[0001] The present invention refers to a seaming module of the type to be used for seaming
sheet elements, in particular for assembling two sheet elements by drawing a fin of
the edge of an element up to the edge of the other element.
[0002] These workings are widely used in the field of the automotive manufacturing, in order
to seam movable portions of a body, such as doors, hatchback doors, bonnets and mudguards.
[0003] The seaming module according to the invention has been conceived in order to carry
out the known seaming method according to which an edge to be seamed, which is already
approximately folded at 90° with respect to the plane of the sheet, is partially folded
during a first step of pre-seaming, at an angle of the order of 45°, in the direction
of the other sheet; in a second step, properly of seaming, the already partially folded
edge, is completely folded, until it is applied onto the edge of the other sheet.
[0004] A seaming module according to the preamble of claim 1 is known from EP-A-0 724 922,
in which the kinematic chain which mechanically connects the rotary shaft of the source
of motion respectively to the first folding blade and to the second folding blade,
comprises cams supported by the rotary shaft and respective tracing members.
[0005] This solution is mechanically effective, but its main disadvantage lies in the relatively
high cost required for working the cams.
[0006] The object of the invention is to make a seaming module of the type set forth above,
whose kinematic chain can be made more economically, which is reliable and allows
high production rates.
[0007] According to the invention, this object is reached by a seaming module for sheets
such as claimed.
[0008] By virtue of the idea of solution claimed, it is possible to make a seaming module
in which the cyclical movements of the two pre-seaming and seaming blades are controlled
positively and with a perfect synchronization, from a common source of motion, such
as an electrical ratio-motor, by control means which comprise transmission members,
in particular gear wheels, connecting rods and levers, which do not require expensive
workings to be manufactured.
[0009] The invention will turn out to be more clear from reading the following detailed
description, which has been provided as a non-limitative example and has been made
with reference to the appended drawings which represent a preferred embodiment, and
in which:
- figure 1 is a schematic side sectional elevational view showing the seaming module
of the invention in a condition preceding the beginning of a seaming cycle,
- figure 2 is a view similar to figure 1, showing the seaming module in a condition
in which the seaming cycle is started,
- figures 3 to 5 are schematic views similar to figures 1 and 2 but in a reduced scale,
in which the seaming module is shown during successive steps of the seaming cycle,
- figure 6 is a front elevational view sectioned along line VI-VI of figure 5,
- figure 7 is an elevational view from arrow VII of figure 6,
- figures 8 and 9 are schematic views similar to figures 3 to 5, which represent the
seaming module during further steps of the seaming cycle, and
- figure 10 is a side elevational view showing the seaming module in a rest condition
in which a seaming blade thereof can undergo a setting up or final adjustment operation
before actuating the module.
[0010] With reference to the figures, a seaming module 10 according to the invention performs
the seaming of two sheet elements W1, W2 arranged on an upper horizontal supporting
surface 11 of a bed 12, which is associated or can be associated to the seaming module,
by means of a first folding blade 14, or pre-seaming blade, and of a second folding
blade 16, or seaming blade, which operate from above. Hovever, this arrangement is
not limitativa, and a seaming module according to the invention could operate on sheet
members whose attitude can be different from horizontal.
[0011] The seaming module 10 comprises a sturdy frame, indicated 18 as a whole, which is
formed besides by a base 20 and a pair of flanks 22, which enclose and support the
most of its components.
[0012] The seaming module 10 comprises control means supported by the frame 18, which are
adapted to apply to the first folding blade 14 and to the second folding blade 16
respective synchronized cyclical movements, described in the following, between their
rest and working positions.
[0013] Such control means comprise a source of common rotary motion, in the shape of an
electrical ratio-motor 24 (figures 6 and 7), and a double kinematic chain, indicated
26 as a whole.
[0014] The double kinematic chain 26 mechanically connects an output rotary shaft 28 of
the ratio-motor 24 respectively to the first folding blade 14 and to the second folding
blade 16.
[0015] In particular, the control means comprise a driving gear wheel 30 fast to the shaft
28, with which a driven gear wheel 32 meshes, which is fast to a driven shaft 34.
[0016] Preferably, the driving wheel 30 controls the driven wheel 32 according to a 1:1
ratio, so that the driven shaft 34 rotates at the same speed of the output shaft 28
of the ratio-motor 24.
[0017] A first linkage, indicated 36 as a whole, which receives the motion from the driven
shaft 34, is associated with the first folding blade 14.
[0018] A second linkage, indicated 38 as a whole, which receives the motion directly from
the output shaft 34 of the ratio-motor 24, is associated with the second folding blade
16.
[0019] The first linkage 36 comprises, in succession, a first crank 40 fast to the driven
shaft 34, a first connecting rod 42 and a first rocking lever 44 pivoted about a first
axis of oscillation A1.
[0020] An arm 46 of the lever 44 supports the first folding blade 14 through a blade holder
48, and the connecting rod 42 interconnects the first crank 40 and the other arm 50
of the lever 44.
[0021] The second linkage 38 comprises, in succession, a second crank 52 directly fast to
the output shaft 28 of the ratio-motor 24, a second connecting rod 54 whose end opposite
to the second crank 52 is articulated at 53 to a support member 53a fixed to an arm
60 of a second rocking lever 56. The support member 53 supports a movable counter
lock 55 provided with two opposite faces 55a and 55b having an arched surface. The
second folding blade 16 is articulably supported at the end of another arm of the
second rocking lever 56, indicated with the reference numeral 58 and opposite to the
arm 60.
[0022] The second rocking lever 56 is part of an assembly, indicated 62 as a whole, which
comprises an oscillating head 64 pivoted about a second axis of oscillation A2, which
is fixed and parallel to the first axis A1.
[0023] The second rocking lever 56 is also pivoted on the oscillating head 64, about a third
axis A3 which is parallel to the second axis A2 and is off from the second folding
blade 16 of an amount smaller than the distance of the second folding blade 16 from
the second axis A2.
[0024] The oscillating head 64 and the frame 18 are provided with limit stops, respectively
movable 66 and fixed 68, which can mutually engage in frontal bearing.
[0025] As it will be made more clear in the following, when the second rocking lever 56
reaches a predetermined angular position, which corresponds to the configuration of
figures 4 to 8, the movable limit stop 66, which is supported by the oscillating head
64, frontally engages the fixed limit stop 68 and prevents a further rotation of the
oscillating head 64 about the second axis A2 during its angular movement towards the
working position of the second blade 16.
[0026] Elastically yieldable means are interposed between the second rocking lever 56 and
the oscillating head 64, which, as it can be better understood in the following, are
adapted to allow the aforesaid further rotation of the lever 56, but this time about
the third axis A3, to the working position of the second blade 16, shown in figure
5, while the oscillating head 64 is kept locked owing to the aforesaid engagement
of the limit stops 66, 68.
[0027] Preferably, as shown, these elastically yieldable means consist of a sturdy compression
coil spring 70, schematically indicated by dashed lines in the figures.
[0028] A first formation 65 having an arched surface 65a concentric with the third axis
A3 and complementary to the arched surface 55b of the movable counter lock 55, is
fixed to the oscillating head 64, while a second formation 67 having an arched surface
67a, which is also concentric to the axis A3 and is complementary to the arched surface
55a of the movable counter lock 55, is connected to the frame 18, in a position facing
the oscillating head 64.
[0029] The assembly 62, to which the second rocking lever 56 belongs, comprises also a body
72 which supports the second folding blade 16 through a blade holder 74.
[0030] The support body 72 is articulated to the arm 58 of the second rocking lever 56 about
a fourth axis A4 parallel to the third axis A3.
[0031] One portion of a link rod 76, parallel to the arm 58, is articulated to the oscillating
head 64, the other portion thereof being articulated to the support body 72, respectively
about a fifth axis A5 and about a sixth axis A6, both parallel to the third axis A3
and to the fourth axis A4.
[0032] The oscillating head 64, the support body 72, the aforesaid arm 58 and the link rod
76 form therefore a four-bar linkage, indicated 78 as a whole, which is arranged in
such a manner that, when the oscillating head 64 is kept locked by the engagement
of the limit stops 66, 68, a rotation of the second rocking lever 56 about the third
axis A3 towards the working position of the second folding blade 16 causes a movement
of the second folding blade 16 which is substantially rectilinear and perpendicular
to the support surface 11 of the sheet elements W1, W2. The advantage of this arrangement
will be clarified in the following.
[0033] In figure 1, a removable pin defining the axis A4 and connecting the support body
72 to the arm 58 of the second rocking lever 56, has been indicated 80. A specific
function of the removable pin 80 will be described in the following with reference
to figure 10, in which the seat from which the pin 80 has been removed, has been indicated
80a.
[0034] It will be now referred in succession to figures 1 to 9 in order to describe a seaming
cycle.
[0035] Figure 1 corresponds to the initial condition in which the sheet elements W1, W2
to be seamed have been correctly arranged and positioned on the support surface 11
in view of the seaming.
[0036] In this figure, the sheet element W1 has an end fin L already square folded, which
is arranged on the side facing the seaming module 10.
[0037] Both the pre-seaming blade 14, or first folding blade, and the seaming blade 16,
or second folding blade, are raised and withdrawn to respective rest positions in
which they do not interfere with the laying of the sheet elements W1, W2 to be seamed
on the support surface 11, and with the removal thereof from the surface 11 after
seaming (from above, in the example of the figures).
[0038] In the figures, the direction of rotation of the shaft 28 which controls the second
linkage 38 is indicated R, the direction of rotation of the shaft 34 which controls
the first linkage 36 being opposite to R as a result of the meshing of the gear wheels
30 and 32.
[0039] As previously stated, the shaft 34 rotates with the same speed of the shaft 28, so
that the first linkage 36, associated to the first blade 14, performs a number of
cycles of movement wich is equal to that of the second linkage 38.
[0040] The first folding blade 14 has a working or press face 14a adapted to engage the
square fin L and to fold it substantially at 45°.
[0041] In a first step (which corresponds to the passage from the condition of figure 1
to that of figure 2), the first folding blade 14 moves forward with an arched movement
about the first axis A1, and its working face 14a, in its final portion of movement,
approaches the fin L along a direction substantially at 45° with respect to the support
surface 11 of the bed 12 (arrow F1, figure 2), in order to carry out the bending of
the fin L approximately at 45° with respect to the surface 11.
[0042] In the meantime, the second linkage 38 has caused the forward movement of the second
folding blade 16, as a single piece with all the assembly 62, along a portion of arched
path about the second axis A2 (arrow F2), approaching the second blade 16 to the working
position. In this step, owing to the upward thrust carried out by the connecting rod
54 on the support member 53a, and therefore on the counter lock 55, the arched surface
55b of the counter lock 55, in sliding engagement with the arched surface 65a of the
formation 65, slides along a portion of the surface 65a, causing the counter lock
55 to approach the formation 67.
[0043] In a second step (figure 3), the first folding blade 14 withdraw from the zone of
the fin L, which has been folded at 45°, in order to make room to the second folding
blade 16 which goes down towards the fin L with an active front face 16a thereof,
according to the arched path still indicated by arrow F2. In this second step, the
arched surface 55b of the counter lock 55 continues to slide along the surface 65a,
raising to the space interposed between the arched surfaces 65a and 67a which go away
to each other.
[0044] At the beginning of a third step (figure 4), the second folding blade 16, still following
the arched path about the axis A2, indicated yet by arrow F2, has reached a position
in which it perpendicularly stands above the fin L. In this condition, the movable
limit stop 66 which is supported by the oscillating head 64 abuts on the fixed limit
stop 68, so that the movement of the head 64 according to the arrow F2 cannot continue
anymore.
[0045] Owing to the thrust of second connecting rod 54, the second rocking lever 56 continues
instead its rotation in the direction of arrow F3 (figure 5), this time about the
third axis A3 which is now become fixed. This rotation causes also a further movement
of the counter lock 55 until it is carried, as a result of the sliding of its arched
surfaces 55a and 55b, respectively along the corresponding arched surfaces 67a and
65a of the formations 67 and 65, in a position in which it fully covers the space
interposed between the formations 65 and 67. In this position, the counter lock 55
effectively prevents the pressure effort carried out by the second folding blade 16
on the fin L to cause a counter-rotation of the oscillating head 64 about the axis
A2.
[0046] The movement of the fulcrum of the second rocking lever 56 from the second axis A2
to the third axis A3 corresponds to an increase of the mechanical advantage of the
lever 56, that is to an intensification of the bending force carried out by the second
blade 16 on the fin L.
[0047] The rotation according to arrow F3 is allowed by the elastic yielding of the spring
70, which is now compressed, while during the previous steps, from figure 1 to figure
4, the spring 70 substantially acted as a rigid element.
[0048] By virtue of the presence of the four-bar linkage 78, the final working movement,
that is of seaming, of the second folding blade 16, represented in the position of
figure 5, is substantially rectilinear and perpendicular to the support surface 11,
as indicated by arrow F4 in such a figure.
[0049] In this final seaming step, the second folding blade 16 acts on the fin L by its
active front face 16a fully pressing the fin L, that is folding it completely on the
edge of the sheet element W2.
[0050] The characteristics of increment of the mechanical advantage of the lever 56, caused
by the aforesaid change of fulcrum from A2 to A3, and of the rectilinear working movement
of the second folding blade 16, caused by the four-bar linkage 78, represent an advantage
with respect to the solution known from EP-A-0 724 922, in which no means of intensification
of the bending force carried out by the second blade on the fin to be seamed were
provided, and in which the second blade followed an arched path also during the working
step, with the consequence that a component of side force, detrimental to the precision
of the seaming, was applied on the fin.
[0051] After the completion of the seaming, as shown in figure 5, the second linkage 38
brings the whole assembly 62 of the second blade 16 back, in a raised position with
respect to the sheet elements W1, W2, passing through the positions shown in figures
8 and 9. In order to make possible the attainment of such a position by the assembly
62, and therefore the rotation of the oscillating head 64 about the axis A2, the counter
lock 55 is removed from the space interposed between the formations 65 and 67, by
sliding its arched surfaces 55a and 55b on the corresponding arched surfaces 67a and
65a of the formations 67 and 65, as a result of a traction carried out by the second
connecting rod 54 of the linkage 38 on the support member 53a.
[0052] In the meantime, the first linkage 36 has caused the first blade 14 to perform a
cycle of movement which has brought it back in a position corresponding to that of
figure 1, in which it is ready for a new working cycle.
[0053] With reference to figure 10, the four-bar linkage 78 arrangement allows to take advantage
of a favourable opportunity. As already pointed out above, the pin 80, which defines
the axis A4, can be removed for leaving its seat, indicated 80a, free. In this manner,
the support body 72 can be overturned about to the axis A6, in the direction of arrow
F5 of figure 10, until it reaches the position in solid lines of the same figure 10.
In this position, the active front face 16a of the seaming blade 16 is directed upwardly
and is therefore easily approachable by an operator who, by means of a tool such as
a grinder, can easy perform any correction or maintenance operation of the face 16a
of the blade 16 which is needed before actuating the seaming module 10.
1. Seaming module for sheets, comprising:
- a frame (18) to which a support surface (11) for supporting sheet elements (W1,
W2) to be seamed is associated or can be associated,
- a first folding blade (14), or pre-seaming blade, adaped to perform a first bending,
of an angle of the order of 45° with respect to the support surface (11), of a fin
(L) already square folded of one of said sheet elements (W1), said first folding blade
(14) being supported by the frame (18) so as to be able to oscillate about a first
axis (A1) and being movable between a rest position and a working position along a
path that, in proximity of the working position, is substantially parallel to the
support surface (11),
- a second folding blade (16), or seaming blade, adapted to perform a second bending
of the fin (L) already substantially folded at 45°, in such a manner that it is parallel
to the support surface (11) and superimposed to an edge of the other (W2) of said
sheet elements, said second folding blade (16) being supported by the frame (18) so
as to be able to oscillate about a second axis (A2) parallel to the first axis (A1)
and being movable between a rest position and a working position along a path that,
in proximity of the working position, is substantially perpendicular to the support
surface (11), and
- control means carried by the frame (18) for moving the first folding blade (14)
and the second folding blade (16) according to respective synchronized cyclical movements
between their rest and working positions, said control means comprising a source of
common rotary motion (24) and a kinematic chain (26) mechanically connecting a rotary
shaft (28) of the source of motion (24) respectively to the first folding blade (14)
and to the second folding blade (16),
characterized in that:
- said control means comprise a first linkage (36) associated to the first folding
blade (14) and a second linkage (38) associated to the second folding blade (16),
both the linkages receiving the motion from the rotary shaft (28) of the source of
motion (24),
- said first linkage (36) comprises a first crank (40), a first rocking lever (44)
pivoted about said first axis (A1) and an arm (46) of which carries the first folding
blade (14), and a first connecting rod (42) interconnecting the first crank (40) and
the other arm (50) of the first rocking lever (44), and
- said second linkage (38) comprises a second rocking lever (56) pivoted about said
second axis (A2) and an arm (58) of which carries the second folding blade (16), and
a second connecting rod (54) interconnecting the second crank (52) and the other arm
(60) of the second rocking lever (56).
2. Seaming module for sheets according to claim 1,
characterized in that:
- the second rocking lever (56) is part of an assembly (62) which comprises an oscillating
head (64) pivoted about said second axis (A2) and to which the second rocking lever
(56) is pivoted about a third axis (A3) parallel to the second axis (A2) and which
is off from the second folding blade (16) of an amount smaller than the distance of
the second folding blade (16) from the second axis (A2),
- the oscillating head (64) and the frame (18) are provided with respective limit
stops (66, 68) which can mutually engage in order to prevent a further rotation of
the oscillating head (64) about said second axis (A2) when the second rocking lever
(56) has reached a predetermined angular position along its angular movement towards
the working position, and
- elastically yieldable means (70) are interposed between the second rocking lever
(56) and the oscillating head (64), in order to allow a further rotation of the second
rocking lever (56) about said third axis (A3), towards the working position of the
second blade (16), while the oscillating head (64) is kept locked owing to the engagement
of the aforesaid limit stops (66, 68).
3. Seaming module for sheets according to claim 2, characterized in that a movable counter lock (55) is associated to the second rocking lever (56), which
is intended to cover a space interposed between the frame (18) and the oscillating
head (64) during said further rotation of the second rocking lever (56) about the
third axis (A3) and towards the working position of second blade (16), in order to
prevent a counter-rotation of the oscillating head (64) about the second axis (A2)
as a result of the effort of pressure carried out by the second folding blade (16)
on said fin (L).
4. Seaming module for sheets according to claim 3, characterized in that the movable counter lock (55) is supported by a support member (53a) fixed to said
other arm (60) of the second rocking lever (56), the second connecting rod (54) of
the second linkage (38) being articulated to the support member (53a).
5. Seaming module for sheets according to claim 4, characterized in that the movable counter lock (55) has two opposite faces (55a, 55b) having an arched
surface, which are adapted to slidably engage corresponding arched surfaces (67a,
65a) fast to the frame (18) and to the oscillating head (64), both of which are concentric
with said third axis (A3).
6. Seaming module for sheets according to claim 5, characterized in that the arched surfaces (67a, 65a) fast to the frame (18) and to the oscillating head
(64) are respectively formed on formations (65, 67) which are fixed to the oscillating
head (64) and to the frame (18).
7. Seaming module for sheets according to anyone of claims 2 to 6, characterized in that it comprises a body (72) for supporting the second folding blade (16), which is articulated
to a corresponding arm (58) of the second rocking lever (56) about a fourth axis (A4)
parallel to the third axis (A3), a link rod (76) parallel to such an arm (58) and
articulated at one side to the oscillating head (64) and at the other side to the
support body (72), respectively about a fifth axis (A5) and about a sixth axis (A6),
which are parallel to the third axis (A3) and to the fourth axis (A4), and in that the oscillating head (64), the support body (72), the aforesaid arm (58) and the
link rod (76) form a four-bar linkage (78) arranged in such a manner that when the
oscillating head (64) is kept locked by the engagement of the limit stop surfaces
(66, 68), a rotation of the second rocking lever (56) about the third axis (A3) towards
the working position of the second folding blade (16) causes a movement of the second
folding blade (16) substantially rectilinear and perpendicular to the support surface
(11) of the sheet elements (W1, W2).
8. Seaming module for sheets according to anyone of the preceeding claims, characterized in that the second crank (52) and a driving gear wheel (30) are fast to the aforesaid rotary
shaft (28) of the source of motion (24), and the first crank (42) is fast to a driven
shaft (34) to which a driven gear wheel (32) is also fast, which meshes with the driving
gear wheel (30).
9. Seaming module for sheets according to claim 8, characterized in that the ratio of transmission between said driving gear wheel (30) and said driven gear
wheel (32) is 1:1, thereby the first folding blade (14) performs a cycle of movement
for each cycle of movement of the second folding blade (16).
10. Seaming module for sheets according to claim 7, characterized in that the support body (72) is articulated to the correspondent arm (58) of the second
rocking lever (56) by means of a removable pin (80), in order to allow to overturn
the body (72) about an axis (A6) of articulation of the body (72) to the aforesaid
link rod (76) of the four-bar linkage (78), until the body (72) reaches a position
in which an active front face (16a) of the seaming blade (16) is directed upwardly
and is easily approachable in order to perform corrections of such an active front
face (16a) by means of a tool.