WO1994027906A1

WO1994027906A1 - Joint and joint driving system, with three pull points, for arms of jib cranes and aerial platforms

Info

Publication number: WO1994027906A1
Application number: PCT/IT1994/000065
Authority: WO
Inventors: Savino Pasquali
Original assignee: Savino Pasquali
Priority date: 1993-05-24
Filing date: 1994-05-20
Publication date: 1994-12-08
Also published as: ITMC930035A1; ITMC930035A0; AU6980494A; IT1267042B1

Abstract

The joint and the system for driving thereof include an articulated quadrilateral formed by two groups (C, D) of pairs of tie-rods, with the tie-rods of each group hinge joined so as to define a first corner of the quadrilateral at the connection axis of two segments (A, B) of an arm, and a second corner (21) opposite to the first corner. The remainder of the tie-rods ends of each group are hinge joined to corresponding ends of the tie-rods of the other group, so that the hinge points common to the two groups form the other two opposite corners (22, 23) of the quadrilateral. Two cylinders (1, 2) are respectively hinged to the segments (A, B) and act on the two corners (22, 23) formed by the hinge points common to the tie-rods of the first group and the tie-rods of the second group, while a third cylinder (5) is hinged to the connection axis (20) of the two segments and acts on the opposite corner (21) of the quadrilateral, i.e. on the hinge point common to the tie-rods of the second group.

Description

JOINT AND JOINT DRIVING SYSTEM, WITE THREE PULL POINTS, FOR ARMS OF JIB CRANES AND AERIAL PLATFORMS.

TECHNICAL FIELD The present invention is concerned with the technical field related to the construction of jib cranes and aerial work platforms, which are mostly mounted on self -moving vehicles and trucks which are suitably adapted. More particularly the present invention concerns a joint for the arm of jib cranes and aerial platforms, and an driving system for the articulation that is formed by this joint .

BACKGROUND ART

Presently, there are available on the market jib cranes and_, aerial work platforms capable of reaching considerably high levels by means of arms which are formed by a series of segments, e.g. three segments.

The segments may be telescopically made longer and are articulated to each other by means of suitable joints.

The joints presently in use allow for opening two adjacent segments through an angle that cannot be greater than 180 degrees, because the extreme position that can be obtained is the one in which the two adjacent segments are lined up.

The necessity of collapsing the crane, during transportation or travels of the vehicle on which the crane is mounted, so as to keep it within the size limits as provided by law, so as to allow for free circulation, obliges to use two joints which are set in such a way that the segments of the arm move according to opposite directions. In this way, the three segments making up the jib crane arm, result in being positioned one over the other when the crane is not in operation.

With this conventional system, that includes only one pull point, the first segment of the arm cannot be set parallel to the third one, but only when the jib crane or platform is out of operation and in position for transportation, as it appears from Figure 7b in which an arm made in accordance with the prior art is shown.

Consequently, this leads to great limitation in using the jib crane or aerial platform thus bringing about obstacles which cannot be overcome in certain particular situations. These obstacles occur, for instance, when the necessity arises of working on the opposite facing of a house passing with the arm of the jib crane or aerial platform over the roof, or when the necessity occurs of working under a bridge with the vehicle parked over the bridge, thus encountering, in this last case, a greater limitation for the strokes of the arm.

DISCLOSURE OF THE INVENTION The object of the present invention is to propose a joint for the arm of jib cranes and aerial work platforms, that allows for positioning the segments of the arm one over the other, by rotating the second segment in opposite direction with refer- ence to the third segment, but forming angles be¬ tween them ranging up to 270 degrees.

The articulation that is formed in correspon¬ dence with the joint proposed herein, can be driven by three pull points and allows for positioning the third segment parallel to the first while forming two consecutive angles, the first being 90 degrees while the second 270 degrees, in both semi-planes delimited by the first segment.

The joint that is the subject of the present invention is designed to be used in the construction of arms for jib cranes and aerial work platforms, which arms each includes a series of at least two adjacent segments, namely a first segment and a second segment, which are joined to each other in correspondence with a hinge connection axis, so that they can rotate about this axis.

The joint and the system for the driving thereof include: an articulated quadrilateral formed by two groups of pairs of tie rods, with the tie rods of each group hinge joined to each other at a common point with respective ends, so as to define a first corner of the quadrilateral coincident with the connection axis of the two adjacent segments, as well as a second corner of the same quadrilateral opposite to the first corner, while the remainder of the ends of the tie rods of the first group are hinge joined to corresponding ends of the tie rods of the second group, so that each pair of tie-rods form a side of the articulated quadrilateral, and that the hinge connection points which are common to both groups of pairs of tie-rods form the other two opposite cor¬ ners of the articulated quadrilateral; a first cylinder, or pair of cylinders, hinged to the first segment and acting with its stem, or pair of stems, on a corner of the articulated quadrilat¬ eral formed at the hinge connection point common to the tie-rods of the first pair of the first group and the tie-rods of the first pair of the second group; a second cylinder, or pair of cylinders, hinged to the second segment and acting with its stem, or pair of stems, on a corner of the articulated quadrilat¬ eral formed at the hinge connection point common to the tie-rods of the second pair of the first group and the tie-rods of the second pair of the second group; a third cylinder, or pair of cylinders, hinged to the connection axis of the two adjacent segments, and acting with its stem, or with their stems, on the opposite corner of the articulated quadrilat¬ eral, i.e. on the hinge connection common to the tie-rods of the second group.

BRIEF DESCRIPTION OF THE DRAWINGS

The characteristics of the invention will be pointed out in the following description, with particular reference to the attached drawing, in which: - fig. 1 shows a lateral view of the joint, being the object of the present invention, forming the articulation between two consecutive segments of an arm of jib crane or aerial platform;

- fig. 2 shows the same view of the joint in a subsequent opening phase (90 degrees) ;

- fig. 3 shows the same, lateral, view of the joint in a subsequent opening phase (180 degrees) ;

- fig. 4 shows the same, lateral, view of the joint in a subsequent opening phase (270 degrees) ; - fig. 5 shows, according to a section plane V-V of the fig. 2, the way of connecting the cylinders with the relative segment;

- fig. 6 shows the view of the joint in subject according the arrow F of the fig. 3; - fig. 7a shows several configurations that can be obtained with an arm formed by three telescopic segments connected by joints constructed according to the present invention;

- Fig 7b shows a few configurations obtainable with an arm formed by three telescopic segments connected by joints constructed according to the prior art.

BEST MODE OF CARRYING OUT THE INVENTION

With reference to the above listed figures, the reference numerals 1 and 2 indicate the cylin¬ ders, or the pairs of cylinders la, lb and 2a, 2b as seen in figures 5 and 6, hinge connected with their outer casing to two adjacent segments A and B re¬ spectively, which form an arm 10, by connection flanges 11 made integral with the same segments.

The hinge connection between the cylinders and the correspondent segment is made by means of pins 13 that engage with the outer casing of the cylinders la, lb, 2a, 2b and with the respective flanges 11.

In the following, for the simplicity sake, the reference will be made to only one cylinder for each pair.

The stems 3 and 4 of the cylinders 1 and 2 are connected to the opposite corners of an articu¬ lated quadrilateral 14 formed by two groups C, D of pairs of tie-rods.

The tie-rods of each group are hinge joined one to the other at one end; in particular, the pairs of tie-rods 15a, 15b, 16a, 16b of the group C, are hinge joined in correspondence with the connec¬ tion axis 20 of the two segments A and B.

The tie-rods 17a, 17b, 18a, 18b of the second group D, are hinge joined one to another forming a second corner 21 of the articulated quadrilateral 14.

Also in this case, for simplicity sake, the reference will be made to tie-rods of each pair as to single tie-rods 15, 16, 17, and 18. The remaining ends of the tie-rods of the group C are hinge-joined with the remaining ends of the correspondent tie-rods of the opposite group D, so that each tie-rod, or pair of tie-rods, forms a side of said articulated quadrilateral 14 and the points of hinge connection of the two groups of tie- rods form the other two opposite corners 22 and 23 of the same articulated quadrilateral 14.

The stems 3 and 4 of the two cylinders 1 and 2 are connected respectively to two opposite corners 22 and 23 common to the two groups C and D.

A third cylinder 5, or a pair of cylinders 5a, 5b, is connected between the corner hinged to the conjunction axis 20 of the two segments of the arm, and the opposite corner 21 of the articulated quadrilateral 14, situated on the diagonal of the quadrilateral perpendicular to the diagonal joining the two corners connected to the stems 3 and 4, of the cylinders 1 and 2.

Therefore, the two cylinders 1 and 2 act on two pull points, coincident with the corners 22 and 23 of the articulated quadrilateral 14, common to the two groups of tie-rods.

Sending oil under pressure to the cylinders 1 or 2, by means of a suitable hydraulic .unit and the relative controls, the movements of the respective stems are determined, by opening or closing the two adjacent segments of the arm.

For instance, activating the cylinder 2 makes the stem 4 return according to the direction G of figure 1, thus determining the rotation of the segment B according to the direction Rl.

The segment B takes different subsequent positions, one of which is shown with dashed line in figure 1, until it reaches the configuration of fig. 2, i.e. 90 degrees vertical in respect to the seg¬ ment A.

Then, the cylinder 1 is actuated, making the stem 3 return according to the direction H of figure 2 determining the rotation of the segment B, accord- ing to the direction R2, until the segment B is lined up with the segment A, i.e. at 180 degrees in respect with the latter (fig. 2) .

At this point, the third cylinder 5 is acti¬ vated determining the variation of the diagonals of the articulated quadrilateral 14, as shown with dashed line in fig. 3.

The stem ^~ of the cylinder 5 extends in the direction J determining the continuation of the opening movement of the segments, making the segment B rotate over 180 degrees according to the direction R3.

In particular, the lengthening of the diago¬ nal between the corner of the quadrilateral hinged to the connection axis 20 of the segments and the opposite corner 21, can continue as much as the size of the components allows for it, that is to say, until an opening angle, of at least 270 degrees, between the adjacent segments, is reached, as shown in fig. 4. As a matter of fact, the stem of the third cylinder 5 acts on a third pull point, marked by the corner 21 of the quadrilateral opposite to the corner hinged to the conjunction axis 20 between the two segments A and B. Then, the third pull point acts on the first two pull points 22 and 23 due to the articulation of the quadrilateral.

INDUSTRIAL APPLICABILITY By positioning two joints of this type so as to connect, one to another, three segments that form the arm of a jib crane or of a aerial work platform, it is possible to obtain many arrangements of the same arm, many more than can be obtained with an arm articulated by traditional joints with one pull point.

In particular, as seen in figure 7, it is possible to place the free end of the third segment of the jib crane or of the movable platform in an indefinite number of positions distributed in the whole zone surrounding the supporting vehicle, even at the level lower than the level at which the vehicle is parked, or far from the obstacles, e.g. buildings, thus making it possible to reach zones inaccessible up till now.

The latter possibility is obtained by e.g. turning the first segment upwards, opening the second one at 90 degrees in respect to the first, and opening the third at 270 degrees in respect to the second, thus obtaining a "U"-like arm.

Alternatively, the second segment can be opened at 270 degrees with respect to the first, and the third segment can be opened at 90 degrees with respect to the second, thus obtaining a "U"-like configuration for the arm, but in the opposite semi- plane, with respect to the first segment.

It is possible to work under a bridge, over which the supporting vehicle is parked, by orienting the first segment horizontally, or inclined down- wards, then orienting the second segment vertically downwards and the third segment at 90 degrees or 270 degrees in respect to the second, in order to posi- tion the free end of the arm either on one side or on the other in respect to the same segment.

In general, all the positions obtainable with various orientations of the first segment are pos¬ sible, with the orientations at the angle comprised between 0 degrees and 270 degrees of the second segment in respect to the first and with the orien¬ tation, still according to an angle comprised be¬ tween 0 and 270 degrees, of the third segment in respect to the second.

Claims

1) Joint, and the system for driving thereof, for arms of jib cranes or aerial work platforms, each of said arms comprising a series of at least two adja¬ cent segments (A,B) , first and second respectively, which are joined to each other at a hinge connection axis (20) , so that they can rotate about said con¬ nection axis, said joint and the system for driving thereof being characterised in that they comprise: a articulated quadrilateral (14) formed by two groups (C,D) of pairs of tie-rods (15a, 15b, 16a, 16b, 17a, 17b, 18a, 18b) , with the tie-rods of each group hinge joined to each other at a common point with respective ends, so as to define a first corner

(20) of the quadrilateral coincident with the said connection axis (20) of the said two adjacent seg- ments (A,B) , as well as a second corner of the same quadrilateral opposite to the first corner (20) , while the remainder of the ends of the tie rods of the first group are hinge joined to corresponding remainder ends of the tie rods of the second group, so that each pair of tie-rodε form a side of said articulated quadrilateral (14) and that the hinge connection points which are common to both groups of pairs of tie-rods form the other two opposite cor¬ ners of the articulated quadrilateral; a first cylinder (1), or pair of cylinders (la,lb), hinged to the first segment (A) and acting with its stem (3) , or pair of stems, on a corner (23) of the articulated quadrilateral (14) formed at the hinge connection point common to the tie-rods (16a,16b) of the first pair of the first group and the tie-rodε (18a,18b) of the first pair of the second group; a second cylinder (2), or pair of cylinders (2a,2b), hinged to said second segment (B) and acting with its stem (4) , or pair of stems, on a corner (22) of the articulated quadrilateral (14) formed at the hinge connection point common to the tie-rods (15a, 15b) of the second pair of the first group and the tie-rods (17a, 17b) of the second pair of the second group; a third cylinder (5), or pair of cylinders (5s, 5b), hinged to the connection axis (20) of the said two adjacent segments, and acting with its stem (6) , or with their stems, on the opposite corner (21) of said articulated quadrilateral (14) , i.e. on the hinge connection between the tie-rods (17a, 17b, 18a, 18b) of the cited second group (D) .

2) Joint and the system of driving thereof, accord¬ ing to claim 1, characterised in that the cylinders (la, lb, 2a, 2b, 5a, 5b) , for driving the articula¬ tion formed in correspondence with said joint are operated by one unique control.

3) Joint and the system of driving thereof, accord- ing to claim 1, characterised in that the cylinders

(la, lb, 2a, 2b, 5a, 5b) , for driving the articula¬ tion formed in correspondence with said joint are operated by separate controls for each cylinder, or pair of cylinders.