FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. APPARATUS FOR DYEING EDGES OF LEATHER PIECES
2.
1. (A) PROLET LTD.
(B) Bulgaria
(C) 62 Parvi May Str. 6400 Dimitrovgrad Bulgaria
The following specification particularly describes the invention and the manner in which it is to be
performed.
2
Technical Field
The invention relates to an apparatus for dyeing edges of leather pieces which is used
in the haberdashery-leather industry.
Background of the Invention
One of the basic technological o 5 perations in the leather-haberdashery industry is
dyeing edges of leather pieces by applying a water-soluble dye on the edges, whereas the
quality of the technological operation executed depends on the amount of dye deposited in
layers. The objective is to achieve not only colouration of the edge, but also smoothing
thereof by applying a thick layer of dye. Said working step is carried out repeatedly in order
10 to provide a sufficiently thick layer of dye. After applying the first layer, the dye applied is
usually polished using low-abrasive polishing brushes. When applying each layer of dye, the
dye is left to dry-up and then, the next layer is applied. To accelerate said process of drying,
driers may be used (60 to 1500С), and to achieve good quality, 3 to 5 separate applications of
dye shall be made on one piece, whereby drying is performed after each dyeing step.
15 WO 2014/045200 A1 discloses a machine for dyeing the edge of leather pieces
comprising a work surface for the leather to be dyed and a tool head, movable along the
work surface with a numerically controlled axis system. The tool head carries a tool for
dyeing the edges of leather positioned on the work surface. The machine also comprises a
vision system to acquire images of the leather to be dyed positioned on the work surface and
20 a computer that receives the images of the leather and processes the trajectories of the
toolhead to dye the edges of said leather. Said tool head comprises: a variable volume
chamber containing a dyeing liquid; an actuator for modifying the volume of said variable
volume chamber; a dispenser in fluid connection with said variable volume chamber
configured to apply dyeing liquid to the edge of leather to be dyed. Said variable volume
25 chamber comprises a cylinder and a piston sliding in said cylinder.
This known device for dyeing edges of leather pieces does not allow for collecting
the residual dye which reduces the efficiency thereof. Furthermore, disassembly of the tool
head is required for cleaning said device.
RO 131550 A1 discloses an apparatus for dyeing plane and convex narrow edges of
30 wide belts and strips made of leather or other materials by applying a convex thick dye film,
both on a flat and on a convex surface. The apparatus comprises a dyeing device consisting
of a dyeing cylinder which is provided with some circular channels of different depth and
width which takes over the supply dye or adhesive, a proximity sensor being mounted above
3
it to detect the amount of dye or adhesive in the space above the dyeing cylinder and, in case
the amount of dye is not sufficient, it seizes a compressor which starts automatically and
pushes the dye from a can into the space above the dyeing cylinder; the apparatus also
comprises a steel plate removing, if necessary, the excess of dye from the surface of the
dyeing cylinder, said plate being adjusted b 5 y means of some screws in order to carry out
thick uniform convex film on the edges of a piece without causing leaks on the lateral
surfaces of the previously dyed piece.
The size of the dyeing cylinder of the apparatus disclosed in RO 131550 A1is
comparatively large which reduces the ability for high-quality dyeing of sharp inner corners
10 and curves of leather pieces. In addition, the presence of channels on the dyeing cylinder
impedes washing-up of said dyeing cylinder.
An apparatus for applying dye on edges of leather pieces using a horizontally
disposed rotating dye-coated shaft is known. When the dye on the shaft comes into contact
with the leather piece, a part of the dye is transferred onto the piece edge. Coating the dyeing
15 shaft with dye is conducted by means of an additional wheel, having a trapezoid crosssection
/tapered to an angle of 45 degrees/ which is partly immersed in a bath with dye,
whereby the lateral wall thereof rests on the dyeing shaft wall. During rotation, the
additional wheel is coated in the bath with dye and the dye thus applied is then transferred
onto said dyeing shaft and, there from, onto the edge of the leather piece.(“GALLI”
20 S.P.A.Catalogue, 2015.)
The main disadvantages of said known apparatus are as follows: the diameter of the
dyeing shaft is not less than 12 - 15 mm which leads to serious problems in two main
directions:
1. The amount of dye transferred from the dyeing shaft onto the leather piece is
25 inversely proportional to the dyeing shaft diameter at the same thickness of the dye film
thereon. If there are two dyeing shafts – one of them having a diameter of 30 mm,and the
other one having a diameter of 7mm – both of which having a dye film applied with a
thickness of 1 mm, the amount of dye transferred from the dyeing shaft having a diameter of
7 mm onto the piece is significantly greater. It is not possible to achieve a diameter of the
30 dyeing shaft which is less than 12 – 15 mm in said known dyeing apparatus. This
considerably reduces the amount of dye transferred onto the leather piece which increases
the number of dye applications per piece. In order to achieve the required quality when using
a dyeing shaft having a diameter of 30 mm, it is necessary to dye one piece 3 to 6 times, and
when the dyeing shaft diameter is7 mm, the piece requires 2 or not more than 3 applications
4
of dye. This is due to the significantly lower force of dye holding /adhesion/ to the dyeing
shaft since the area of the shaft itself is smaller at the same thickness of the dye film on the
shaft.
2. From the process point of view, it is more difficult to dye pieces with acuteinner
angles using a larger shaft due to the greater radius and 5 the impossibility to reach the inner
areas of the sharp corner.
In addition to the above disadvantages, said apparatus has a complex mechanical
structure for actuating the coating shaft and the actuating wheel.There are also considerable
difficulties in washing the apparatuses from the dye, due to the large dimensions of the
10 shafts and the baths with dye.
Disclosure of the Invention
An object of the invention is to provide an apparatus for dyeing edges of leather
pieces which ensures transferring of a larger amount of dye onto the leather piece perone
application thus reducing the number of applications and, as a result of this, significant
15 reduction in the duration of the whole process step is achieved.
Another object of the invention is to simplify the dyeing shaft actuating structure.
An apparatus for dyeing edges of leather pieces according to the present invention
comprising vertically arranged dyeing head having a dyeing shaft connected to a motor
through a coupling, and a controller. The dyeing head comprises said dyeing shaft and an
20 eccentric pump, having a common rotation axis and connected to each other by means of a
channel-and-tube system for supplying dye to said dyeing shaft by said eccentric pump.The
dyeing shaft is provided with a plate for controlling the thickness of the dye film on said
dyeing shaft and said plate is arranged perpendicularly to the rotation axis and tangentially to
the lateral surface of the dyeing shaft. Said eccentric pump includes an eccentric cylinder
25 closed at the top by the bottom of a dye tank, wherein an opening for supplying dye to the
eccentric pump is formed. A pin mechanism and a process plug are mounted on the lateral
side of said eccentric cylinder and said pin mechanism consists of a sleeve closed at its one
end, said sleeve accommodating a spring and a spring-loaded pin; and said process plug
comprises an opening connected to a channel-and-tube system inlet for supplying dye to the
30 dyeing shaft.
Advantageously, the dyeing shaft of the apparatus has a diameter of 6 mm to 8 mm.
Preferably, said plate for controlling the thickness of a dye film on the dyeing shaft is
provided with a screw for adjusting the plate position.
5
In one preferred embodiment, the lower part of the dyeing head is encompassed by a
housing, wherein a shaft is incorporated in the bottom part and said shaft is provided with a
radial bearing sleeve for dyeing shaft bearing.
In advantageous embodiments, said coupling connecting the dyeing head to said
motor is a magnetic coupling comprising 5 magnets for the dyeing shaft being arranged
radially and incorporated into a holder which is attached to the dyeing shaft axis, and
magnets for the motor also being arranged radially and incorporated into a second holder
which is attached to the motor axis, whereby both holders have an equal number of magnets
arranged one above the other. There is a panel of a nonmagnetic material between both
10 holders on which the dyeing head is positioned so that both holders are positioned one above
the other.
Preferably, said second holder with the magnets, said motor provided with a motor
driver, an electrical power supply source, and said controller are accommodated in a box and
said panel of a nonmagnetic material closing the top of the box.
15 In other preferred embodiment the lower part of the dyeing head, the coupling and
the motor are encompassed in a vertically arranged tube which tube, in the lower end
thereof, is fixedly attached to a base accommodating the motor driver and the controller.
Preferably, the motor for actuating said dyeing shaft is a step motor or a DC motor.
Said controller is connected to a power supply source and to said motor driver.
20 In one preferred embodiment of the invention, the controller is a single-board
microprocessor system.
The advantages of the apparatus for dyeing edges of leather pieces according to the
invention are as follows: The dyeing shaft diameter is significantly smaller which ensures
the transfer of a greater amount of dye onto the leather piece per one application and, as a
25 result of this, the number of applications of dye onto the piece reduces which leads to
significant reduction of the duration of the whole process step. On the other hand a dyeing
shaft with a smaller diameter ensures easier and high-quality dyeing of pieces having acute
inner angles since such type of a shaft is able to reach the inner areas of the acute angle.
Both basic parts of the apparatus–the electrical part with the motor and the dyeing head – are
30 completely separated to provide for unhindered washing of the dyeing head at each change
of the dye colour, without disassembling the dyeing head members. The magnetic coupling
allows for sealing the apparatus electrical part, including the motor and the controller,
whereby increasing many times the apparatus reliability. Furthermore, the dyeing shaft
actuating structure is simplified.
6
Brief Description of Drawings
Figure 1 is a schematic diagram of an embodiment of a dyeing apparatus according
to the invention;
Figure 2а is a schematic representation of a dyeing shaft illustrating the principle of
5 formation of a dye film onto the dyeing shaft;
Figure 2bis a schematic representation of the dyeing shaft illustrating the principle of
dye transferring from the dyeing shaft onto a piece to be dyed;
Figure 3is a longitudinal section of the dyeing apparatus according to the invention;
Figure 4is a transverse section along the А-А line of Figure 3 which passes through
10 the eccentric pump;
Figure 5а is a longitudinal section of the dyeing apparatus illustrating a schematic
representation of the magnetic coupling;
Figure 5bis a transverse section of the magnetic coupling passing through the magnet
plane;
15 Figure 6is a front view with a partial vertical section of the apparatus for dyeing
edges of leather pieces;
Figure 7 is a front view with a partial longitudinal section of another possible
embodiment of the apparatus for dyeing edges of leather pieces according to the invention,
whereby the lower part of the dyeing head, the magnetic coupling and the motor are
20 encompassed by a vertically arranged tube;
Figure 8 is a perspective side view of the apparatus shown in Figure 7 with a partial
longitudinal section.
Modes for Carrying Out the Invention
Referring to Figure 1, a schematic diagram of an apparatus for dyeing edges of
25 leather pieces is shown, said apparatus includes a vertically arranged dyeing head 1 having a
dyeing shaft 4connectedto a step motor 2 by means of a magnetic coupling 3. According to
Figure 1, Figure 3andFigure 4, the dyeing head 1 comprises: said dyeing shaft 4and an
underlying eccentric pump 5 which have a common rotation axis 6 and are connected to each
other by means of a channel-and-tube system 7 for supplying dye to said dyeing shaft 4by
30 said eccentric pump 5.
Referring to Figure 2а and Figure 2b,a diagram for dye applying from the dyeing
shaft 4 onto the edge of a leather piece 10 is presented. The dyeing shaft 4 is equipped with
the following: a channel 11 of the channel-and-tube system 7 for supplying dye to said
7
dyeing shaft 4; a plate 12for adjusting the thickness of the dye film on the dyeing shaft 4and
said plate 12 is arranged perpendicularly to the rotation axis 6 and tangentially to the lateral
surface of the dyeing shaft4; said plate 12 is provided with a screw 15 for adjusting the
position of the plate 12; and a canal 13 for removing the excess of dye from the surface of
the dyeing shaft 4.Said channel 11 and 5 said plate 12 are attached to a bearing plate 14.
The dyeing shaft 4 of the dyeing head 1has a diameter of 6 mm to 8 mm.
Referring to Figure 3and Figure 4, there is shown the eccentric pump 5 which
includes an eccentric cylinder 17 with an eccentrically arranged rotation axis 6, common for
the dyeing shaft 4 and the eccentric pump 5. The top of the eccentric cylinder 17is closed by
10 the bottom of the dye tank 8 wherein an opening 18for supplying dye to the eccentric pump
5 is formed. A pin mechanism 19 is mounted on the lateral side of said eccentric cylinder
17which pin mechanism 19consists of a sleeve 20closed at its one end, said sleeve
accommodating a spring 21 and a spring-loaded pin 22. Also, process plug 23 is mounted in
the lateral wall of the eccentric cylinder 17 which comprises an opening 24connected to the
15 channel-and-tube system 7 inlet for supplying dye to the dyeing shaft 4.
The lower part of the dyeing head 4 is encompassed in a housing 25, wherein a shaft
27 is incorporated in the bottom part thereof having a radial bearing sleeve 26 for dyeing
shaft bearingandsaid housing 25 is provided with a foot 28.
The channel-and-tube system 7 for supplying dye from the dye tank 8 to said dyeing
20 shaft 4 comprises consecutively connected tubes 29, 30, 31 and the channel11 ending with a
nozzle(not shown)(Figure 1 and Figure 3).
Referring to Figure 1,Figure 5а and Figure 5b,there is shown the magnetic coupling 3
connecting the dyeing shaft 4 to the step motor 2.The magnetic coupling 3 consists of four
pieces of magnets35 for the dyeing shaft arranged radially and incorporated in a holder37,
25 being attached to the dyeing shaft axis 6, and four pieces of magnets 36 for the step motor 2
arranged radially and incorporated in a second holder 38, being attached to the motor axis.
There is a panel 39of a nonmagnetic material between both holders 37 and 38 (Figure 1).
The dyeing head 1 is positioned on the panel39of a nonmagnetic material so that the magnet
holder 37 of the dyeing shaft 1 is arranged coaxially above the second holder 38 of the step
30 motor 2.
In other embodiments, the magnets in each of the holders may be minimum two
pieces in each holder, and the maximum number depends on the size of the magnetic
coupling (the magnets may be 3, 4, 5, etc. in each holder). Both holders have an equal
number of magnets arranged one above the other.
8
Referring to Figure 6, the panel39 of a nonmagnetic material closes the top of a box
40, accommodating said second holder 38 with said magnets 36,said step motor 2, a motor
driver 41 for controlling of said step motor 2, an electrical power supply source 42 and a
controller43 for controlling the apparatus, being connected to the power supply source 42
and to the motor driver 5 41, as shown in Figure 1.The controller 43is a single-board
microprocessor system for controlling the operation of the whole apparatus. In other
embodiments, said controller may be a microprocessor system of another known type.
Figure 7 and Figure 8 show another embodiment of the apparatus for dyeing edges of
leather pieces according to the invention. The members of the dyeing head 1, the magnetic
10 coupling 3 and the motor 2 are the same as in Figures 1-5, except for the following: the
lower part of the dyeing head 1, the coupling 3 and the motor 2are encompassed in a
vertically arranged tube 44 which, in the lower end thereof, is fixedly attached to a base 45
accommodating the power supply source 42,the driver 41 and the controller 43.
The principle of operation of the apparatus for dyeing edges of leather pieces
15 according to the invention is as follows:
The dyeing shaft4 is actuated by the step motor 2 controlled by the controller 43.
Other types of electrical motors with controlled revolutions also may be used for actuating
the dyeing shaft 4. The motion from the step motor 2 to the dyeing shaft 4 is transmitted by
the magnetic coupling 3, as shown in Figure 1, Figure 5а and Figure 5b.The magnets in both
20 holders 37 and 38 are oriented so as to attract mutually (Figure 5а).When rotating, the step
motor 2 rotates also the holder 38 with the four magnets 36of the step motor 2. As a result of
the attraction between magnets 35 and 36of both holders, the holder38 of the dyeing shaft 4
also rotates in the same direction and with the same speed. Thus, the motion is transmitted
from the step motor 2 to the dyeing shaft 4 in a completely contact-free way.
25 The distance between both holders37 and 38is determined based on the thickness of
the panel 39of the nonmagnetic material, the thickness of the dye tank bottom and the air
gaps required for the free rotation of both holders. This distance may not be greater than 5
mm so as to ensure transmission of sufficient torque. If the distance is greater, the attraction
force decreases and the torque transmitted between both holders decreases dramatically.
30 Principle of operation of the eccentric pump 5.When the dyeing shaft 4 rotates about
the rotation axis 6, the eccentric cylinder 17 rotates as well. Due to the eccentrically arranged
rotation axis 6, the eccentric cylinder 17 begins to rotate so that point “А“ (Figure 4)on the
lateral wall of the eccentric cylinder 17 moves along the inner wall of the dye tank 8 in the
direction specified by an arrow in Figure 4. The dye enters in the eccentric pump 5 through
9
the supply opening 18. When moving, the eccentric cylinder 17 closes the supply opening 18
and the dye having entered the pump 5 is pushed from the eccentrically moving cylinder 17
towards the pin mechanism 19. The spring-loaded pin 22 of the pin mechanism 19 follows
the outline of the eccentric cylinder 17 closing the volume enclosed between point A of the
eccentric cylinder 17 and touch point of the spring-l 5 oaded pin 22 with the eccentric cylinder
17 in a certain moment, and does not allow the dye to pass behind the spring-loaded pin 22.
Thus, the pressure within said volume between point “А“ of the eccentric cylinder 17and the
spring-loaded pin 22of the pin mechanism 11 increases. The pressure generated pushes the
dye through the channel-and-tube system 7 inlet to the dyeing shaft 4. The actions described
10 are executed repeatedly.
Referring to Figures 2а and 2b, the principle of forming the dye film 9 with the
required thickness on the coating shaft 4 is shown. The fresh dye enters in the channel 11of
the channel-and-tube system 7 and after flowing out from the channel 11, the dye adheres to
the dyeing shaft4 which rotates in the direction shown in Figure 2а and Figure 2b. The dye is
15 entrained by the dyeing shaft 4 and, through the adjustment plate 12, forms a film 9 of dye
onto said dyeing shaft 4, while the excess of dye is removed and, through the canal13for
removing the excess of dye, is discharged towards the dye tank8. The film thickness on the
dyeing shaft 4 is determined based on the distance between the dyeing shaft 4 and the plate
12, whereas this distance is adjusted by the adjustment screw 15. When screwing up the
20 adjustment screw 15,the distance between the adjustment plate 12 and the dyeing shaft
4increases, whereby the dye film 9 on the dyeing shaft 4 increases.
When the dye film 9 with the required thickness is formed on the dyeing shaft 4, the
leather piece 10 approaches the dyeing shaft 4, moving in the direction specified by an arrow
in Figure 2b. When the leather piece 10 touches the dye film on the dyeing shaft 4, as a
25 result of the adhesion /adhesion force/, the dye is transferred from the dyeing shaft 4 onto the
leather piece 10. The adhesion of the dye to the piece 10 shall be greater than the adhesion to
the dyeing shaft 4 so that the dye may be transferred from the dyeing shaft 4 onto the leather
piece 10. Since the adhesion force of the dye depends also on the area to which it adheres –
the smaller the area of the dyeing shaft 4 /its diameter, respectively/, the smaller the adhesion
30 force thereto and, therefore, the ability of the shaft to hold the dye on itself.
As seen from the disclosure, the smaller the diameter of the dyeing shaft, the easier
the dye will be transferred onto the piece. The dyeing shaft 4 of the apparatus according to
the invention has a diameter of 6 mm to 8 mm/the diameters of the existing apparatuses are
as twice as big/.
35
10
WE CLAIM:
1. An apparatus for dyeing edges of leather pieces, characterized in that the apparatus
comprising a vertically arranged dyeing head (1) having a dyeing shaft (4) connected
to a motor (2) through a coupling (3), and a controller (43);the dyeing head (1)
comprises s 5 aid dyeing shaft (4) and an eccentric pump (5), having a common rotation
axis (6) and being connected to each other by means of a channel-and-tube system
(7) for supplying dye to said dyeing shaft (4);the dyeing shaft (4) is provided with a
plate (12) for controlling the thickness of the dye film on said dyeing shaft (4) and
said plate (12) is arranged perpendicularly to the rotation axis (6) and tangentially to
10 the lateral surface of the dyeing shaft (4);said eccentric pump (5) includes an
eccentric cylinder (17) closed at the top by the bottom of a dye tank (8), wherein an
opening (18) for supplying dye to said eccentric pump (5) is formed; a pin
mechanism (19) and a process plug(23) are mounted on the lateral side of said
eccentric cylinder (17),said pin mechanism (19) consists of a sleeve closed at its one
15 end (20), said sleeve accommodating a spring (21)and a spring-loaded pin (22); and
said process plug (23) comprises an opening (24) connected to a channel-and-tube
system inlet for supplying dye to the dyeing shaft (4).
2. The apparatus according to claim 1, characterized in that said dyeing shaft(4)has a
diameter of 6 mm to 8 mm.
20 3. The apparatus according to claims 1 and 2, characterized in that said plate (12) for
controlling the thickness of the dye film (9) on the dyeing shaft (4)is provided with a
screw (15) for adjusting the plate position.
4. The apparatus according to claim 1, characterized in that the lower part of the
dyeing head (1)is encompassed by a housing (25), wherein a shaft (27)is incorporated
25 in the bottom part thereof, and said shaft (27) is provided with a bearing sleeve
(26)for dyeing shaft bearing.
5. The apparatus according to claim 1, characterized in that said coupling (3)
connecting the dyeing head (1) to the motor (2) is a magnetic coupling comprising
magnets (35) for the dyeing shaft (4), being arranged radially and incorporated into a
30 holder (37) which is attached to the rotation axis (6) of said dyeing shaft (4), and
magnets (36) for the motor (2), also being arranged radially and incorporated into a
11
second holder (38) which is attached to the motor axis, whereby both holders (37, 38)
have an equal number of magnets arranged one above the other, and there is a panel
(39)of a nonmagnetic material between both holders (37, 38), and said dyeing head
(1) is positioned on said panel (39) so that both holders (37, 38) are positioned one
5 above the other.
6. The apparatus according to claims 1 and 6, characterized in that said second holder
(38) with the magnets (36), said motor (2)provided with a motor driver (41), an
electrical power supply source (42), and the controller (43) are accommodated in a
box (40) and said panel (39) of a nonmagnetic material closing the top of the box
10 (40).
7. The apparatus according to claim 1, characterized in that the lower part of the
dyeing head (1), the coupling (3) and the motor (2) are encompassed in a vertically
arranged tube (44) which tube (44), in the lower end thereof, is fixedly attached to a
base (45) accommodating a motor driver (41) and the controller (43).
15 8. The apparatus according to claims 1, 6 and 7characterized in that said motor (2)for
actuating the dyeing shaft (4) is a step motor or a DC motor.
9. The apparatus according to claims 1, 6 and 7characterized in that said controller
(43) is connected to the power supply source (42) and to said motor driver (41).
10. The apparatus according to claims 1 and9, characterized in that said controller (43)
20 is a single-board microprocessor system.