EP0151845B1

EP0151845B1 - Spacial structure

Info

Publication number: EP0151845B1
Application number: EP84300893A
Authority: EP
Inventors: Jose Maria Javier Galan Inchaurbe
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-02-13
Filing date: 1984-02-13
Publication date: 1988-05-11
Also published as: EP0151845A1; ATE34194T1; DE3471125D1

Abstract

A spacial structure comprising equidistantly positioned knuckles, a set of sections, (6) and means (16) for joining either end of said sections to said knuckles, where each knuckle is made up from two hollow base pieces (1) (2) whose outside shape is approximately that of a special shell in which there is a number of equidistantly positioned holes (3) at an angular distance of alpha with respect to one another, and where at least one of said base pieces possesses a perimeter area which is bent inwards, (12) and comprising means of attachment (5) between the first base piece and the second base piece which, upon being joined together and forming the knuckle of the special structure, allow all the equidistantly positioned holes to lie at an angular distance of alpha with respect to one another.

Description

This invention relates to a substantially spherical knuckle for a spacial structure, the knuckle being formed by two mating hollow base pieces which are joined together by connecting means and which are each provided with a plurality of holes for the attachment of one or more sections of the spacial structure. The holes in each mating base piece are equidistantly positioned with respectto one another at a predetermined angular distance.
US-A-4 027 449 shows a substantially spherical knuckle of this construction. A disadvantage however of the knuckle shown in that prior Patent is that the two mating hollow base pieces have outwardly-extending flanges which seriously inhibit the range of positions to be taken by connecting sections forming part of the spacial structure. One aim of the present invention therefore is to provide a substantially spherical knuckle which avoids this particular disadvantage.
A substantially spherical knuckle is also known from EP-A-0 081 608. In this case, however, the knuckle does not have connecting means at the joining area between the two mating base pieces. This leads to structural weakness in the knuckle so that it is a further aim of the present invention to produce a substantially spherical knuckle which avoids this disadvantage as well.
With these aims in mind, the present invention is directed to a substantially spherical knuckle of the construction outlined in the opening paragraph of this specification wherein one of the hollow base pieces is formed with an inwardly-bent perimeter lip while the other hollow base piece is formed with an outwardly-bent perimeter lip which faces and externally engages the lip so as to form a joining area-where the connecting means are located-between the two base pieces.
A knuckle of this construction avoids the two disadvantages mentioned above in connection with the prior art and therefore provides an improved form of spherical knuckle.
Examples of substantially spherical knuckles in accordance with the invention are shown in the accompanying drawings, in which-

Figure 1 is an elevational view of a knuckle in accordance with the invention wherein the lower base piece joining area covers the equator of the knuckle and wherein the screwed attachment between the two parts is effected upon said equator;
Figure 2 is a section of the screwed attachment when this is effected below the equator;
Figure 3 is a section of a knuckle where the screwed attachment is effected on the flat part of the joint area;
Figure 4 is a section showing the joining of the two base pieces by means of protrusions; and
Figure 5 is a section of the joint between a section member and a base piece.

The knuckle is comprised of two base pieces 1 and 2. Generally, base piece 1 is larger than base piece 2, giving an asymmetrical joint, but is is perfectly feasible for both pieces to be practically alike. The outside shape of the two base pieces is that of a spherical shell in order that its external form in the coupling is approximately a sphere.
Holes 3 provided upon each of the spherical shells are equidistantly positioned with respect to one another; and there is an angle α↑ between the adjoining edges of the different spherical shells when they lie together. (See Figure 3). These holes 3 form part of the joint between the spacial knuckle and sections 6. The angle α↑ can be altered for each knuckle and each different structure.
The first base piece 1 has a perimeter area 12 which is bent upon itself and is provided with open holes 13 which are preferably threaded. The holes 13 form part of the joint between the two base pieces 1 and 2. The other base piece 2 has, in turn, a lip 21 into which engages the lip 12 provided on base piece 1. In the drawings,the lip 21 is shown as engaging externally with lip 12, but the invention also includes the idea where lip 21 is given a similar shape to lip 12 so that the two can engage together by means of protrusions like those depicted in Figure 4.
Base piece 2 is provided with slots 21 bis which facilitate the engagement and joining with sections 6. Base piece 2 is furthermore provided, opposite the holes 13 on base piece 1, with open holes 13 bis, and joining screw 5 is housed in said holes 13 and 13 bis. Base piece 2 is moreover provided with protrusions 30 which engage in siots 31 arranged in base piece 1 (See Figure 4), although it is more logical to think of the reverse construction.
The knuckle of this spacial structure is completed with a strengthening member 7 which may be a tubular section one of whose ends abuts against the inside of poles 11 and 22. A stud 71 is provided inside said tube 7 whose head 23 abuts against pole 22 and, by means of nut 4, it abuts under pressure against pole 11, thus helping to secure base pieces 1 and 2 against one another.
Figure 5 shows a single-piece element 16 in revolution which is weld-attached at 15 to tubular section 6. Said single-piece element 16 has a conical frustrum side surface in order for it to suit different diameters of tube 6.
The tightening screw 20 has a head 8 which, either directly or by means of a widened area 9 or an additional member such as a washer having the same shape, is offered to the inside surface of base piece 1,2. The contact face of the widened area 9 is spherical so as to facilitate contact.
The single-piece element 16 has a face 10 which is offered to the outside face of the same base piece 1, 2, and said contact face is spherical as well for the reasons given.
Screw 20 and single-piece element 16 are threaded together in engagement, thus accomplishing the joint between tubular section 6 and base piece 1, 2. The design can also be such that the side surface 14' adjacent to the joining face 10 is shaped as a conical frustrum, thus preventing said contact face 10 from needing to be excessively large.
It is to be noted that the joining means comprised (a) of the strength member 8 with its stud 71 and fittings, and (b) of screw 5 in the engagement area, can be used either individually or together, and the presence of protrusions 30 is always optional.

Claims

1. A substantially spherical knuckle for a spacial structure, the knuckle being formed by two mating hollow base pieces (1, 2) which are joined together by connecting means (5, 30) and which are each provided with a plurality of holes (3) for the attachment of one or more sections (6) of the spacial structure, the holes (3) being equidistantly positioned at an angular distance (α↑) with respect to one another, characterised in that one (1) of the hollow base pieces is formed with an inwardly-bent perimeter lip (12) while the other hollow base piece (2) is formed with an outwardly-bent perimeter lip (21) which faces and externally engages the lip (12) so as to form a joining area-where the connecting means (5, 30) are located-between the two base pieces.

2. A knuckle according to claim 1, characterised in that an internal strengthening member (7) extends between and in contact with the respective poles (11, 22) of the base pieces (1, 2), there being tightening means (4, 71) for tightening the strengthening member (7) against the poles.

3. A knuckle according to claim 2, characterised in that the tightening means (4, 71) comprise a screw-threaded stud or bolt passing through a bore in the strengthening member (7) and through both base pieces (1, 2) at their poles (11, 22).

4. A knuckle according to any one of claims 1-3, characterised in that the connecting means (5, 30) comprise bolts or screws (5) which extend through holes in one (2) of the hollow base pieces in the joining area between them and screw into screw-threaded holes in the other hollow base piece (1).

5. A knuckle according to any one of claims 1-3, characterised in that one (2) of the base pieces has protrusions (30) which engage in slots (31) provided in the other base piece (1) at the joining area between them.

6. A knuckle according to any one of claims 1-5, having a section (6) of a spacial structure rigidly joined to it at one of the holes (3), characterised in that the section (6) includes a one-piece element (16) which is internally screw-threaded and which has a face (10) resting on the outer surface of one of the base pieces (1, 2).

7. A knuckle according to claim 6, characterised by a tightening screw (20) whose head rests on the inner surface of the base piece (1 or 2) and whose shank passes through the respective hole (3) so as to screw-threadedly engage the one-piece element (16).

8. A knuckle according to claim 7, characterised in that the contact areas (9, 10) between the single-piece element (16) and the screw-head (8) on the one hand and between the base piece (1 or 2) on the other hand are substantially spherical.

9. A knuckle according to any one of claims 6-8, characterised in that the one-piece element (16) is a body of revolution with at least one side surface shaped like a conical frustrum.