Todorov, Georgi Dimitrov (Via "Complesso" Drugba 2, Sofia, BG)
Mantovani, Alberto (Via per Modena Ovest 44, Massa Finalese, I-41035, IT)
Todorov, Georgi Dimitrov (Via "Complesso" Drugba 2, Sofia, BG)
| 1. | 1). A device for attaching work tools, which device is rotatably constrainable, about two parallel axes (21, 22) to an end of a mobile arm (20), the device comprising at least a first attachment element (2) and at least a second attachment element (3) which are constrainable to respective attachment counterelements (18, 19) solidly constrained to a work tool, the at least a first attachment element (2) being mobile in relation to the at least a second attachment element (3) between a hookedup position at which the at least a first attachment element (2) and the at least a second attachment element (3) are engaged to the counterelements (18, 19) and the work tool is constrained to the mobile arm (20), and an unhooked position, at which the at least a first attachment element (2) and the at least a second attachment element (3) are not engaged to the counterelements (18, 19) and the work tool is unhooked from the mobile arm (20), wherein the at least a first attachment element (2) is mobile by means of a cam mechanism (4). 2). The device of claim 1, wherein the cam mechanism (4) comprises at least a plate (5), rotatable about an activation axis (6), on which the at least a first attachment element (2) is mounted eccentrically with respect to the activation axis (6). 3). The device of claim 2, wherein the activation axis (6) is also a rotation axis (21) of the device. 4). The device of claim 2, wherein the activation axis (6) is different from the two parallel axes (21, 22). 5). The device of any one of the preceding claims, wherein the at least a first attachment element (2) and at least a second attachment element (3) are constituted by a first cylindrical shaft and at least a second cylindrical shaft. 6). The device of claim 5, wherein the at least a second attachment element (3) is coaxial to an axis (22) of the two parallel axes (21, 22) of the attachment device. 7). The device of claim 5, wherein the at least a second attachment element (3) is not coaxial to the two parallel axes (21, 22) of the attachment device. 8). The device of any one of the preceding claims, wherein the cam mechanism is provided with a blocking mechanism which prevents free rotation thereof in a direction which will bring the at least a first attachment element (2) and at least a second attachment element (3) into an unhooked position. 9). The device of claim 8, wherein the blocking mechanism comprises a ratchet mechanism including a cogging (J), arranged peripherally about the plate (5), and a shaped lever (8) which is mobile between a position in which it engages a free end thereof in the cogging (7) for preventing free rotation of the plate (5) in the direction leading to an unhooked position of the at least a first attachment element (2) and at least a second attachment element (3), and a position in which the shaped lever (8) does not interact with the cogging (7). 10). The device of claim 8, further comprising a shaped key (9) which is predisposed to insert in a seating (10), comprising a first portion, afforded on the at least a first attachment element (2), and a second portion, afforded on a counterelement of the counterelements (18, 19), which first portion and second portion face one another in the hookedup position of the attachment elements. 11). The device of claim 10, wherein the shaped key (9) is provided with a security element (11) which is mobile between a position in which the shaped key (9) can be extracted from the seating (10) and a position in which the shaped key (9) engages with the counterelement of the counterelements (18, 19), and the shaped key (9) cannot be extracted from the seating (10). 12). The device of claim 11, wherein the seating (10) is arranged on a plane which contains longitudinal axes of the at least a first attachment element (2) and the at least a second attachment element (3). 13). The device of any one of the preceding claims, wherein the cam mechanism (4) is manually activatable by means of a shaped key. 14). The device of any one of the preceding claims, wherein the cam mechanism (4) is activatable by means of a motorised actuator. 15). The device of any one of the preceding claims, wherein the device comprises a support element (10) provided with two parallel wings (11) which at an end thereof support the at least a second attachment element (3), and at another end thereof support two plates (5) which in turn support the at least a first attachment element (2). 16). The device of claim 12, wherein ends of the at least a first attachment element (2) and at least a second attachment element (3) project externally of the wings (11) and are predisposed to engage in the counterelements (18, 19). |
Technical Field
The invention relates to a device for attaching work tools, such as for example buckets, blades for earth movement and tools for demolition applications. In particular the invention relates to attachable device which are predisposed to be connected to a free end of a mobile arm supported, for example, by a vehicle. Background Art
The prior art describes devices comprising a support element on which attachment devices are mounted, which devices can be engaged to respective counter-elements solidly constrained to the work tool. Typically these attachment devices are constituted by pivots or cylindrical shafts, while the counter-elements are constituted by appendices provided with semi-circular or C-shaped seatings. At least one attachment element is mobile relatively to the others, between a hooked-up position, in which the attachment elements are engaged to the counter-elements of the work tool and the tool is constrained to the mobile arm, and an unhooked position, in which the attachment elements are not engaged to the counter-elements and the work tool is free of the mobile arm.
In general, in the hooked-up position the attachment elements are at least partially housed internally of the semi-circular seatings and are constrained to the seatings. The support element of the attachment device is rotatingly
constrainable about two parallel rotation axes, to the free end of the mobile arm.
The movement the attachment pivots are generally provided with develops from a position of maximum distance and a position of minimum distance between the pivots. According to the conformation of the counter-elements, one of these positions constitutes the hooked-up position of the work tool, and the other is the unhooked position.
Prior art devices exhibit complex mechanisms for movement of the attachment elements or pivots. These mechanisms often comprise hydraulic cylinders associated to oscillating members on which the attachment elements are mounted, or other mechanical chains that include relative motion of a high number of mechanical parts. Known-type devices are overall rather complex in terms of both construction and use, and are also relatively expensive.
The main aim of the present invention is to provide an attachment device for work tools that obviates the drawbacks in prior art devices.
Disclosure of Invention
Further characteristics and advantages of the invention will better emerge from the detailed description that follows, made with reference to the appended figures of the drawings, provided by way of non-limiting example, in which:
Figure 1 is a perspective view of a first embodiment of the attachment device;
Figure 2 is a front view of the attachment device of figure 1, with an enlarged detail thereof;
Figures 3, 4, 5 are three stages of the hooking-up of the device to a mobile arm;
Figures 6 and 7 are a second and a third embodiment of the attachment device:
Figure 8 is a side view of the device of figure 1; Figure 9 is a view according to line S-S of figure 8.
With reference to the figures of the drawings, the attachment device of the present invention is rotatingly constrainable, about two parallel rotation axes 21, 22, to an end of a mobile arm 20. The end of the mobile arm 20 generally comprises a fixed part, or an arm 25, and a mobile part, or con rod 26, which is mobile with respect to the arm 25. The con rod 26 is moved by the stem of a double-acting hydraulic piston which can be commanded to extend and retract and is constrained to the attachment device about a first rotation axis 21. The movement of the con rod 26 induces a rotation of the attachment device about a constraint fulcrum to the arm 25, i.e. about a second rotation axis 22.
The device comprises at least two attachment elements 2, 3 engageable to respective attachment counter-elements 18, 19 which are solidly constrained to a work tool 30, for example a bucket. The attachment elements 2, 3 are preferably constituted by a first and a second cylindrical shaft. In the illustrated preferred embodiment, each attachment counter-element is defined by a pair of C-shaped elements, aligned to one another. Each of the C-shaped elements is positioned with a concavity thereof facing a concavity of the other C-shaped element.
At least a first attachment element 2 is mobile in relation to the other attachment element 3 between a hooked-up position, at which the attachment elements 2, 3 are engaged to the attachment counter-elements 18, 19, and the work tool is constrained to the mobile arm 20, and an unhooked position, at which the attachment elements 2, 3 are not engaged to the attachment counter-elements 18, 19 and the work tool is unattached to the mobile arm 20. In the illustrated embodiment the relative movement between the attachment
elements 2, 3 develops between positions of maximum and minimum distance between the two. In the position of minimum distance (figures 3 and 4), which in this case corresponds to the unhooked position, the maximum distance between the attachment elements 2, 3 is less than the minimum distance that separates the ends of the attachment counter-elements 18, 19. In the position of maximum distance (figure 5), which in the illustrated embodiment corresponds to the hooked-up position, the maximum distance between the attachment elements 2, 3 is greater than the minimum distance which separates the ends of the attachment counter elements 18, 19. The device could however be perfectly adapted to a use in which the attachment counter-elements are shaped symmetrically with respect to the illustrated embodiment, or in which the C-shaped elements have concavities thereof facing outwards. In this case the hooking-up position is the position of minimum distance, and the unhooking position is the position of maximum distance between the attachment elements 2, 3.
The first attachment element 2 is mobile by means of a cam mechanism 4. This cam mechanism comprises at least a plate 5, rotatable about an activation axis 6, on which the first attachment element 2 is mounted eccentrically with respect to the activation axis 6. In the preferred embodiment the first attachment element 2, which is a shaft, is supported by two plates 5 which in turn are rotatably associated to a support element 10, which is provided with two parallel wings 11 which at an end thereof support the second attachment element 3, which is a cylindrical shaft, and at another end thereof support the two plates 5. The ends of the first and the second attachment elements 2, 3, project outwardly of a the wings 11 in order to engage with the attachment counter-elements 18, 19. The rotation of the plates 5 about the activation axis 6 causes a displacement of the first
cylindrical shaft 2 between the hooked-up position and the unhooked position, as can be seen in figures 3 and 5.
In the preferred embodiments illustrated in figures 1 to 6, the activation axis 6 of the plates 5 coincides with a rotation axis 21 of the attachment device, while in the embodiment of figure 7 the activation axis 6 is different with respect to the rotation axes 21, 22 of the attachment device. In the preferred embodiment of figures from 1 to 5, the second attachment element 3 is coaxial to a rotation axis 22 of the attachment device, while in figures 6 and 7 the second attachment element 3 is not coaxial to the rotation axes 21, 22 of the attachment device.
The preferred embodiment of figures 1, 2, 3, 4, 5, where the rotation axis 6 of the plates 5 coincides with a rotation axis 21 of the attachment device and the second attachment element 3 is coaxial to a rotation axis 22 of the attachment device 3, enables the geometric parameters of the work tool or bucket to be respected, in particular the blade movement radius (RL), the interaxis (A) between the centres of rotation and the blade movement angle α. These geometric parameters, indicated in figure 5, are respectively equivalent to the distance between the point of the blade of the tool and the centre of rotation of the tool with respect to the mobile arm 25 (rotation axis 22), the interaxis between the centres of rotation with respect to the arm 25 and the con rod 26, and the angle defined between the blade movement angle (RL) and the interaxis A. A tool's geometric parameters are always supplied by the manufacturer, and an attachment device that enables these parameters to be fully respected is a guarantee of full operational exploitation of the tool. In the embodiments of figures 6 and 7, the device comprises a further rigid connection member (denoted respectively by numbers 31 and 32), with which
the support element 10 in the first case is connected to the arm 25, and in the second case is connected to the arm 25 and to the con rod 26. The cam mechanism 4 is preferably provided with a blocking mechanism which prevents free rotation in a direction which brings the attachment elements 2, 3 into the unhooked position. Preferably the blocking mechanism comprises a ratchet gear comprising a cogging 7, arranged peripherally about the plate 5, and a shaped lever 8, mobile between a position in which it engages a free end thereof in the cogging 7 and a position in which it does not interact with the cogging 7. With reference to figure 8, the shaped lever 8 is nudged by means for nudging (not illustrated) into the position in which it engages in the cogging 7, and is conformed in such a way as to prevent a free rotation of the plate 5 in a clockwise direction. The rotation in an anticlockwise direction of the plate 5, i.e. a rotation towards the unhooked position of the first attachment element 2, can happen only after displacement of the shaped lever 8 into the position in which it does not interact with the cogging 7.
The cam mechanism 4 blocking device advantageously further comprises a shaped key 8 predisposed to insert in a seating 10 and block the first attachment element 2 in a hooked-up position. The seating 10 is defined by a first portion, afforded on the first attachment element 2, and a second portion, afforded on the attachment counter-element 18. The portions face one another in the hooked-up position of the attachment elements, i.e. when the first attachment element 2 is engaged in the respective attachment counter-element 18 (figure 2). The shaped key 9 is provided with a security element 11 which is mobile between a position in which it engages to the attachment counter-element 18 and the key 9 cannot be extracted from the seating 10, and a position in which
the key 9 can be extracted from the seating 10. Preferably the security element 11 is constituted by a ring which is free to rotate with respect to the key 9 and to engage about a projection 11a solidly constrained to the attachment counter-element 18. Preferably the seating 10 is arranged on a plane that contains the longitudinal axes of the attachment elements 2, 3. In the illustrated embodiment, the cam mechanism 4 is activatable manually by means of a shaped key, schematically illustrated in figure 1. Any other means for activating can however be included, for example an electric or hydraulic motorised actuator. The attachment device of the invention is extremely simple both to realise and to use. The use of a cam mechanism for realising the movement between the attachment elements enables a considerable reduction to be made in the number of mechanical parts needed to build the device. The activation of the device is furthermore extremely simple inasmuch as it consists in a simple rotation of the support plate of the first attachment element, a rotation which very simply can be performed by hand, using a key. The elevated level of simplicity of the device obviously translates into a consistent economic advantage with respect to prior-art devices.
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