[0001] This invention relates to an improved metal joint, commonly known as a plate, for
fixing cylindrical metal legs to a table top. More specifically, the invention relates
to a joint of the type described in Italian patent 1,028,018.
[0002] As is well known to the expert of the art, in order to securely fix a tubular metal
leg to a table top it is necessary to provide an intermediate connection means between
the leg and table top able to effect a fixing between the two parts which is solid
and stable with time.
[0003] In addition, considering current market requirements, such a connection means should
have a structure which besides being of relatively simple and economical manufacture
does not require any complicated additional machining either at the top of the leg
or within the table top, but which at the same time allows quick assembly of the table
even by non-specialized personnel, hence enabling it to be despatched broken down
into its separate parts in packages of minimum overall size, leading to great cost
saving. The joint of the said Italian patent 1,028,018 solves the aforesaid problems
and consists of a single metal piece incorporating an expandable-wall boss (over which
a tubular metal leg can be easily mounted), with the boss there being associated a
circumferential flange with radial arms for fixing the joint to the table top by screws.
[0004] After being mounted over the expandable boss the tubular leg is securely fixed in
position by expanding the said walls, this expansion being achieved by tightening
a radial setscrew incorporated into the joint and accessible through a hole provided
in the leg. In this respect, the point of the setscrew acts during its tightening
on the opposing walls of the boss to expand them radially outwards so that they clamp
the inner surface of the metal leg by friction.
[0005] By loosening the setscrew the joint can be separated from the leg because of the
elasticity of the walls of the boss.
[0006] A joint system between tubular metal legs and a table top is hence obtained which
requires no additional machining of the various parts during assembly, which can be
achieved with no problem even by non-specialized personnel.
[0007] The aforedescribed joint constructed in accordance with the said Italian patent 1,028,018
has given perfectly satisfactory results.
[0008] The general object of the present invention is however to further improve this joint,
particularly with regard to its manufacturing time and cost.
[0009] In this respect, the threaded seat which receives the wall expansion setscrew is
formed by a separate operation involving drilling and tapping the body of the boss,
which itself is produced in one piece together with the circumferential flange and
radial arms by a die-casting operation.
[0010] The drilling and tapping of the boss of the joint after its die-casting involves
further handling and machining of the joint, so affecting its final cost.
[0011] Consequently the specific object of the invention is to provide a joint of the aforedescribed
type which is structured in such a manner as to be able to eliminate the said operation
involving the drilling and tapping of the seat for the expansion setscrew for the
boss walls.
[0012] This object is attained according to the present invention by a joint for securely
connecting a leg to a table top of the type comprising an expandable member insertable
into the complementary hollow top of said leg, an expansion setscrew screwed into
a threaded seat in said member and operable from the outside of the leg, and fixing
means at the top of the expandable member for fixing the table top to it, characterised
in that the seat for the setscrew consists of a plurality of internally threaded arcuate
sections which are positioned mutually circumferentially opposing and axially offset
so as to define, within said tubular seat, apertures adjacent to each of said arcuate
sections.
[0013] The structural and operational characteristics of the invention and its advantages
compared with the known art will be more apparent from the ensuing description given
with reference to the accompanying drawings, which show a joint incorporating the
inventive principles.
[0014] In the drawings:
Figure 1 is a top plan view showing the joint of the invention with the setscrew separate;
Figure 2 is an elevational view of the joint of Figure 1;
Figure 3 is a plan view from below; and
Figure 4 is a section on the line IV-IV of Figure 3.
[0015] In the drawings, the reference numeral 10 indicates overall the joint of the invention,
consisting preferably of an aluminium metal casting comprising an expandable member
in the form of a cylindrical boss 11, from the base of which there extends a circumferential
flange 12 provided with two arms 13. The flange 12 together with the arms 13 is intended
to be fixed by screws to a table top (not shown).
[0016] The cylindrical lateral wall of said boss 11 comprises along generating lines a plurality
of slits 14, they being three in number in the illustrated example, which extend into
respective radial slits 15 through the base 16 on the opposite side to that from which
said circumferential flange 12 extends.
[0017] The slits 14, 15 are spaced equiangularly apart by 120°, their purpose being to make
the boss 11 relatively yieldable in an elastic manner.
[0018] In the base 16, between two successive slits 15, there is a radial tubular seat into
which there is screwed a polygonally headed setscrew 17 which terminates in an expansion
point 18 with a tapered lead-in part 19.
[0019] Characteristically, said tubular seat is formed of three arcuate sections 20, internally
threaded as at 21, and positioned mutually circumferentially opposing and axially
offset to define apertures 22.
[0020] In this manner, said tubular seat, which is partially threaded internally, can be
directly formed during the casting of the joint without the need for subsequent costly
drilling and tapping of a solid part, as instead is required in the case of the joint
of said Italian patent No. 1,028,018.
[0021] The joint of the invention can be used in the same manner as the joint of Italian
patent No. 1,028,018.
1. A joint for securely connecting a leg to a table top, of the type comprising an expandable
member insertable into the complementary hollow top of said leg, an expansion setscrew
screwed into a threaded seat in said member and operable from the outside of the leg,
and fixing means at the top of the expandable member for fixing the table top to it,
characterised in that the seat for the setscrew consists of a plurality of internally
threaded arcuate sections which are positioned mutually circumferentially opposing
and axially offset so as to define, within said tubular seat, apertures adjacent to
each of said arcuate sections.
1. Verbindungselement zur sicheren Befestigung eines Tischbeines mit der Tischplatte,
das folgende Teile enthält
- ein räumlich ausdehnbares Teil, das in das dazugehörige Hohlteil des Beines einsetzbar
ist,
- eine vorspringende Feststellschraube, die in einem Gewindesitz in dem räumlich ausdehnbaren
Teil eingeschraubt ist und von der Außenseite des Tischbeines gehandhabt werden kann
und
- Befestigungsmittel im oberen Bereich des räumlich ausdehnbaren Teils zur Fixierung
an der Tischplatte
dadurch gekennzeichnet,
daß der Sitz der Feststellschraube aus mehreren mit Innengewinde versehenen bogenförmigen
Abschnitten besteht, welche wechselseitig gegenüberliegend am Außenumfang und axial
fortlaufend angeordnet sind, so daß sich, innerhalb des röhrenförmigen Schraubensitzes,
benachbart zu jedem bogenförmigen Gewindeabschnitt ein Durchbruch befindet.
1. Articulation destinée à relier solidement un pied a un dessus de table, du type comprenant
un élément expansible susceptible de s'insérer dans le sommet creux complémentaire
du pied, une vis d'expansion vissée dans un siège fileté de l'élément et pouvant être
actionnée de l'extérieur du pied, et des moyens de fixation, au sommet de l'élément
expansible, destinés à fixer le dessus de table à celui-ci, caractérisée en ce que
le siège de la vis de réglage est constitué d'une pluralité de sections courbées présentant
un filet intérieur, qui sont positionnées de façon circonférentiellement opposée et
axialement décalée afin de définir, à l'intérieur du siège tubulaire, des ouvertures
adjacentes à chacune des sections courbées.