[0001] This invention relates to bellows-like collapsible canvas coverings which are widely
used to keep selectively sheltered or uncovered certain areas, like for instance
tennis courts, commercial storage areas and so on, depending upon the variations of
the weather conditions. Said collapsible canvas coverings substantially comprise
a waterproof canvas supported by a plurality of mutually parallel arches connected
to each other by means of pantograph linkages and capable of being brought closer
or apart, being driven by a preferably electric motor. When the arches are moved apart
from each other they drag the canvas therewith, whereby said canvas is extended to
cover the sheltered area; to uncover the same area, it is just enough to take the
arches back closer to each other, and the canvas folds in a bellows-like fashion.
The pantograph linkages presently used to connect the arches to each other comprise,
in the simplest embodiment thereof, two rods centrally pivoted to each other like
a St.Andrews' cross, each rod having the lower end thereof pivotally connected to
the base of an arch, and the upper end thereof terminating with a sleeve which is
slidably mounted on a vertical rod fastened at both ends thereof to the adjacent
arch. When two adjacent arches are moved closer the pantograph linkage rods close
up as a scissor, and the upper ends thereof slide upwards along said vertical rod.
When the arches are moved apart, the pantograph linkage rods open in a scissor-like
fashion and the ends thereof slide downwards along the vertical rods, while the lower
ends move apart from the arches they are pivoted to, causing the hinges to open up.
[0002] As it is known, when the arches are moved closer and the canvas gets folded in a
bellows-like fashion, the bellows folds end up being caught between the rods of each
pantograph linkage and said rods, while closing in a scissor-like fashion, may damage
or in the worst case tear the canvas. In order to avoid said drawback, it is necessary
to provide, close to the pantograph linkage, suitable protection means, like for instance
horizontal rods, in order to keep the bellows folds from being caught between the
pantograph linkage rods. Another serious drawback of the known pantograph linkages
is the injuries they can originate. In fact, if an operator leaves absent-mindedly
his hand lying on a pantograph linkage, during uncovering of the sheltered area, he
is subjected to the risk of having his hand cut off by the pantograph linkage components
while they are closing in a scissor-like fashion and they are mutually approaching
up to a point wherein they are actually contacting each other.
[0003] It has now been devised, and it is the object of this invention, a new collapsible
canvas covering wherein the arches are connected to pantograph linkages which, upon
closing, leave between each element and the adjacent one, enough room to receive the
fold of the bellows-like folding canvas. In the simplest embodiment thereof, said
pantograph linkage comprises two mutually pivoted rods, the pivot being at the mid-point
of the rods, in a known St.Andrews' cross fashion, said rod being bent at the pivoting
area, whereby the arm, upstream from said bend lies in a position offset relative
to the other arm and relative to the pivot pin. Due to that offset arrangement, when
the pantograph linkage is closed, the arms of each pantograph linkage member will
be located apart from each other and the room available will be able to receive the
canvas fold without any damage to the latter. The amount of offset should be determined
as a function of the room needed to receive the canvas fold.
[0004] With the pantograph linkage according to this invention, the canvas is never damaged,
and the room available between the linkage members allows the folded canvas to find
enough room when normally pushed between said members either by gravity or by the
wind. Said room is also sufficient in order to avoid injuring or cutting the operator
fingers, if he had inadvertently laid his hand between the pantograph linkage members
when the arches are brought together.
[0005] Further features and advantages of the pantograph linkage according to this invention
will become apparent to those skilled in the art from the following detailed description
of an embodiment thereof, referring to the attached drawings, wherein:
Figure 1 is a perspective view of a collapsible canvas covering according to this
invention, arranged above a tennis court, and shown in an open position;
Figure 2 shows an enlarged detail view, taken from the inside, of the area of the
canvas covering included within the hatched rectangle A of Figure 1;
Figure 3 shows a member of the pantograph linkage of the canvas covering according
to this invention,in a collapsed position, and in front view;
Figure 4 shows a front view of a different embodiment of a pantograph linkage element
of the canvas covering of this invention, and
Figure 5 shows an elevational side view of the pantograph linkage unit of Figure 4.
[0006] Referring now to Figure 1, there is shown a canvas covering according to this invention
mounted above a tennis court and kept in an open position. Said canvas covering comprises
substantially a canvas 1 of waterproof material, supported by a plurality of metal
arches 2 whose bases are mounted on wheels which are able to roll on guides 3 lying
on the ground. A door 4 is provided for entrance underneath the canvas covering when
it is in a closed position. A motor drives arches 2 to move closer or apart from each
other, with a corresponding partial or total collapsing or closure of the collapsible
canvas covering. In the position shown in the Figure, arches 2 have been brought together,
in two groups, each group corresponding to a half of the canvas covering, whereby
the collapsible covering is in a collapsed position. Only the first arch 2 of each
half canvas covering is not close to the others, in that it is directly connected
to the motor and has a guiding and dragging function for all the other arches connected
thereto. The connection between arches is provided in a known way, by means of a pantograph
linkage comprising two rods pivoted to each other in a St. Andrews' cross fashion,
which have been improved according to this invention, as it will be described in detail
referring to the following Figures.
[0007] In Figure 2 which shows, in an enlarged view, taken from inside the court, the part
of collapsible canvas covering included in the rectangle shown in hatched line in
Figure 1, as it is shown, every arch 2 is provided at the lower end thereof with a
wheel 5 and, at a certain height above the ground, also with a vertical bar 6 carrying
a sleeve mounted thereon and able to slide on said rod. Each arch 2 is connected to
the adjacent one by me of a pantograph linkage unit comprising rods 7, 7′ centrally
and rotatably pivoted to each other, at pivot pin 8. Rod 7 has the lower end thereof
pivoted to an arch 2 at a hinge 10, while the opposite end thereof is fastened to
sleeve 18 slidingly mounted within vertical bar 6 associated with adjacent arch 2′.
Rod 7′ in turn has the lower end thereof pivoted to said adjacent arch at pivot point
9, while the upper end thereof is fastened to sleeve 17 slidably mounted on vertical
bar 6 of arch 2 whereto rod 7 is pivoted at point 10. Between pairs of arches where
is shown folds 11 of canvas 1, folded in a bellows-like fashion.
[0008] As it is shown in Figure 2, between each pantograph linkage member according to this
invention there is provided enough room to receive each canvas fold 11, whereby the
canvas cannot get damaged when the collapsible canvas covering is in a collapsed position,
as it would have been instead the case if the collapsible canvas covering had been
provided with a pantograph linkage according to the previous art. Referring now to
Figure 3, there is shown how rods 7, 7′ according to this invention have been modified
compared to the state of the art, in order to obtain the improved pantograph linkage
according to this invention. Rod 7, whose cross section can be square, rectangular
or round, is bent in the middle part thereof, wherein it has an opening 14 adapted
to receive a pivot pin 8 by means of which rod 7 is pivotally connected to rod 7′.
Due to said bent configuration, rod 7 is divided into two sections: an arm 15 located
above or upstream said central area 13, and arm 16 located below or downstream from
said central region 13. Similarly, rod 7′ as well is divided into two sections: an
arm 15′ located above central area 13′ and an arm 16′ located below said central area.
Arms 15 and 16 of rod 7 are both mutually offset and offset relative to opening 14,
as well as arms 15′ and 16′ which are both mutually offset and off set relative to
opening 14. This is the essential feature of this invention, in that it is just because
of said feature that, when the collapsible canvas covering is collapsed, between rods
7, 7′ there is provided the available room 12 whose important function has already
been described above.
[0009] Lower arm 16 of rod 7 is connected at the lower end thereof, to arch 2 by means of
hinge 10. Upper arm 15 of the same rod 7 is fastened at the upper end thereof to sleeve
18 which is slidably mounted on vertical bar 6 fastened to arch 2′, the latter arch
being immediately adjacent to the arch on which the lower end of said bar is fastened.
Lower arm 16′ of rod 7′ is pivoted to arch 2′ at 9, and upper arm 15′ of said rod
7′ is fastened to sleeve 17 which is slidably mounted within bar 6 fastened on upper
part of arch 2 immediately close to arch 2′ whereupon there is pivoted, at 9, the
lower arm 16′ of said rod.
[0010] In Figure 4 there is shown another embodiment of the pantograph linkage element according
to this invention. According to the latter embodiment, rods 7 and 7′ are not bent
at their central area 13, but they are actually interrupted at said area. This embodiment
was obtained using a rectangular cross section metal rod whose two equal length segments
15 and 16 are welded, respectively at the lower end and at the upper end thereof,
on the side of a segment 13, substantially shorter than the first two, but of the
same material. Rod 7′ has been constructed in the same way, and both the short central
segments 13 and 13′ are provided with an opening 14 adapted to receive pivot pin 8.
In this embodiment as well there is present the basic feature of this invention,
i.e. the fact that the two arms of each rod are offset both mutually and relative
to opening 14.
[0011] In Figure 5, which shows a side elevational view of the lower part of an arch 2,
there is shown that arms 15, 16 and 15′, 16′ of the rods (which are partially broken
away for simplicity and clarity) are not straight, but are rather slightly curved,
in order to follow the curvature of arch 2. This feature is particularly useful in
that it enables the members of the pantograph linkage to be kept very close to the
arches, whereby room is gained underneath the collapsible canvas covering, and in
addition the whole structure acquires a better appearance. The room gained is particularly
important in those cases when the pantograph linkage members reach a height from 4
to 5 meters, and that is true in those cases where the dimensions of the collapsible
canvas covering are such as to allow a pitch higher than 3 meters to be used between
adjacent arches.
[0012] The embodiments described and shown herein have been reported only as exemplary cases
of this invention, and in no way they should be interpreted in a limiting sense. Further
modifications and/or additions can be made to them by those skilled in the art, without
exceeding the scope of the invention.
1. Collapsible canvas coverings for sports grounds and the like, comprising a waterproof
canvas supported by a plurality of arches capable of being taken mutually closer
or moved apart by means of connecting pantograph linkages comprising two rods centrally
pivoted to each other in a St.Andrews' cross fashion, and having the ends thereof
connected to said arches in a known fashion, characterized in that the two rods (7,
7′) forming each pantograph linkage are each comprised of two arms (15, 16 and 15′,
16′) symmetrically offset to each other relative to opening (14) for the pivot pin
connecting said rods.
2. The canvas coverings of Claim 1, characterized in that the offset between arms
(15, 16 and 15′, 16′) of the two rods (7, 7′) of each pantograph linkage is obtained
by bending each rod in the central area thereof.
3. The canvas coverings of Claim 1, characterized in that the offset of arms (15,
16 and 15′, 16′) of each rod (7, 7′) of the pantograph linkage is obtained by forming
each rod by means of two segments of metal sections having the same length of the
arms (15, 16 and 15′, 16′) of each rod, which have an end welded alongside a shorter
segment (13) of the same metal section.
4. The collapsible coverings of Claim 2 and 3, characterized in that rods (7, 7′)
of each pantograph linkage are made of a tubular metal section of a rectangular cross
section.
5. The collapsible canvas coverings according to one or more of the preceding Claims,
characterized in that rods (7, 7′)constituting each pantograph linkage are curved
according to an arc with a shape parallel to the span of the covering arches to which
they are fastened.