Impregnating machine for surface impregnating hides or similar products

An impregnating machine (1, 28) for surface impregnating hides (2) or similar products wherein an endless conveyor belt (3), with a transportation branch (5) traveling in a given direction (6), and a conveyor (16), presenting a number of endless belts (17), define a feed channel (19) for the hides (2); the feed channel (19) extending substantially up to a narrow passage (13) for the conveyor belt (3) and the hides (2); and the passage (13) being defined between an impregnating roller (11) and a deflecting member (7) facing the impregnating roller (11) and such as to impart to the transportation branch (5) of the conveyor belt (3) a radius of curvature (R1) equal to a relatively small fraction of the radius (R2) of the impregnating roller (11).

TECHNICAL FIELD 
The present invention relates to an impregnating machine for surface 
impregnating hides or similar products. 
In particular, the present invention relates to an impregnating machine for 
surface impregnating hides or similar products, the machine being of the 
type comprising conveying means defining a given path for the hides, and 
for feeding the hides in a given direction along said path; a cylindrical 
impregnating roller rotating in the opposite direction to said given 
direction, and presenting a given radius and a cylindrical outer surface; 
and a deflecting member for imparting a given curvature to a portion of 
said path; said path portion being located facing the periphery of the 
impregnating roller, and defining, with the periphery of the impregnating 
roller, a narrow passage for the hides; and said conveying means being, 
upstream from said passage, continuous conveying means arranged on 
opposite sides of said path to define a feed channel for the hides. 
BACKGROUND ART 
In EP-A-0 484 740, an impregnating machine is disclosed of the type 
described above, and wherein a hide conveying member, comprising a belt 
and defining the aforementioned advancement path for the hides, is wound 
about a deflecting roller defining the aforementioned deflecting member, 
and is positioned facing the impregnating roller to define therewith the 
aforementioned narrow passage for the hides. 
The impregnating roller of EP-A-0 484 740 is so operated that, at the noted 
narrow passage, its periphery travels in the opposite direction to that of 
the conveying member. 
Counter rotation of the impregnating roller in relation to the facing 
conveying member generates several problems stemming from the impregnating 
roller tending to push the hides back at the narrow passage. 
In order to avoid the above, in the machine manufactured in accordance with 
EP-A-0 484 740 several precautions where taken. As a first precaution, in 
order to impart a better traction to the hides, the deflecting roller was 
chosen as large in diameter as possible so as to keep the traction 
imparted by the conveying member to each hide at the noted narrow passage 
as aligned as possible to the portion of the hide arranged upstream from 
the narrow passage. As a second precaution, the noted feed channel for the 
hides was interrupted a predetermined distance from the narrow passage to 
allow insertion, between the outlet of the feed channel and the narrow 
passage, of a guiding blade an edge of which was arranged substantially at 
the narrow passage. 
The above precautions notwithstanding, the machines manufactured in 
accordance with EP-A-0 484 740 proved to be somehow unsatisfactory owing 
to the hides tending to jam between the guiding blade and the outlet of 
the feed channel. 
DISCLOSURE OF INVENTION 
It is an object of the present invention to provide an impregnating machine 
wherein the impregnating roller is operated in the opposite direction to 
that in which the hides travel, but which enables the hides to be fed 
smoothly and safely onto the impregnating roller. 
According to the present invention, there is provided an impregnating 
machine for surface impregnating hides or similar products, the machine 
comprising conveying means defining a given path for the hides, and for 
feeding the hides in a given direction along said path; a cylindrical 
impregnating roller rotating in the opposite direction to said given 
direction, and presenting a given radius and a cylindrical outer surface; 
and a deflecting member for imparting a given curvature to a portion of 
said path; said path portion being located facing the periphery of the 
impregnating roller, and defining, with the periphery of the impregnating 
roller, a narrow passage for the hides; said conveying means being, 
upstream from said passage, continuous conveying means arranged on 
opposite sides of said path to define a feed channel for the hides; and 
the machine being characterized in that said path portion presents a 
radius of curvature equal to a relatively small fraction of the radius of 
the impregnating roller; said feed channel extending substantially up to 
said passage. 
Said conveying means preferably comprise an endless conveyor belt 
presenting a transportation branch traveling in said given direction, the 
transportation branch defining said path portion and extending about the 
deflecting member to assume said given radius of curvature; and a conveyor 
cooperating with said transportation branch upstream from said deflecting 
member to define, with the transportation branch, said feed channel. 
According to a preferred embodiment of the above machine, said 
transportation branch comprises two contiguous portions in series in said 
given direction, and of which a first is located upstream and a second 
downstream from said deflecting member; said two portions forming a given 
obtuse angle; and the conveyor cooperating with said first portion. 
More specifically, said conveyor preferably comprises a number of endless, 
side by side belts; at least one transmission pulley for each said belt; 
and a deflecting block adjacent to said passage; the deflecting block 
being comb-shaped, and comprising a number of teeth extending parallel to 
said given direction; and each pair of adjacent teeth defining a fork for 
a respective said transmission pulley.

BEST MODE FOR CARRYING OUT THE INVENTION 
Number 1 in FIGS. 1 and 2 indicates an impregnating machine for surface 
impregnating a succession of hides 2 or similar products, and which 
comprises a conveyor belt 3 looped about two pulleys 4 (only one shown) 
and presenting a transportation branch 5 for successively receiving hides 
2 from a known feed device (not shown), and for feeding them along a path 
P in a given substantially horizontal direction 6. 
Machine 1 also comprises a deflecting member 7 located inwards of belt 3 
and cooperating with the inner surface of an intermediate portion of belt 
3 so that said intermediate portion presents a given radius of curvature 
R1. More specifically, deflecting member 7 cooperates with transportation 
branch 5 on which it defines two contiguous portions 8 and 9 in series in 
direction 6 and respectively up- and downstream from member 7 to form a 
given obtuse angle A. Member 7 preferably, but not necessarily, comprises 
a transmission roller with a radius R1 and mounted parallel to pulleys 4, 
so that transportation branch 5 is substantially in the form of an obtuse 
dihedron, the curved outer vertex 10 of which defines a curved portion P1 
of path P, and forms, on belt 3, the boundary between contiguous portions 
8 and 9. 
Machine 1 also comprises a cylindrical impregnating roller 11 facing 
deflecting member 7, located outside belt 3, and presenting a much larger 
radius R2 than the radius of curvature R1 of portion P1. More 
specifically, radius R1 equals a relatively small fraction of radius R2. 
Here and in what follows and, in particular, in the claims, the term 
"relatively small fraction" is used to indicate a fraction of the order of 
1/10. In particular, in the shown embodiments, the above fraction has a 
value of about 1/20. 
Roller 11 presents a cylindrical outer surface 12 defining, together with 
member 7, a narrow passage 13 for belt 3 and hides 2, and is powered in 
known manner (not shown) so that surface 12 travels in the opposite 
direction to direction 6 at passage 13, and carries a thin film (not 
shown) of dyeing liquid 14 applied in known manner to surface 12 by a 
known doctor blade 15 located upstream from passage 13 in the rotation 
direction of roller 11. 
Machine 1 also comprises a conveyor 16 located upstream from deflecting 
member 7, and in turn comprising a number of side by side belts 17, each 
looped about at least two pulleys 18a, 18b, the second of which is common 
to all of belts 17. Conveyor 16 cooperates with portion 8 of 
transportation branch 5, with which it defines a channel 19 for feeding 
hides 2 and extending parallel to direction 6. 
Conveyor 16 also comprises a deflecting block 20 adjacent to passage 13 and 
defining the output portion 21 of channel 19, which substantially extends 
up to passage 13. Block 20 is substantially comb-shaped, and comprises a 
number of teeth 22 for maintaining hides 2 firmly contacting belt 3, and 
which extend side by side and parallel to direction 6 along portion 21, 
and define respective forks 23, each housing in rotary manner a respective 
pulley 18a. 
More specifically, each tooth 22 presents a free end 24 substantially at 
passage 13, and two surfaces 25 and 26 forming an acute angle; surface 25 
is a flat surface facing transportation branch 5 with which it defines 
portion 21; and surface 26 is a curved surface facing and substantially 
tangent to surface 12 of roller 11. 
Operation of machine 1 is immediately discernible from the foregoing 
description. One point to note, however, is that, since the free ends 24 
of teeth 22 are such that output portion 21 of channel 19 extends 
substantially up to passage 13, and since surfaces 26 of teeth 22 are 
substantially tangent to surface 12 of impregnating roller 11, it is 
practically impossible for hides 2 or their front ends 27 (FIG. 2) to be 
pushed backwards by the friction produced by roller 11. In this 
connection, it should be pointed out that the friction between roller 11 
and hides 2 is minimized by the diameter of deflecting member 7, the 
relatively small radius R2 of which forms a path P substantially in the 
form of a broken line, and minimizes the contact area between roller 11 
and hides 2. 
A further point to note is the stabilizing effect of channel 19 on the 
shape of each hide 2, which enables the front end 27 to be "propelled" at 
full speed into and past passage 13, with no danger of the normally 
thicker end 27 being jammed beneath roller 11 inside passage 13. The 
stabilizing effect of channel 19 on the shape of hides 2, combined with 
the small contact area between roller 11 and belt 3, i.e. the relatively 
small portion of portion P1 of path P along which roller 11 interacts with 
hides 2, enables hides 2 to travel rapidly through passage 13, without 
being pushed backwards by roller 11, once passage 13 is engaged by front 
ends 27. 
The FIG. 3 and 4 variation relates to an impregnating machine 28 similar to 
machine 1, except that deflecting block 20 also comprises a plate 29 
extending crosswise to the traveling direction 6 of hides 2, located 
facing portion 8 of transportation branch 5 immediately upstream from 
passage 13, and substantially tangent to surface 12 of roller 11. More 
specifically, plate 29 is fitted to teeth 22, of which it substitutes for 
respective ends 24, and is located between pulleys 18a and passage 13. 
Machine 28 operates in exactly the same way as already described in 
connection with machine 1.