 7 to the receded position. Hence, upon reaching such position, releasing the control lever 13 automatically determines the displacement thereof to position "0".

[0038] Position "0" of the control lever 13 is attained at this step also due to the rotation of the stop member 15 from position "A" to position "C", facilitated by the axial downwards sliding downwards with respect to the bar 19 under the action of the spring 30.

[0039] The upwards rotation of the stop member 15 from position "A" to position "C" is - as mentioned - performed by the axial upwards displacement of the bar 19, in turn moved by the telescopic strut 16 pivoted in 31 to the structure 1 of the machine and in 32 to the bar 19: the approaching between the rotation axes 31 and 32, after the displacement of the swinging structure 7 from the receded position of figure 11 to the advanced position of figure 13, thus allows obtaining the passage of the control lever 13 from position "2" to position "3". Generated in the subsequent step of returning the swinging structure 7 towards the receded position of figure 11 is a reverse away movement between 31 and 32, and the downwards return of the bar 19 operated by the spring 30. This sequence, associated to the rotation of the stop member 15, allows the passage of the control lever 13 from position "2" - "3" to position "0". In the final step of such displacement the flexible cable 17 - adjustably anchored, as mentioned, in 33 to the frame work 1 and in 34 to the pipe 14, controls the sliding of such pipe 14 - with respect to the bar 19 and the ensuing displacement - by means of a further tie (not illustrated), of the control lever 13 at position "0" - to complete the step of returning the swinging structure from the receded position as well as the entire operating cycle.

[0040] It should be observed that, regardless of the point where the control lever 13 is released by the operator during the step of cutting the trunk, the swinging structure 7 shall always return to the completely receded position with the saw blade 3 completely enclosed inside the cover 8.

[0041] Obviously, the construction details and embodiments may widely vary with respect to what has been described and illustrated without departing from the scope of protection of the present invention, as defined in the attached claims.

[0042] Same case applying to the sole application of the device suitable to hinder reckless discharge of the last piece on pre-existing machines, or on machines manufactured without the automatic cutting control, i.e. the traditional type.

Claims

1. Trunk sawing machine comprising a rotary saw disk (3), a cover (8) of the saw disc (3) moveable between an advanced condition in which it encloses the saw disc (3) and a receded condition, a feeding carriage (6) of a trunk (T) displaceable along a guide (5) arranged at right angles relative to the saw disc (3), a swinging support structure (7) of said guide (5) operatively connected to said cover (8) and movable relative to the saw disc (3) from a receded inoperative position, in which said cover is located in said advanced condition, towards a cutting advanced position in which the trunk (T) positioned on said feeding carriage (6) is progressively moved against said saw disc (3), while said cover (8) is brought to said receded condition, to be severed into successive pieces having a length corresponding to the amount of displacement of said carriage (6) along said guide (5), servo-actuator means (10) to perform displacement of said swinging structure (7) between said receded and advanced positions, and manually-operable control means (13) of said servo-actuator means (10), characterised in that it further comprises a safety device (20; 26) to inhibit discharge of the residual portion of trunk (T), resulting from cutting the last piece or other residual portions, from said carriage (6)until said swinging structure (7) is brought to said receded position.

2. Trunk sawing machine according to claim 1, characterised in that said safety device comprises a tiltable stop member (20; 26) located immediately downstream of said saw disc (3) with respect to the displacement path of the trunk (T) along said guide (5) and moveable between an inoperative position, in which it does not obstruct said path, and a stop position in which it intercepts said path; said inoperative position of the tiltable stop member (20; 26) corresponding both to the inoperative receded position of said swinging structure (7) and to the step of the trunk (T) being cut by said saw disc (3), and displacement of said tiltable stop member (20; 26) towards said stop position being operated by the action of the return means (25; 28) at the end of the step for cutting the trunk (T).

3. Trunk sawing machine according to claim 2, characterised in that said return means are resilient means (25) or counterweight means (28).

4. Trunk sawing machine according to claim 2, characterised in that said tiltable stop member (20) is pivoted around a stationary axis (22).

5. Trunk sawing machine according to claim 2, characterised in that said tiltable stop member (26) is pivoted around a moveable axis (27) borne by said cover (8).

6. Trunk sawing machine according to claim 2, characterised in that said tiltable stop member is a shaped bar (20; 26).

7. Trunk sawing machine according to one or more of the preceding claims, characterised in that said manually-operable control means of said servo-actuator means (10) comprise a single lever (13) a positively operated to provide both the displacement of the swinging structure (7) from said receded position to said advanced position, and rapid return thereof to said receded position and then stop thereof in said receded position.

8. Trunk sawing machine according to claim 7, characterised in that releasing the positive operation of the lever (13) provides return of said swinging structure (7) to said receded position, at a lower speed.

9. Trunk sawing machine according to claim 7 or 8, characterised in that to said lever (13) a movable stop member (15) is operatively associated which can be displaced by a dual-slide rod (14, 19) borne by said swinging structure (7) and designed, upon displacement thereof from the receded position to the advanced position, to enable said control lever (13) to provide return of said swinging structure (7) from the advanced position to the receded position at a higher speed.

10. Trunk sawing machine according to claim 9, characterised in that a telescopic strut (16) and a flexible tie (17) are provided for operating said dual-slide rod (14, 19).

Drawing