Note: Descriptions are shown in the official language in which they were submitted.
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LABELING APPARATUS
DESCRIPTION
This invention relates to a labeling apparatus for dispensing and applying
self-adhesive labels arranged on a carrier web adapted to be fed step-by-step,
with
a lever mounted for pivotal movement on a housing for driving a feeding mecha-
nism for the carrier web, said feeding mechanism including a transport slide
with a
transport pawl and a table, so that on each pivoting cycle of the lever the
carrier
web is adapted to be held clamped between a clamping member of the transport
pawl and the table for entrainment by the transport slide.
Labeling apparatus of this type are known as hand-held labelers in a wide
variety of designs. They are used for price marking in retail stores, in
particular in
supermarkets and self-service establishments.
A labeling apparatus of the type initially referred to is known from DE 43 09
441 Al. This known labeler is a tongs-type hand-held labeling apparatus in
which
the labels are paid out of a label supply roll one by one, printed by a print
mecha-
nism and subsequently fed to a dispensing lip where each individual label is
delami-
nated from the carrier web and dispensed. The carrier web is moved through the
labeling apparatus by the feeding mechanism, with the feeding mechanism and
the
print mechanism for printing on the label being driven by the pivotally
mounted
lever. This lever is arranged opposite a handle rigidly mounted on the
housing.
Using a pivotal motion of the lever in opposition to the force of a spring,
the print
mechanism is moved against a platen in order to effect printing on a label
that rests
on the platen. As the lever is caused to swing back by the spring force, the
carrier
web is held clamped between the clamping member of the transport pawl and the
table of the transport slide and advanced by the transport slide through a
distance
corresponding to the label spacing, in which process the printed label is
delami-
nated from the carrier web at the dispensing lip, being subsequently applied
and
rolled onto the item to be labeled by the on-press and rolling action of an
applicator
roll.
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In all known labelers in which the feeding mechanism includes such a trans-
port slide with a transport pawl provided on a clamping member, the clamping
member is a critical part. Conventionally, this clamping member is comprised
of a
small pad coated with corundum on the side making contact with the carrier
web.
In the simplest case the clamping member is a piece of corundum paper or
corundum tape as used in grinding applications. To make sure that each label
held
on the carrier web can be moved into an accurately defined position underneath
the
print mechanism, it is important for the clamping member to establish a
contact as
defined as possible with the carrier web so that with each pivoting cycle of
the lever
the carrier web is advanced by precisely one label spacing. This is of
particular
importance with preprinted labels so that the additional print produced in the
labeler
is precisely within the boundaries of, and not on, the preprinted section. An
un-
defined advance however not only has the disadvantage that the preprinted
section
is printed over when printing on the label but also that too much of an
advance, for
example, causes the label to leave the dispensing lip before being applied to
an
object. The label becomes a "flyer" and cannot be properly rolled onto the
object.
Furthermore it is important for the clamping member to have a maximum possible
service life to enable the labeler to be also used as long as possible before
needing
repair or maintenance. Proper operation of the labeler requires the clamping
mem-
ber to clamp the carrier web reliably between it and the table to prevent any
relative
movement occurring between the carrier web and the clamping member during the
transport slide's feeding movement. Experience has shown that the clamping
member equipped with a corundum pad is unable to meet the afprementioned re-
quirements in respect of service life, reliability and accuracy. When the
corundum
pad is entrained by the transport slide, it drags along the carrier web which
is made
of paper. As a result, the corundum pad may become soiled by abraded paper and
lose its grip, whereby its reliability and accuracy regarding the carrier web
advance
are impaired. In addition, the corundum pad has a relatively undefined contact
zone because it contacts the carrier web only where corundum particles
protrude a
sufficient amount. Abraded paper between the corundum particles results in a
still
more undefined contact zone. Furthermore it frequently shows to be a
disadvantage that the use of a corundum pad as clamping member does not allow
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the advancing stroke of the carrier web to be adjusted when labels with a
different
adhesive are to be processed by the hand-held labeler. For example, labels
used in
a deep-freeze environment are provided with an adhesive different from labels
used
at room temperature, hence requiring a different feed setting.
It is an object of the present invention to improve service life, reliability
and
accuracy of the label feed in a labeling apparatus of the type initially
referred to.
According to the present invention this object is accomplished with a labeling
apparatus for dispensing and applying self-adhesive labels arranged on a
carrier
web adapted to be fed step-by-step, with a lever mounted for pivotal movement
on
a housing for driving a feeding mechanism for the carrier web, said feeding
mechanism including a transport slide with a transport pawl and a table, so
that on
each pivoting cycle of the lever the carrier web is adapted to be held clamped
between a clamping member of the transport pawl and the table for entrainment
by
the transport slide, characterized in that the clamping member of the
transport pawl
is constructed in a cutting-edge-type configuration such as to enable line
contact to
be established between the clamping member and the carrier web in a direction
transverse to the feed direction of the carrier web, said clamping member
comprising a plurality of cutting edges arranged closely adjacent each other
in the
feed direction and wherein a relative distance of said cutting edges to the
carrier
web progressively increases in a feed direction of the carrier web .
Preferably, the clamping member is comprised of several blades and the
blades protrude from the transport pawl on the side of the transport pawl
facing the
carrier web by equal amounts, and the blades are mounted on the transport pawl
in
such a manner that in the clamping position they are inclined to the carrier
web
relative to a perpendicular.
Because in the labeling apparatus of the present invention the clamping
member of the transport pawl is constructed in a cutting-edge-type
configuration
enabling line contact to be established, between the clamping member and the
carrier web in a direction transverse to the feed direction of the carrier
web, any
soiling of the clamping member liable to impair its service life, reliability
and
accuracy is precluded. The line contact obtained by the cutting-edge-type
configuration of the clamping member enables an accurately defined contact
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. y.
between the clamping member and the carrier web whereby it is ensured that
with
each pivoting cycle of the lever the transport slide of the feeding mechanism
advances the carrier web by precisely one label spacing and the label to be
printed
and dispensed is invariably moved to precisely the same position. The cutting-
edge-type configuration of the clamping member of the invention affords the
added
advantage of enabling any excess of advance to be avoided, so that no "flyers"
are
produced which leave the dispensing lip prematurely. In addition, the cutting-
edge-
type clamping member ensures a defined, pre-adjustable advancing stroke
regardless of the adhesive used on the labels.
When in one aspect of the labeling apparatus of the invention the clamping
member includes several cutting edges arranged adjacent to each other in the
feed
direction, multiple line contact can be established between the clamping
member
and the carrier web whereby reliability and accuracy of label feed can be
further
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enhanced.
When in another aspect of the (abeiing apparatus of the invention the cutting
edges are arranged at a progressively increasing distance to the carrier web
in the
feed direction, a swiveling motion of the transport pawl up to its final
clamping posi-
tion causes the individual cutting edges to make contact with the carrier web
successively, thereby ensuring reliable and accurate feeding of the labels
without
the cutting edges cutting into the carrier web. Since no cuts are made, the
clamp-
ing member cannot become soiled either.
When in still another aspect of the labeling apparatus of the invention the
clamping member is comprised of several blades, the transport pawl can be
equipped with the clamping member in a particularly simple and convenient way,
with the number of line contacts between the clamping member and the carrier
web
being selectable by the number of blades.
When in yet another aspect of the labeling apparatus of the invention the
blades are made of metal, a particularly long useful life of the clamping
member
can be ensured.
When in another aspect of the labeling apparatus of the invention the blades
protrude from the transport pawl on the side of the transport pawl facing the
carrier
web by equal amounts and when the blades are mounted on the transport pawl in
such a manner that in the clamping position they are inclined to the carrier
web
relative to a perpendicular, not only is the configuration described further
above
enabled in simple manner in which the blades' distance from the carrier web in-
creases progressively in the feed direction, but also an increasingly stronger
fric-
tional-engagement contact between the clamping member and the carrier web is
ensured when the carrier web is entrained by the transport slide due to the
pivota-
bility of the transport pawl, whereby reliability and accuracy of the feed are
further
enhanced.
Embodiments of the present invention will be described in more detail in the
following with reference to the Figures of the accompanying drawing. In the
drawing,
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FIG. I is a detailed bottom view of a transport slide of a carrier web feeding
mechanism of a labeling apparatus of the invention;
FIG. 2 is a sectional view of the transport slide taken along the line 2-2 of
FIG. 1;
FIG. 3 is a perspective view of the transport slide of FIG. 1 with the flap in
open position;
FIG. 4 is a detail view of a transport pawl of the transport slide of FIG. 1;
FIG. 5 is a vertical sectional view of the transport pawl of FIG. 4;
FIG. 6 is a vertical sectional view of a hand-held labeling apparatus known in
the art; and
FIGS. 7a - 7f are schematic views of the transport slide of the labeling appa-
ratus of FIG. 6 and of the carrier web to explain the mode of operation of the
feed-
ing mechanism. ,
The labeling apparatus shown in FIG. 6 is constructed in the same way as a
labeling apparatus of the invention, apart from the construction of a feeding
mecha-
nism 19. Therefore, to,avoid repetitions only a transport slide 40 and as
detail its
transport pawl which are part of the feeding mechanism 19 of the labeling
appara-
tus of the invention are illustrated in FIGS. 1 to 5. Before describing FIGS.
1 to 5 in
more detail, the mode of operation of the known labeling apparatus will be de-
scribed with reference to FIGS. 6 and 7.
The labeling apparatus shown in FIG. 6 has a housing 11 on which a handle
12 is integrally formed. Provided on the housing upper side is a compartment
13
for accommodating a supply reel 14 for a carrier web 15 to which self-adhesive
labels 16 are adhered. The carrier web 15 is routed in the labeling apparatus
from
the supply reel 14 in the compartment 13 to bottom left in the representation
of FIG.
6 via a projection 17 on the housing forwardly to a dispensing lip 18 where
the
carrier web 15 is deflected to be routed through a feeding mechanism generally
designated as 19 to the rearward end of the housing 11. Mounted in the housing
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11 for rotation about an axis 20 ahead of the dispensing lip 18 is an
applicator roll
with which a label 16' peeled from the carrier web 15 at the dispensing lip 18
and hence in the position ready for application can be adhered to an object by
a
rolling motion of the applicator roll 10.
Provided underneath the handle 12 is a lever 22 mounted on the housing 11
for pivotal motion about an axis 23. Seated between the handle 12 and the
lever
22 is a spring 24 indicated schematically in FIG. 6 and trying to urge the
lever 22
into the position of rest shown in FIG. 6. In the housing 11 is a print
mechanism
lever 25 which is likewise pivotal about the axis 23. The print mechanism
lever 25
supports a print mechanism 26 enabling printing of a self-adhesive label 16
posi-
tioned on a platen 27. Seated between an arm 28 of the lever 22 and the print
mechanism lever 25 is a spring 29 which serves to transmit a movement of the
lever 22 directed against the handle 12 to the print mechanism lever 25. In
the
position of rest shown in FIG. 6 the print mechanism lever 25 is held in a
raised
position by the lever 22.
For a brief description of an operating cycle of the labeling apparatus illus-
trated in FIG. 6 it is assumed that no self-adhesive label 16' is as yet in
the dis-
pensing position underneath the applicator roll 10. To initiate an operating
cycle,
the lever 22 is pulled against the handle 12 as a result of which the print
mechanism lever 25 is pivoted, due to the action of the arm 28 and the spring
29, in
anticlockwise direction about the axis 23, causing the print mechanism 26 to
be
lowered down onto the platen 27. When striking the platen 27, the print
mechanism
26 produces a print on the self-adhesive label 16 positioned on the platen 27
at this
particular instant. Via a lever 30 likewise mounted for pivotal motion on the
housing
11 but driven by the print mechanism lever 25, the feeding mechanism 19 has
been
moved at the same time from the position illustrated in FIG. 6 in the
direction of the
platen 27 longitudinally of the carrier web 15. When the lever 22 is released,
the
spring 24 operates to return the lever 22 to the initial position illustrated
in FIG. 6,
with the lever 22 pivoting the print mechanism lever 25 clockwise about the
axis 23.
At the same time, also the feeding mechanism 19 is returned to its initial
position
shown in FIG. 6. As this movement occurs, it is however in frictional
engagement
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with the carrier web 15, hence causing the carrier web to be pulled about the
dis-
pensing lip 18 by a distance corresponding to the width of a self-adhesive
label. As
this occurs, a self-adhesive label 16 is delaminated from the carrier web 15
at the
dispensing lip 18, reaching the position of the self-adhesive label 16'
underneath
the applicator roll 10. The self-adhesive label 16' is then ready to be
adhered to an
object by a rolling motion of the applicator roll 10.
The feeding mechanism 19 includes a transport slide 40 mounted for dis-
placement in the housing 11 on the underside thereof, said feeding mechanism
being described here in detail with reference to FIG. 6 only to the extent
necessary
for the understanding of the invention. For better clarity reference is also
made to
FIG. 7a. The transport slide 40 has a housing 42 out of which a flap 44
carrying the
table 45 can be swung out in downward direction. Above the flap 44 a transport
pawl 46 is mounted on the housing 42 for pivotal movement about an axis 48. A
helical spring not visible in FIGS. 6 and 7a has its ends take support upon
the
housing 42 and, respectively, the transport pawl 46 and biases the transport
pawl
46 in clockwise direction about the axis 48, thus urging it in the direction
of the table
45. 'At its end adjacent to the flap 44, the transport pawl 46 has two skids
50 ena-
bling the transport pawl 46 to take support upon adjacent longitudinal sides
of the
carrier web 15. The arrangement of the transport pawl 46 on the transport
slide 40
is selected such that when the transport slide 40 moves to the left in FIG. 6
the
transport pawl 46 is in a raised position, whilst during a movement of the
transport
slide to the right in FIG. 6 the transport pawl 46 can be lowered in order to
hold the
carrier web 15 clamped between a clamping member 52 and the table 45 formed
on the flap 44, hence enabling the transport slide 40 to entrain the carrier
web to
the right in FIG. 6, as will be described in the following in greater detail
with
reference to FIGS. 7a - 7f.
In FIGS. 7a to 7f the individual labels 16 on the carrier web 15 are numbered
consecutively from 1 to 5, with label no. 1 and label no. 3 being shaded to
show the
different relative positions of the transport slide 40 and the carrier web 15
in greater
detail. The initial position of the transport slide 40 shown in FIG. 6 is
shown also in
FIG. 7a. The carrier web 15 has wave-shaped longitudinal edges and carries
labels
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referred to as wave-edge labels. The labels involved here are only imaginary
be-
cause the carrier web 15 passing through the transport slide 40 is empty. The
labels were previously removed from the carrier web 15 at the dispensing lip
15.
The arrangement is selected such that each label 16 has two wave crests lying
opposite each other and combines with its two adjacent labels 16 to form a
wave
trough. Furthermore, the arrangement is such that in the initial position of
FIG. 7a
the transport pawl 46 rests with its two skids 50 on the two wave crests of
the
carrier web 15 corresponding to the crests of the imaginary label no. 2.
Proceeding
from the initial position of FIG. 7a, the transport slide 40 is moved to the
left as indi-
cated by an arrow pointing to the left. As this occurs, the clamping member 52
is
lifted clear of the carrier web 15 so that the carrier web 15 is not entrained
by the
transport slide 40. When the transport slide 40 moves to the left by a
distance cor-
responding to half the width of a label, the skids 50 according to the
representation
of FIG. 7b reach two adjacent wave troughs on the carrier web 15 between the
imaginary labels no. 2 and no. 3. As a result, the clamping member 52 moves
downwards, urging the carrier web 15 against the table 45. With the transport
slide
40 now continuing its movement to the left through a distance amounting to
half the
width of a label, according to FIG. 7c the skids 50 reach the two wave crests
of the
carrier web 15 corresponding to the imaginary label no. 3, causing the
transport
pawl 46 to be again lifted clear of the carrier web. The transport slide 40
now re-
verses its movement, moving to the right according to FIGS. 6 and 7c. When the
skids 50 in FIG. 7d reenter the wave troughs of the carrier web 15 between the
imaginary label no. 2 and the imaginary label no. 3, the carrier web 15 is
held
clamped on the table 45 by the clamping member 52 in the zone of the imaginary
label no. 3. From now on the carrier web 15 is entrained to the right as
indicated in
FIG. 7e by an arrow on both the transport slide 40 and the carrier web 15.
According to FIG. 7f the transport slide 40 causes the carrier web 15 to
follow its
movement through a distance corresponding to a label spacing. Thereafter the
transport pawl 46 is again lifted clear of the carrier web 15 so that with the
next
pivoting cycle of the lever 22 the same sequence of movements results which
commences again as shown in FIG. 7a.
The present invention will now be described in greater detail with reference
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to FIGS. 1 to 5. To the extent possible, the same reference numerals as those
used for the known labeling apparatus of FIGS. 6 and 7 are applied.
FIG. 1 shows as detail the transport slide 40 of a labeling apparatus of the
invention which differs from the known labeling apparatus only in the
construction of
the transport slide and the improved entrainment of the carrier web 15 by the
trans-
port slide thereby accomplished. FIG. 1 shows the transport slide 40 in a view
from
below, that is, as seen looking from below at.the labeling apparatus shown in
FIG.
6. FIG. 2 shows the transport slide 40 of FIG. I in a sectional view taken
along the
line II-II of FIG. 1. FIG. 3 shows the transport slide 40 of FIG. 1 with the
flap 44
open. In the representation of FIG. 1 a length of the carrier web 15 reaching
about
from one end of the slide to the other end is in the transport slide 40. FIG.
4 shows
as a detail the transport pawl 46 of the transport slide 40 of FIG. 1. FIG. 5
shows
the transport pawl 46 in a vertical sectiorial view.
According to the representations of FIGS. 2 to 5 the transport pawl 46 has a
recess 54 extending over its effective width and receiving the clamping member
52.
According to the invention the clamping member 52 is constructed in a cutting-
edge-type configuration such that line contact is producible between the
clamping
member 52 and the carrier web 15 in a direction transverse to the feed
direction of
the carrier web 15. In the embodiment shown in FIGS. 1 to 5 the clamping
member
52 has several cutting edges 52a, 52b and 52c arranged adjacent to one another
in
the feed direction of the carrier web 15. The relative distance of the cutting
edges
52a - 52c to the carrier web 15 increases progressively in the feed direction,
as can
be seen in FIG. 2 where the cutting edge 52a already sits on the carrier web
15
whilst the cutting edge 52b is at some distance from the carrier web 15, and
the
distance of the cutting edge 52c from the carrier web 15 is greater still. The
cutting
edges 52a - 52c may be provided on a single body forming the clamping member
52. In the embodiment herein shown and described the clamping member 52 is
comprised of several blades 56a, 56b and 56c. The recess 54 is shaped such as
to
receive the blades 56a - 56c fixedly therein. When the housing 42 of the
transport
slide 40 is fabricated as an injection-molded part, the blades 56a - 56c may
be
placed in the mold as an insert prior to molding so that upon demolding the
trans-
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port pawl 46 is available as a finished part, as shown in FIG. 4. Arranged in
the
recess 54 are ribs 55 supporting the blades 56a - 56c in the feed direction
and
dividing the recess generally designated as 54 into several smaller recesses.
The
blades 56a - 56c are preferably made of metal as, for example, cutlery steel.
As
becomes apparent from FIG. 2 the blades 56a - 56c protrude from the transport
pawl 46 by equal amounts on the side of the transport pawl 46 facing the
carrier
web 15, and the blades 56a - 56c are fastened to the transport pawl 46 in such
a
way that in the clamping position shown in FIG. 2 they are inclined to the
carrier
web 15 relative to a perpendicular. As the transport slide 40 moves to the
right in
FIG. 2, first the blade 52a will make line contact with the carrier web 15.
With con-
tinued movement of the transport slide 40 to the right in FIG. 2, the
transport pawl
46 swivels progressively in clockwise direction about the axis 48, hence
causing
also the second cutting edge 52b and finally, with the transport slide 40
exerting a
correspondingly strong pull on the carrier web 15, the cutting edge 52c to
make line
contact with the carrier web 15 in order to progressively clamp the carrier
web 15 on
the table 45.
