Segment of an articulated arm and articulated arm comprising said segment

Abstract

Segment of an articulated arm made of composite material, with an elongated shape defining a longitudinal axis, and having a box-like cross section. The segment includes a first end portion, configured for the pivoting of a further segment, a second intermediate portion configured for the pivoting of an actuation member, and a third end portion. The first, second and third portions are made in a single body. The second intermediate portion includes a protruding zone defined by a first side and by a second side converging with respect to each other to define a top. Pivoting elements are provided in the protruding zone for the pivoting of the actuation member between the protruding zone and the first end portion. The first and the second side defining the protruding zone are filleted to substantially rectilinear adjacent tracts of the first and third end portions.

Claims

1. Segment of an articulated arm made of fiber reinforced composite material, said segment with an elongated shape defining a longitudinal axis, and having a box-like cross section, and comprising at least a first end portion, suitable to allow the pivoting of an associated further segment, a second intermediate portion configured to allow the pivoting of an actuation member, and a third end portion wherein said first end portion, said second intermediate portion and said third end portion are made in a single body with respect to each other, wherein said second intermediate portion comprises at least a protruding zone defined at least by a first side and by a second side converging with respect to each other to define a vertex, wherein said protruding zone of the intermediate portion is defined by a closed box-like cross section, wherein portions disposed respectively on one side and the other of the protruding zone have a one-directional disposition of the fibers that is parallel to the longitudinal direction of the segment, first pivoting elements being provided in said protruding zone in order to allow the pivoting of said actuation member between said protruding zone and the first end portion, wherein said first end portion is provided at least with second pivoting elements configured to allow the connection of associated articulation elements between said actuation member and the associated further segment, wherein said first and said second side defining the protruding zone are filleted to substantially rectilinear adjacent tracts of said first and third end portions, said rectilinear tracts being substantially parallel to the longitudinal axis, and wherein the angle (α) defined between first side and rectilinear tract of the first end portion is bigger than the angle (β) defined between second side and rectilinear tract of the third end portion, said angle (β), defined between said second side and said rectilinear tract of the third end portion, being comprised between 5° and 25°, with respect to the longitudinal axis, said second side being filleted to said rectilinear tract of the third end portion with a filleted tract, wherein said second side and said filleted tract extend overall for a first longitudinal length of said second intermediate portion, and in that the ratio between the rounding radius of said filleted tract and said first length is comprised between 1.8 and 7.2.

2. Segment as in claim 1, wherein said first end portion and second intermediate portion are defined at least by an intrados surface and by an extrados surface and in that said first pivoting elements are disposed protruding with respect to the intrados surface of the cross section of said first end portion.

3. Segment as in claim 2, wherein in the intrados surface, and in correspondence to said first side, at least a through cavity is made to allow the insertion through it of said actuation member.

4. Segment as in claim 1, wherein said angle (α) defined between said first side and said rectilinear tract of the first end portion is comprised between 25° and 50.

5. Segment as in claim 4, wherein said angle (α) defined between said first side and said rectilinear tract of the first end portion is comprised between 30° and 45°.

6. Segment as in claim 5, wherein said angle (α) defined between said first side and said rectilinear tract of the first end portion is comprised between 35° and 40°.

7. Segment as in claim 1, wherein said first pivoting elements and said second pivoting elements are distanced from each other by an axial distance, parallel to said longitudinal axis, and by a transverse distance, and in that the ratio between said axial distance and said transverse distance is comprised between 3.9 and 15.6.

8. Segment as in claim 7, wherein the ratio between said second length and said axial distance is comprised between 0.15 and 0.65.

9. Segment as in claim 8, wherein the ratio between said second length and said axial distance is comprised between 0.25 and 0.55.

10. Segment as in claim 9, wherein the ratio between said second length and said axial distance is comprised between 0.30 and 0.50.

11. Segment as in claim 7, wherein the ratio between said axial distance and said transverse distance is comprised between 4.5 and 12.

12. Segment as in claim 11, wherein the ratio between said axial distance and said transverse distance is comprised between 6 and 10.

13. Segment as in claim 1, wherein said second intermediate portion comprises a filleted tract interposed between said first portion and said first side, and in that said filleted tract and said first side extend overall for a second longitudinal length.

14. Segment as in claim 13, wherein the ratio between said second length and said axial distance is comprised between 0.15 and 0.65.

15. Segment as in claim 1, wherein said angle (β) defined between second side and said rectilinear tract of the third end portion, is comprised between 10° and 20° with respect to the longitudinal axis.

16. Segment as in claim 1, wherein the ratio between the rounding radius of said filleted tract and said first length is greater than 3.5.

17. Articulated arm comprising at least a segment made of fiber reinforced composite material, with an elongated shape defining a longitudinal axis, and having a box-like cross section, and comprising at least a first end portion, suitable to allow the pivoting of a further segment being pivoted to said first end portion of the segment, a second intermediate portion configured to allow the pivoting of an actuation member, and a third end portion wherein said first end portion, said second intermediate portion and said third end portion are made in a single body with respect to each other, wherein said second intermediate portion comprises at least a protruding zone defined at least by a first side and by a second side converging with respect to each other to define a vertex, wherein said protruding zone of the intermediate portion is defined by a closed box-like cross section, wherein portions disposed respectively on one side and the other of the protruding zone have a one-directional disposition of the fibers that is parallel to the longitudinal direction of the segment, first pivoting elements being provided in said protruding zone in order to allow the pivoting of said actuation member between said protruding zone and the first end portion, wherein said first end portion is provided at least with second pivoting elements configured to allow the connection of articulation elements between said actuation member and said further segment, wherein said first and said second side defining the protruding zone are filleted to substantially rectilinear adjacent tracts of said first and third end portions, said rectilinear tracts being substantially parallel to the longitudinal axis, and wherein the angle (α) defined between first side and rectilinear tract of the first end portion is bigger than the angle (β) defined between second side and rectilinear tract of the third end portion, said angle (β), defined between said second side and said rectilinear tract of the third end portion, being comprised between 5° and 25°, with respect to the longitudinal axis, said second side being filleted to said rectilinear tract of the third end portion with a filleted tract, wherein said second side and said filleted tract extend overall for a first longitudinal length of said second intermediate portion, and in that the ratio between the rounding radius of said filleted tract and said first length is comprised between 1.8 and 7.2.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other characteristics of the present invention will become apparent from the following description of one form of embodiment, given as a non-restrictive example with reference to the attached drawings wherein:

(2) FIG. 1 is a lateral view of a segment according to the present invention, applied to a portion of an articulated arm;

(3) FIG. 2 is a partial prospective view of the segment according to the present invention;

(4) FIG. 3 is an enlarged lateral view of a portion of the segment in FIG. 1.

(5) To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings.

DETAILED DESCRIPTION OF ONE FORM OF EMBODIMENT

(6) With reference to FIG. 1, a segment of an articulated arm 11 is indicated in its entirety by the reference number 10 and is configured to be pivoted at a first end 12 with a first other segment 15 and at its second end 13 with a possible other second segment, not shown in the drawings.

(7) The segments 10, 15 are made of composite material, that is, carbon, glass aramid or other fibers, made solid with each other by resins.

(8) The segment 10 has a rectangular section, hollow inside, and develops longitudinally according to a longitudinal axis Z.

(9) The section of the segment 10 (FIG. 2) has a width L which is substantially uniform along the whole longitudinal extension, and a height H that varies along the longitudinal extension.

(10) The segment 10 (FIG. 1) has an intrados surface 19 and an extrados surface 20 which is substantially parallel to the longitudinal axis Z.

(11) The segment 10 according to the present invention is defined, starting from the first end 12 and in succession along the longitudinal axis Z, by at least a first end portion 21, a second intermediate portion 22 and a third end portion 23 made in a single body.

(12) The first end portion 21 (FIGS. 2 and 3), or pivoting portion, is defined by a substantially rectilinear tract 42, has the height H of the cross section uniform along its axial development, and is provided with a pair of first pivoting bushings 26 and a pair of second pivoting bushings 27 associated in correspondence with the first end 12.

(13) The third end portion 23 also comprises, adjacent to the second intermediate zone 22, a substantially rectilinear tract 43.

(14) The first end 12 is substantially fork shaped, and the first segment 15 is introduced through it.

(15) The first 26 and second bushings 27 are recessed in the two sides of the fork.

(16) The first segment 15 pivots in the first bushings 26 by means of a pin, while two opposite brackets 29, only one of which is visible in FIG. 1, pivot in the second bushings 27.

(17) The brackets 29 are provided with three pivoting holes 30 in each of which the segment 10, the end of the piston 131 of an actuation member 31 and a second connection staff, not visible in the drawings, respectively pivot.

(18) The second connection bracket in turn pivots on the first segment 15, and provides to articulate the segment 10 and the first segment 15 with respect to each other.

(19) The actuation member 31, in this case a hydraulic actuator, pivots with the end of its cylinder 231 in correspondence with the second intermediate portion 22 of the segment 10.

(20) The second intermediate portion 22, or attachment portion of the actuation member 31, has a height H of the cross section that varies along the longitudinal axis Z, to define a zone protruding with respect to the intrados surface 19 of the segment 10.

(21) More specifically, on the intrados side of the segment 10, the second intermediate portion 22 has a first side 33 facing toward the first end 12 and a second side 34 inclined and converging toward the first side 33 to define together a vertex 35, which is advantageously rounded or with a rounded connection.

(22) In correspondence with the first side 33 a through cavity 36 is made, configured to allow an end portion of the actuation member 31 to be inserted through it.

(23) In the second intermediate portion 22 third pivoting bushings 39 are integrated, in which the other end of the actuation member 31 is pivoted.

(24) The third bushings 39 are integrated in the second intermediate portion 22 of the segment in an external position with respect to the intrados surface 19, so as to allow connection of the actuation member 31.

(25) The first side 33 (FIG. 3) is inclined with respect to the rectilinear tract 42, connecting to the first end 12, by a first angle α comprised between 25° and 50°, preferably between 30° and 45°, even more preferably between 35° and 40° with respect to the longitudinal axis Z.

(26) The second side 34 is inclined with respect to the rectilinear tract 43 connecting to the second end 13 by a second angle of inclination β comprised between 5° and 25°, preferably between 10° and 20°, even more preferably by about 15° again with respect to the longitudinal axis Z.

(27) The second angle of inclination β is in any case less than the first angle α, thus ensuring a gentler connection between the protruding zone and the second end 13, which is the end opposite the one where the actuation member 31 articulates.

(28) In particular, the inclination of the second side 34 is a good compromise between the mechanical resistance properties required for the sections in that tract and the need to reduce the overall bulk so as to allow the overall reduction of the articulated arm 11 in its closed configuration.

(29) A very reduced amplitude of the second angle of inclination β, although advantageous with regard to the reduction in intensification of tensions, would not allow the compact closure of the articulated arm 11. To this must also be added a greater quantity of material with consequent increase of the overall weight.

(30) The first side 33 (FIG. 3) of the second intermediate portion 22 connects to the first end portion 21, and in particular to its rectilinear tract 42, with a first filleted tract 40 having a first rounding radius R1.

(31) The second side 34, on the contrary, connects to the third end portion 23, and in particular to its rectilinear tract 43, with a second filleted tract 41 having a second rounding radius R2.

(32) The third bushings 39 are distanced by a determinate axial distance X and by a determinate transverse distance Y with respect to the interaxis of the second bushings 27. The ratio between the axial distance X and the transverse distance Y is comprised between 3.9 and 15.6, preferably between 4.5 and 12, even more preferably between 6 and 10.

(33) The pivoting axis of the second bushings 27 is displaced vertically, toward the intrados and with respect to the longitudinal axis Z, by a determinate gap G, comprised between 0.01 and 0.2 times the height H.

(34) This allows to use second bushings 27 with an optimized diameter so as to suitably distribute uniformly the pressures that are generated when the actuation member 31 is driven.

(35) The second side 34 and the second filleted tract 41 develop overall for a determinate first longitudinal length E of the second portion 22.

(36) According to one feature of the invention, the ratio between the second rounding radius R2 and the first length E is comprised between 1.8 and 7.2, preferably more than 3.5. This ratio allows to optimize the mechanical resistance of the cross sections and the sizes of the segment 10, obtaining similar advantages with respect to what we described before for the second angle of inclination β.

(37) The first side 33 and the first filleted tract 40 develop overall for a determinate second longitudinal length S of the second intermediate portion 22.

(38) In order to reduce the quantity of material required to make the segment 10 in said zone, and to prevent the actuation member 31 from remaining contained inside the segment 10, it is advantageous to provide that the ratio between the second length S and the axial distance X is comprised between 0.15 and 0.65, preferably between 0.25 and 0.55, even more preferably between 0.30 and 0.50.

(39) The first bushings 26 are offset axially by a distance P with respect to the second bushings 27. The distance P is about 0.8-1.2 times the height H of the cross section of the first end portion 21. This allows to contain the overall length of the first end portion 21, preventing useless waste of material.

(40) In some advantageous forms of embodiment, it is provided that the second intermediate portion 22 has a particular disposition of the fibers of which it consists, different from that of the first end portion 21 and of the third end portion 23, in order to confer on this portion greater resistance to stress.

(41) It is clear that modifications and/or additions of parts may be made to the segment as described heretofore, without departing from the field and scope of the present invention.

(42) It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of segment, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.