The present invention relates to a variable-capacity product
transit store of the type comprising two parallel conveyor chains, from which are
suspended a number of supporting members or so-called "gondolas".
In stores of this sort, products are transferred in ranks,
i.e. in horizontal lines, from an input to an output in "gondolas", each of which
comprises one or more parallel shelves, and is hinged at the top to two conveyor
chains. The conveyor chains are located on opposite sides of the "gondolas", are
powered, wind about a number of sprockets, and extend along an annular path comprising
a forward branch and a return branch.
The forward and return branches have bends, i.e. comprise
a number of up and down portions between top and bottom end points defined by the
sprockets, and have respective lengths that can be varied by equal opposite amounts,
by lifting or lowering some of the sprockets, to vary the capacity of the store
as a function of product outflow requirements.
In known solutions, on reaching the output, the lines of
products are unloaded off the respective shelves by means of a vertically fixed
push member moved horizontally by an actuator. When the actuator is working, the
conveyor chains are stopped in such a position as to keep the push member, the line
of products for unloading, and the output aligned horizontally, and for this reason
In known solutions of the above type, when travelling along
the top and bottom end points, the "gondolas" tend to rock about their hinge axes
with respect to the two chains, on account of the centrifugal forces acting on the
"gondolas" along the curved top and bottom portions of the path, and repeated stopping
and starting of the step-operated conveyor chains.
As a result, the "gondolas" clash and may even become entangled
with one another if a sufficiently ample radius of curvature is not provided along
the curved portions of the path and/or if the "gondolas" are not spaced sufficiently
far apart. Moreover, along the forward branch, the products tend to slip on and
even fall off the shelves.
It is an object of the present invention to provide a variable-capacity
product transit store designed to provide a straightforward, low-cost solution to
the above drawbacks, and which is preferably compact and efficient.
According to the present invention, there is provided a
variable-capacity product transit store comprising:
- an input and at least one output for products;
- two parallel, synchronously operated conveyor chains or belts;
- a number of supporting members, each comprising at least one respective shelf
for supporting said products, and which are interposed between said conveyor chains
or belts, are hinged at the top to said two conveyor chains or belts about respective
horizontal axes to keep said shelves suspended, and are equally spaced along an
annular path comprising a forward branch and a return branch between said input
and said output; said forward branch and said return branch comprising:
the lengths of said forward branch and said return branch being variable by respective
equal opposite amounts;
- a) vertical up portions;
- b) vertical down portions;
- c) curved portions connecting said vertical portions and defining top and bottom
end points of said path;
and the store being characterized by comprising retaining means for preventing rotation
of said supporting members about said horizontal axes; said retaining means comprising
movable members, which cooperate in contact with reference portions of said supporting
members to accompany the movement of said supporting members along at least part
of said top and bottom end points.
A non-limiting embodiment of the invention will be described
by way of example with reference to the accompanying drawings, in which:
- Figure 1 shows a schematic front view of a preferred embodiment of the variable-capacity
product transit store according to the present invention;
- Figure 2 shows a larger-scale view in perspective of a component part of the
- Figure 3 is similar to Figure 1, and shows a larger-scale detail of the store
according to the present invention;
- Figure 4 shows a view in perspective, with parts removed for clarity, of the
Figure 3 detail.
Number 1 in Figure 1 indicates a variable-capacity store
defining a storage unit forming part of a line 2 for transferring products 3 arranged,
for example, in ranks, i.e. in horizontal lines perpendicular to the transfer direction.
Store 1 comprises an input 5; an output 6; and two parallel conveyor chains 7 (only
one shown) supporting a number of supporting members, or so-called "gondolas", 8
interposed between chains 7 and equally spaced along an annular path 9.
With reference to Figure 2, each member 8 comprises a number
of, e.g. four or six, parallel shelves 10, onto which the incoming products 3 at
input 5 are loaded in a manner not described in detail; and two vertical sidewalls
12, which are fitted in fixed positions to the sides of shelves 10 in a manner not
described in detail, and are hinged at their top ends 13 to chains 7 about a horizontal
axis 14 to keep shelves 10 suspended. Two cylindrical positioning appendixes 16
project from the two sidewalls 12 of each "gondola" 8 in opposite directions along
an axis 17 parallel to and eccentric with respect to relative axis 14.
With reference to Figure 1, chains 7 extend about sprockets
20 (shown schematically) to define path 9, and are operated synchronously in known
manner not shown. Path 9 comprises a forward branch 21 from input 5 to output 6,
along which shelves 10 are loaded with products 3; and a return branch 22 from output
6 to input 5, along which shelves 10 are empty. Some of the sprockets, indicated
20a, are located at the bottom of store 1, and have fixed axes of rotation 23a;
some, indicated 20b, are located at the top end of store 1, and have fixed axes
of rotation 23b; and some, indicated 20c, are located in between, and have axes
of rotation 23c which are movable vertically to vary the lengths of branches 21
and 22 by respective equal opposite amounts. More specifically, sprockets 20c are
fitted to a plate 24, which is moved vertically, by a motor not shown, with respect
to a frame of store 1.
Branches 21 and 22 comprise vertical up portions 25; vertical
down portions 26; and curved portions 27, 28, which connect portions 25, 26 and
define the top and bottom end points, respectively, of path 9 at the various sprockets
With reference to Figures 3 and 4 (which show only one
sidewall 12 of each "gondola" 8), store 1 comprises a retaining assembly 30 associated
with at least part of portions 27, 28 to prevent or reduce rotation of "gondolas"
8 about respective axes 14 close to the top and bottom end points. Assembly 30 comprises
a device 31 for the top end points, and a different device 32 for the bottom end
points. With reference to sprocket 20b in Figures 3 and 4, device 31 comprises a
number of retaining seats 33 having a substantially semicircular bottom surface
complementary to the lateral profile of appendixes 16. Seats 33 are located along
a circular trajectory 34 comprising a top accompanying portion 35 parallel to portion
27 : the vertical distance between portions 35 and 27 equals the distance between
axis 17 and axis 14 of each "gondola" 8. Seats 33 are formed in fixed positions
on the periphery of a disk 36, with the same spacing as that of "gondolas" 8, and
with their concavities facing radially outwards. Disk 36 rotates about a respective
axis 37 parallel to and fixed with respect to axis 23b, is parallel to sprocket
20b, is interposed axially between sprocket 20b and sidewalls 12, and rotates to
move seats 33 synchronously with chains 7. More specifically, disk 36 is driven
by rotation of sprocket 20b via two belt or chain drives 39, 40 arranged in series
in parallel planes, and both having a velocity ratio of one.
With reference to sprocket 20c in Figures 3 and 4, device
32 also comprises retaining seats 33, but which are defined by respective cylindrical
half-shells 43. Half-shells 43 are fitted to a chain 46, with the same spacing as
that of "gondolas" 8, project from the chain in a direction parallel to axis 23c,
and are fed by chain 46 along an undulating trajectory 44 comprising a top accompanying
portion 45 parallel to portion 28 : the vertical distance between portions 45 and
28 equals the distance between axis 17 and axis 14 of each "gondola" 8.
Chain 46 runs partly inside a guide groove 47 formed in
a plate 48 fixed with respect to axis 23c and coplanar with sprocket 20c, and is
driven by rotation of sprocket 20c via a belt or chain drive 49 with a velocity
ratio such as to move seats 33 at the same linear speed as chains 7.
At the ends of portions 25, 26, i.e. as "gondolas" 8 approach
and withdraw from portions 27, 28, appendixes 16 are automatically eased in and
out of seats 33. Trajectories 34, 44 approach and withdraw from portions 25, 26
along respective outwardly convex portions 51, 52, i.e. projecting towards path
9, to assist engagement and release of appendixes 16. At the ends of portions 27,
28, seats 33 define lateral stops to prevent "gondolas" 8 from oscillating in at
least one rotation direction about axes 14 (to limit oscillation in the opposite
rotation direction, a vertical stop wall, fixed with respect to axes 23, may be
provided). Along the intermediate portion of portions 27, 28, the edge of each seat
33 is shaped to enclose the bottom part of appendix 16 and retain it in both rotation
As will be clear from the foregoing description, assembly
30 provides for eliminating oscillation of "gondolas" 8 at the top and bottom end
points, by cooperating in contact with appendixes 16 to accompany the movement of
"gondolas" 8 along at least part of portions 27, 28. So designed, store 1 is compact,
by allowing close spacing of "gondolas" 8 and small radii of curvature of sprockets
20, and not needing an excessive amount of space for assembly 30, and is also efficient,
by virtue of cylindrical appendixes being safely engaged and released automatically
by semicylindrical seats.
Clearly, changes may be made to store 1 as described herein
without, however, departing from the scope of the present invention.
In particular, appropriately stiff belts may be used instead
of chains 46, 7; and/or each "gondola" 8 may have a different number of shelves
10; and/or appendixes 16 and assembly 30 may be provided for only one of the two
sidewalls 12 of "gondolas" 8.
Moreover, the positioning function of appendix 16 may be
performed by a portion shaped and/or located differently; and/or assembly 30 may
comprise a device similar to device 32 for the top end points as well.