Power assist hide applicator

A mechanized power assisted apparatus for flattening and stretching wet tanned hides on a smooth flat plate preparatory to drying in the course of leather manufacture. The apparatus comprises support means holding a squeegee-type slicker element for positioning closely adjacent to a hide-carrying plate. The slicker element has a smooth straight edge which is rotatable in a plane parallel to the surface of the plate. The slicker support means is associated with a powered travel means for moving the support means in a plane parallel to and spaced from the surface of the hide-carrying plate and over a hide supported on that plate. Powered thrust means are associated with the slicker element for moving the element into and out of contact with the wet hide and for exerting force on the slicker element. Spaced apart control means are provided for actuating the power assist means for manipulating the slicker element over the surface of a hide in simulation of manual hide application.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a mechanized power assisted apparatus for 
applying tanned hides on a smooth flat plate preparatory to drying in the 
course of leather manufacture. 
Tanning of leather is an ancient art. From the earliest times, man has 
changed rough raw animal hides into supple wearable materials. This 
involves mechanical and chemical treatment of the hide to remove blood, 
lymph, adhering flesh, hair, etc. and enzymatic and bacterial action to 
render the hide soft and supple. These are wet treatments. The leather is 
commonly dyed and treated with oils and fats for lubrication, softness, 
strength and water-proofing. After dyeing and fat-liquoring, leather 
contains about 45 to 60 percent water and is commonly dried to about 14 
percent moisture. Chemical and physical reactions take place during 
drying. Loose tannins, dyes and oils spread uniformly, penetrate deeply 
and are firmly fixed. Uneven drying causes migration of unfixed tannin, 
dye and oil to the surface, resulting in undesirable dark stains and 
non-uniform appearance. 
A common industry technique of drying wet hides is so-called "paste 
drying." Hides are literally pasted by the grain side to large flat plates 
of adhesive coated glass, porcelain or metal, and then are passed through 
a tunnel dryer. After drying to the desired moisture content, the hide is 
stripped off yielding flat, smooth grain, large area leather sheets ready 
for finishing and fabrication into various leather goods. Alternatively, 
the wet hides may be vacuum dried after being similarly spread out on a 
flat smooth polished plate. Vacuum drying is faster but requires costly 
equipment. 
Whether to be paste dried or vacuum dried, it is essential that the wet 
hide be in intimate contact with the smooth planar surface without any 
entrapped air bubbles. The wet hide is applied to the surface and manually 
smoothed by means of a squeegee-type slicker element. This is most 
commonly in the form of a flat edged blade which is manipulated over the 
surface of the wet hide from the center to the edge working out any 
entrapped air or water between the hide and plate surfaces. At the same 
time, the hide is stretched somewhat increasing its area. This is tough, 
arduous work requiring great strength and staying power. Typically, in the 
course of a day's work, fatigue sets in toward the end of the day and 
productivity is materially reduced. The principal objective of the present 
invention is to provide a mechanical power assisted apparatus to perform 
this back-breaking task, with its attendant advantages of lessened 
fatigue, higher productivity, and more uniform product. 
2. The Prior Art 
No prior art pertinent to the invention is known. 
SUMMARY OF THE INVENTION 
Broadly stated, the invention is directed to a power assist hide applicator 
apparatus for flattening and stretching a wet hide against a smooth planar 
surface for drying. The apparatus is adapted for positioning closely 
adjacent to the smooth flat plate upon which a hide is adhered for drying 
according to conventional tanning practice. The apparatus comprises 
support means holding a slicker element for positioning closely adjacent 
to a hide-carrying plate. The slicker element has a smooth flat edge which 
is rotatable in a plane parallel to the surface of the plate. The slicker 
element support means is associated with a power assisted travel means for 
moving the support means in a plane parallel to and spaced from the 
surface of the hide-carrying plate and over an area substantially 
coextensive with the area of a hide supported on that plate. Power 
assisted thrust means are associated with the slicker element for moving 
the element on a path perpendicular to the hide-carrying plate into and 
out of contact with a wet hide carried on the plate and for exerting force 
on the slicker element. Spaced apart manually operable control means are 
provided for actuating the power assist means for manipulating the slicker 
element over the surface of a hide in simulation of manual hide 
application.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The invention is described with reference to use in connection with 
vertical hide-carrying plates as commonly used in tanneries for paste 
drying in tunnel dryers. It is to be understood, however, that the 
concepts of the invention are equally applicable for operation in a 
horizontal plane for smoothing and stretching hides on horizontal surfaces 
as are commonly used in vacuum drying. 
Referring now to the drawings, and particularly to FIGS. 1 and 2, there is 
shown one form of apparatus according to the present invention in vertical 
configuration. The apparatus includes a frame having left and right 
parallel widely spaced apart vertical posts or standards 10 and 11 
supported on a floor 12, as by feet 13 and 14, respectively. An upper 
horizontal guide rail 15, in the form of an elongated cylindrical tube or 
shaft, is supported at its opposite ends by brackets 16 and 17 which in 
turn are supported by standards 10 and 11, respectively. A corresponding 
lower guide rail 18 is supported by brackets 19 and 20. Together standards 
10 and 11 and rails 15 and 18 define a rectangular frame of size between 
about 4'.times.10' to 6'.times.12', corresponding generally to the 
dimensions of a rigid smooth surfaced hide-carrying plate 21 upon which a 
wet animal hide 22 is spread. As best seen in FIG. 2, the apparatus frame 
is positioned closely adjacent and parallel to the plate 21. In practice, 
the hide is pasted or otherwise adhered to the plate. Usually this is done 
at a work station preceding that of the applicator apparatus and the plate 
is moved into position on a traveling conveyor. 
An upper X motion carriage, indicated generally at 23, is supported on 
guide rail 15 for horizontal movement therealong. As best seen in FIGS. 3 
and 4, carriage 23 is supported on the guide rail 15 by means of a 
cylindrical bushing 24. For movement, one end of a sprocket chain 25 or 
similar linear drive means is secured to a bracket 26 forming part of the 
X motion carriage. Drive chain 25 extends horizontally to and around idler 
sprocket 27 supported on plate 28 from the top of standard 11 (FIG. 1), 
and thence horizontally to drive sprocket 29 supported by plate 30 from 
the top of standard 10. The drive chain then extends back to the X motion 
carriage where its opposite end is secured to bracket 31 supported on the 
bushing. Drive sprocket 29 is driven by an hydraulic or electric motor 32 
which is also supported by plate 30. 
A vertical plate 33 is supported by brackets 26 and 31 of the X motion 
carriage. Plate 33 in turn supports a bracket 34 which rigidly holds the 
top ends of a pair of parallel spaced apart vertical Y motion guide rails 
35 and 36. Guide rails 35 and 36 are of structure similar to horizontal 
guide rails 15 and 18. The lower ends of guide rails 35 and 36 are rigidly 
secured in a bracket 37 forming part of a lower X motion carriage, 
indicated generally at 38 (FIGS. 3, 4 and 6). Bracket 37 is secured to the 
back surface of a vertical plate 39. The lower carriage 38 is supported on 
lower guide rail 18 by means of a pair of bushings 40 and 41 secured to 
the front surface of plate 39. It will be seen that the upper carriage 23 
and lower carriage 38, along with guide rails 35 and 36, form a rigid 
assembly. Thus, when the upper carriage is driven to travel horizontally 
along upper guide rail 15, the lower carriage travels horizontally along 
guide rail 18. 
A Y motion carriage, indicated generally at 42, is mounted for vertical 
travel along guide rails 35 and 36. Y motion carrier 42 includes a 
cylindrical bushing 43 which engages guide rail 36 for vertical travel 
therealong. A pair of vertically spaced apart brackets 44 and 45 are 
secured to bushing 43 for travel therewith. The left hand edges of 
brackets 44 and 45 each have a pair of parallel spaced apart finger-like 
elements 46 and 47 (FIG. 5), each having on its inner surface a bushing 
plate 48 and 49, respectively, which engage guide rail 35 for maintaining 
Y carriage 42 stable in its vertical travel. 
One end of a drive chain 50 is connected at 51 to Y carriage 42. Drive 
chain 50 extends downwardly to and around idler sprocket 52 journaled for 
rotation between bracket 37 and plate 39 of lower X motion carriage 38. 
The drive chain then extends upwardly to drive sprocket 53 driven by motor 
54 supported on vertical plate 33 of upper X motion carriage 23. Thus, 
actuation of motor 54 causes the Y motion carriage to be driven vertically 
along guide rails 35 and 36. This may occur simultaneously with horizontal 
travel of the vertical guide rails and upper carriage 23 and lower 
carriage 38 along guide rails 15 and 18, respectively, by actuation of 
motor 32. 
A vertical plate 55 is supported from the front edges of brackets 44 and 45 
of the Y motion carriage. A cylindrical bearing cartridge housing 56 is 
secured to plate 55 with its longitudinal axis extending horizontally and 
perpendicular to the plate. A hub 57 is supported for rotation within 
housing 56 journaled by spaced apart ring bearings 58 and 59. A sprocket 
60 is mounted on one end of hub 57. Sprocket 60 is driven by drive chain 
61, in turn driven by drive sprocket 62 driven by motor 63, also mounted 
on plate 55. A ball spline 65 is mounted within hub 57 to rotate 
therewith. A splined shaft 67 extends through ball spline 65 for rotation 
with it and reciprocation in Z motion relative thereto. 
One end of shaft 67 is fitted with a hub 68 which is journaled by bearing 
69 for rotation relative to elongated plate 70. Plate 70 in turn is 
supported by piston rods 71 and 72 of air cylinders 73 and 74, 
respectively, which in turn are supported by plate 55. A slicker element 
in the form of a straight edged blade 75 is carried in a blade holder 76, 
in turn carried by hub 68 for rotation with shaft 67 and hub 57 when 
driven by motor 63. Blade 75 is disposed so as to be capable of applying 
pressure to the hide. It may be perpendicular as shown or may be disposed 
angularly relative to the surface of plate 21 and a hide carried by that 
surface in simulation of manual manipulation. Blade 75 is reciprocated 
toward and away from hide 22 by action of cylinders 73 and 74 and an 
adjustable controllable thrusting force is exerted to hold the blade edge 
in contact with the hide by the cylinders which are connected to a source 
of air under pressure. Alternatively, the slicker element may take the 
form of a small diameter elongated roller. 
Manually operable control means for motors 32 and 54 operating X and Y 
motions, respectively, motor 63 operating rotation of the slicker element, 
and flow of air to cylinders 73 and 74 to operate thrust motion of the 
slicker element, are preferably spaced apart from the applicator 
apparatus, but in close proximity so that the operator at all times may 
view the applicator operation. The control assembly is shown in FIGS. 8, 9 
and 10. A T-bar joy stick handle 85 is supported from a hub 86 journaled 
for rotation on bearings 87 within rectangular frame member 88. Frame 88 
is pivoted at 89 and 90 in a gimbal arrangement for rotation about a 
horizontal axis within a frame 91. Frame 91 in turn is pivoted at 92 and 
93 for rotation about a vertical axis within a fixed rectangular frame 94 
which is secured to a support panel 95 and spaced therefrom by a plurality 
of spacer posts 96. A thumb switch 97 actuates the system, as shown 
schematically in FIGS. 12 and 13 for actuating cylinders 73 and 74 for 
moving the slicker blade 75 into contact with a hide to be flattened and 
stretched. 
FIGS. 11 through 13 illustrate diagrammatically the power connections 
between the control assembly shown in FIGS. 8 to 10 and the several 
mechanical assemblies for operating the slicker element 75. Specifically, 
the means by which the actions initiated by manipulation of handle 85 are 
transmitted to the responsive mechanical elements are illustrated 
diagrammatically. In the hydraulic circuit of FIG. 11, a motor driven 
hydraulic pump provides a pressure/flow source of hydraulic fluid to the 
input ports of X, Y and Z servo valves. When a current flow from the 
electrical control circuit shown in FIG. 12 is directed to a servo valve, 
the servo valve will respond by shifting the spool of the valve in the 
direction dictated by the direction of the current flow and in proportion 
to the magnitude of the current. As described in detail hereinafter, the 
direction is dictated by the direction of movement of handle 85. 
Movement of the valve spool provides hydraulic pressure and flow to the 
actuator in the circuit motor 32, 54 or 63. The actuator then moves at a 
rate proportional to the spool movement, which in turn is proportional to 
the electrical current received by the current coil (103, 104 or 107) of 
the corresponding servo valve. When the direction of flow of the control 
current to the control coil is reversed, the valve spool shifts in the 
opposite direction and thus reverses the direction of movement of the 
actuator. A cross-over relief valve 100, as shown in FIG. 11A, is provided 
in each actuator circuit. This valve is a variable pressure safety device 
to limit the force available in the event of a stalled actuator. 
FIG. 12 illustrates the electrical control circuit. The X and Y bridges 
(potentiometers 101 and 102, respectively, both located on the control 
assembly) are both rate controlled systems. With the potentiometer wiper 
in the mid-position of its throw, no current will flow into the associated 
servo valve current coil (103 or 104). Upon moving the wiper from its 
mid-position, responsive to movement of handle 85 in its gimbal mounting, 
current flows in one direction through the solenoid valve current coil 
dependent upon the direction of movement of the handle. The farther the 
deviation of the wiper from its mid-position, the greater the current 
flow. Reversing the movement of the wiper to the other side of the 
mid-point on the potentiometer reverses the current flow direction through 
the servo valve current coil and again, the greater the movement of the 
wiper from the mid-point on the potentiometer, the greater the current 
flow. 
The Z control is a closed loop servo circuit. A potentiometer 105 on the 
control handle is the master and a potentiometer 106 on the Z actuator 
motor 63 is the slave. Whenever position of the wiper of the potentiometer 
on the slave doesn't correspond to that of the master potentiometer, an 
appropriate current in the current coil 107 actuates the servo valve to 
drive the Z actuator 63 and slave potentiometer wiper to a position on the 
slave potentiometer in correspondence with the position on the master 
potentiometer. Driving of the Z actuator correspondingly drives the 
slicker element 75. 
FIG. 13 illustrates the pneumatic circuit for actuating thrust force 
exerted on the slicker element. Air under pressure is filtered, pressure 
regulated and lubricated, prior to entry to an air solenoid valve. In 
normal operation, the air passes through the solenoid valve to the rod end 
of each air cylinder 73, 74 causing the slicker element 75 to remain at 
its fully retracted position. When the thumb switch 97 on the handle 85 is 
depressed, current flows through coil 108 and the air solenoid valve is 
actuated. This causes the air to be passed to the piston end of each air 
cylinder causing the slicker element to advance to the hide 22. The air 
pressure regulator is adjusted to attain the desired loading of the 
slicker element on the hide. The rate at which the slicker element 
traverses in or out is adjustable with the variable flow control. 
Rotation of the T-bar handle 85 drives the wiper of the master Z 
potentiometer 105. A limit stop of 105 degrees on either side of the 
mid-position is provided. This potentiometer the slave potentiometer 106 
and the current coil 107 of the Z servo valve constitute the Z drive 
closed servo loop. 
In Y motion, rotation of frame 88 on pivot shafts 89 and 90 with respect to 
frame 91 rotates gear 109. Gear 109 meshes with pinion 110 mounted on Y 
potentiometer shaft 111 giving a potentiometer wiper movement proportional 
to movement of frame 88. Springs 112 and 113 keep frames 88 and 91 biased 
to a neutral center position, with the two frames being parallel and the 
wiper of the potentiometer 102 at its mid-point. 
In X motion, rotation of frame 88 with respect to fixed frame 94 about 
pivot shafts 92 and 93 rotates gear 114 which meshes with pinion 115 
mounted on shaft 116 of X potentiometer 101 giving a potentiometer wiper 
movement proportional to the movement of frame 88. Springs 117 and 118 
keep frames 88 and 94 biased to a neutral central position with the two 
frames being parallel and with the wiper of the potentiometer at its 
mid-point. 
It is apparent that many modifications and variations of this invention as 
hereinbefore set forth may be made without departing from the spirit and 
scope thereof. The specific embodiments described are given by way of 
example only and the invention is limited only by the terms of the 
appended claims.