U.S. patent number 3,901,146 [Application Number 05/223,856] was granted by the patent office on 1975-08-26 for squeegee mount for independent pressure and angle adjustments.
This patent grant is currently assigned to Societe Alsacienne de Constructions Mecaniques de Mulhouse. Invention is credited to Gerard Stierlein.
United States Patent |
3,901,146 |
Stierlein |
August 26, 1975 |
Squeegee mount for independent pressure and angle adjustments
Abstract
An adjustable squeegee supporting device of a rotating screen in
a sheet material printing machine of the type wherein the squeegee
is supported by a bar, the two ends of which are connected
respectively to two exterior fixed points through two links and is
subjected to the action of position adjusting means. One of the
ends of the links is rigidly connected to the bar and the other is
pivotally mounted on an axis along the line of contact of the
screen with the material. The inclination of the links may be
adjusted through two rods connected to two simultaneously
adjustable disk-cranks. The free edge of the squeegee is applied
against the screen by means of an inflatable tube interposed
between the squeegee and its supporting bar.
Inventors: |
Stierlein; Gerard
(Mulhouse-Bourtzwiller, FR) |
Assignee: |
Societe Alsacienne de Constructions
Mecaniques de Mulhouse (Mulhouse, FR)
|
Family
ID: |
9071887 |
Appl.
No.: |
05/223,856 |
Filed: |
February 7, 1972 |
Foreign Application Priority Data
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|
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Feb 15, 1971 [FR] |
|
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71.04957 |
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Current U.S.
Class: |
101/119;
101/120 |
Current CPC
Class: |
B41F
15/44 (20130101) |
Current International
Class: |
B41F
15/14 (20060101); B41F 15/44 (20060101); B41f
015/42 () |
Field of
Search: |
;101/120,119,116,129,123,124,114,115,157,169 ;15/256.51 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Burr; Edgar S.
Assistant Examiner: Suter; R. E.
Attorney, Agent or Firm: Cantor & Kraft
Claims
What is claimed is:
1. A device for adjustably supporting a flexible squeegee within a
rotating horizontal cylindrical screen of a sheet material printing
machine, said screen engaging the material to be printed along a
nip, said squeegee having a securing edge and a free operative
edge, said device comprising: a supporting bar extending axially
through said cylindrical screen and longer than the axial length of
said screen, said supporting bar having end portions, said securing
edge of said squeegee being secured to said supporting bar, fixed
support means, two links located at either end of said screen, the
end portions of said supporting bar being respectively rigidly
secured to one end of one of said links, the other end of each of
said links being pivotally mounted to said fixed support means on
an axis which is in alignment with said nip, supporting bar
adjusting means connected to said fixed support means for adjusting
the angular position of said two links relative to the radial plane
containing said nip, said operative edge of said squeegee always
being located substantially along said nip, and means for biasing
said squeegee to cause said operative edge of said squeegee to
press the inner surface of said screen at said nip with a
predetermined pressure.
2. A device as defined in claim 1, wherein said supporting bar
adjusting means comprises: two crank-disks each having a crank-pin,
two further links, each further link having one end pivotally
connected to the crank-pin of one of said crank-disks and the other
end pivotally connected to one end of said supporting bar, a
horizontal shaft parallel with said squeegee rotatably mounted on
said fixed support means, said crank-disks being rigidly secured to
said pivoting shaft, and means for adjusting the angular position
of said shaft.
3. The device as defined in claim 1, wherein said biasing means
comprises an inflatable air tube extending lengthwise between said
supporting bar and said squeegee, said inflatable air tube engaging
said supporting bar and a longitudinal area of said squeegee
located between said securing edge and said operative edge of said
squeegee.
Description
BACKGROUND OF THE INVENTION
This invention relates to adjustable supporting devices for a
squeegee inside a rotating screen in a machine for printing sheet
materials such as, for example, cloth.
The invention concerns more particularly the devices of the type in
which the flexible squeegee is supported by a bar two ends of which
are connected, respectively, to two fixed points exterior to the
screen through two links, and is subjected to the action of
position adjusting means, for example such as those described in
French Pat. publication No. 2006 887.
PRIOR TECHNIQUES
In a known embodiment of this type, the two ends of the bar through
which the squeegee is supported are connected to the moving parts
of two vertical screw jacks and they are rigidly connected to one
end of the two links, the other end of which may horizontally slide
in guiding members disposed substantially at the same level as the
screen axis. This arrangement has the disadvantage of providing
only a single adjusting means, i.e., a height adjustment of the two
screw jacks, so that, for each position of said screw jacks there
is not only a definite angle of the edge portion of the squeegee
against the screen, but also a definite pressure which cannot be
varied without modifying the inclination angle of said squeegee.
Moreover, the position of the operative edge of the squeegee
against the screen cannot be accurately adjusted as desired, said
position resulting from the inherent bending of the flexible
squeegee in response to the position given to its supporting bar.
In other words, the only adjusting means available does not permit
individually adjusting the pressure of the squeegee operative edge,
the angle of the squeegee edge portion with the screen, and the
accurate position of the squeegee edge.
In a further known embodiment of the aforesaid type, each end of
the bar which supports the squeegee is no longer rigidly connected
to one end of the link, but is rigidly connected to one end of the
moving part of the corresponding vertical screw jack, the other end
of which, i.e. its upper end, is pivotally mounted about a
horizontal axis, while each end of said bar is pivotally mounted on
one end of the corresponding link, the other end of which is also
pivotally mounted on the exterior fixed point, the length of said
link being adjustable. Two adjusting means are thus available, i.e.
a height adjustment through vertical screw jacks and a horizontal
adjustment through the length adjustable link. However, the
squeegee is widely distorted and thus assumes an inherent bending
resulting from the combination of said two above noted adjustments.
Due to the fact that the two adjustments react upon each other, it
is very difficult to impart to the squeegee a predetermined angle
at the same time as a predetermined pressure, independently from
each other and, moreover, to accurately position the operative edge
of the squeegee, since in any case, three parameters have to be
determined whereas only two adjusting means are available.
OBJECT AND SUMMARY OF THE INVENTION
The present invention has for its object the provision of a
reliable device of simple construction which, however, permits an
individual accurate adjustment of the squeegee pressure against the
screen and of the angle of the operative edge thereof with the
screen surface, all by distinct and easily operable means.
For this purpose, the device is designed in such a way that the
operative edge of the squeegee is always automatically located
substantially along the desired line of contact of the screen with
the material, i.e. always the same, at the location where printing
must take place, while through two very simple means, not reacting
upon each other, the angular position of the squeegee and its
pressure against the screen may be individually adjusted.
Therefore, according to the present invention, the two ends of the
squeegee supporting are rigidly connected to one end of each link,
of fixed length, the other end of which is pivotally mounted about
an axis which coincides with the horizontal plane along which said
screen is intended to engage with the sheet material to be printed,
the operative edge of the squeegee being disposed adjacent the line
of contact of the screen and the material, the adjusting means for
the position of the bar consisting of simultaneous adjusting means
for the angular position of the two links relative to the
horizontal plane of the screen containing said line of contact,
said device further comprising means for resiliently flexing the
squeegee so that its operative edge is in engagement with the inner
surface of the cylindrical screen coinciding with said line of
contact.
With such a device, there is no need to care for the position of
the squeegee edge, since said edge is always at the right place.
The inclination angle of the squeegee may be conveniently adjusted
by giving to the links a corresponding inclination and this without
any interference with the squeegee pressure, which is adjusted
through independent adjusting means.
According to a preferred embodiment of the invention, the adjusting
means for the squeegee pressure against the screen is in the form
of an inflatable air tube arranged so as to be connected to an air
supply at a suitable pressure, and interposed between the squeegee
and its supporting bar.
The invention will be more clearly understood from the following
description with reference to the accompanying drawings, which
represent, by way of example only, one embodiment of a squeegee
supporting device according to the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a side view of the device according to the invention,
FIG. 2 is a top view of the device of FIG. 1,
FIGS. 3 and 4 show on an enlarged scale the maximum and minimum
limit inclination positions of the squeegee relative to the screen,
with the edge of the squeegee being not applied against said
screen, and
FIG. 5 shows the squeegee in operative position, with the same
inclination as in FIG. 4.
DETAILED DESCRIPTION OF THE INVENTION
The device illustrated in FIGS. 1 and 2 is intended for adjustably
supporting a squeegee 1 (see FIG. 3) inside a rotating cylindrical
screen 2 for printing on sheet materials such as for example a
cloth 3. The location of the rotating screen 2 is immovable with
respect to the machine frame 21.
The squeegee 1 is secured, for example, through a clamp 5 to a
portion of a rectangular cross-section bar 6 disposed inside the
screen and the ends of which comprise two sockets 7, 8 secured to a
round bar 9 extending axially through the screen and protruding
outwardly of said screen at each end thereof.
The two ends of bar 9 are supported in the same manner so that only
the supporting means for one of said ends will be described, with
the supporting means for the other end of said bar being designated
by the same reference numerals bearing the suffix A.
The two ends of bar 9 are thus supported by the upper ends of two
links 12, 12A. The lower end of link 12 is pivotally mounted about
an axis 13 on the upper portion of a leg 14, the lower end of which
is carried by a plate 15 secured in turn in a horizontal arm 16 of
a bracket 17 integral with a tube 18 which is secured to two
supports 19, 19A, fixed on frame 21 of the printing machine.
The reference numeral 22 indicates for illustration purposes, a
supporting roller for the sheet 3 to be printed on. The pivoting
axis 13 for the link 12 on the leg 14 is situated substantially in
alignment with the nip of roller 22 with the cylindrical screen 2.
The accurate positioning of said axis is facilitated by the fact
that leg 14 is vertically adjustable through means schematically
illustrated in the drawings in the form of a bolt 24 which extends
through a hole in the leg 14 and a vertical slot 25 in the plate
15, with the latter being also horizontally adjustable through
similar means, for example, in the form of a bolt 26 which extends
through a hole in said plate and a horizontal slot 27 in the arm
16.
In FIG. 1, the direction of link 12 is the same as that of the
rectangular bar 6 so that the latter is not visible on said
figure.
The inclination of links 12 and 12 A may be adjusted by means of
two also identical devices, one of which comprises a rod 31, one
end of which carries two bent fingers 32, 33 which grip the
corresponding end of the round bar 9 and the other end of which is
pivotally mounted on a crank pin 34 of a crank disk 35 rigidly
secured to one end of a transverse shaft 36 rotatably mounted
within tube 18. The other end of shaft 36 carries a crank-disk 35A
having a crank pin 34A for driving a rod 31A connected to the other
end of the round bar 9. The angular position of the crank-disk 35
may be conveniently adjusted through a worm 41 rotatably vertically
mounted in bracket 17 and meshing with a tangential toothed wheel
consisting of a toothing 42, cut for example in the edge of
crank-disk 35. The upper end of the worm shaft carries a knurled
control knob 43 through actuation of which, the worm 41 may be
selectively rotated in either direction, so as to cause rotation of
the two crank-disks 35 and 35A in a corresponding direction, thus
modifying the inclination of links 12 and 12A and thereafter that
of squeegee supporting bar 6.
The above described construction is so arranged that, when the
squeegee 1 is disengaged from the cylindrical screen 2, whatever
may be the inclination of links 12 and 12A and therefore that of
supporting bar 6, the operative edge of the squeegee 1 is always
substantially along the nip of cylindrical screen 2 with the
pressure roller 22, i.e. the line designated A in FIGS. 3 to 5.
FIG. 3 shows the squeegee in one of its limit angular positions in
which it defines with the inner surface of screen 2 a maximum angle
B, while in FIG. 4, said squeegee has reached its other limit
angular position in which it defines with the inner surface of
screen 2 a minimum angle C. In FIGS. 1 and 2, the squeegee forms an
angle of intermediate value between that of angles B and C of FIGS.
3 and 4, respectively.
The squeegee 1 which is a flexible strip secured only along its
upper edge, may be applied at the desired pressure by its opposite
edge against the inner surface of the screen by any suitable means
which consists, in the embodiment illustrated, of an air tube 51
housed in a longitudinal groove 52 formed in the side of the
rectangular bar 6 facing the squeegee. When no compressed air is
supplied to tube 51, the squeegee assumes a natural planar
configuration due to its inherent resiliency, whereas when air
under a suitable pressure is supplied to tube 51, a deformation of
the portion of the squeegee which is not squeezed between the clamp
5 and bar 6 is obtained, so that the free edge of said squeegee
will bear against the inner surface of cylindrical screen 2, as
shown in FIG. 5. The pressure of the squeegee may be adjusted as
desired by varying the value of air pressure discharged into tube
51 through a hose 53 (FIG. 2).
Therefore, the adjustment of the inclination of the squeegee by
means of the knurled control knob 43 and the adjustment of the
pressure of said squeegee against the screen by means of compressed
air directed into air tube 51 are completely independent from each
other, which permits to impart to said two adjustments optimum
individual values. Whatever the selected adjustments may be, there
is no need to care for the position of the squeegee edge since the
latter is always substantially adjacent the nip A due to the
structure of the device, with the squeegee support pivoting about
axis 13 which is precisely situated in alignment with nip A.
While only one embodiment of the invention has been shown and
described it is to be understood that modifications can be made
without departing from the scope of the appended claims.
The squeegee strip may be made of an elastomer, particularly of a
plastic material, and preferably polyurethane; its Shore A hardness
is preferably between about 70 and 92 and its thickness is in the
range of 1.5 to 5 % of the free width between its free edge and the
edge of clamp 5.
* * * * *