Product guide for processing equipment

Guide elements are provided to be mounted on rotatable drive rods of a conveyor apparatus, preferably of the type for wet processing of thin electrical printed circuit boards or printed circuit film, as the same is subjected to acid, neutralizer, water, air, sprays, rinses or the like, as such thin materials are moved through the machine. The guides serve to keep the thin materials from falling out of their intended planar path of travel through the machine, but are readily removable, preferably in snap-on, snap-off fashion for ready conversion of the apparatus to handle thicker materials in which such guide elements are not needed. The guide elements may be mounted in staggered fashion across the apparatus and serially along the path of travel through the apparatus. The elements are configured to resist twisting and allow rotatable drive rods to continue to rotate while the elements are disposed on the drive rods, but without rotation of the guide elements.

BACKGROUND OF THE INVENTION 
The present invention is directed to the conveyance of small and/or thin 
materials through an apparatus, in which the materials are being 
processed, and more specifically to the conveyance of thin printed circuit 
boards or printed circuit film through a wet processing apparatus in which 
the thin materials may be subjected to sprays of etchants, rinse, drying 
air, neutralizer solutions or the like. 
Without intending to be limiting, some examples of processing equipment 
with respect to which the present invention is adapted, are equipment of 
the type disclosed in U.S. Pat. Nos. 4,015,706, 3,935,041, 3,905,827, 
3,801,387 and 3,776,800, the disclosures of which are herein incorporated 
by reference. 
The above-mentioned and other types of equipment, particularly in the wet 
processing art, have often come to employ rotatable drive rods extending 
transverse of the machine, having wheels or disks mounted on the drive 
rods, such that when the drive rods are driven, generally from an end 
thereof, the wheels rotate and engage and define a path of travel for 
printed circuit boards or other materials that are to be treated, as they 
pass through the apparatus from one end to the other. Some such apparatus 
is designed in the form of modular units, each adapted for perhaps a 
single treatment, such as a spraying treatment, with another adapted for 
rinsing treatment, another adapted for a drying treatment, etc. Other 
apparatus is of the built-up type wherein a single piece of equipment may 
have many processing functions therein. 
In the processing of materials, particularly in the processing of materials 
for use in the electronics industry, its has become more commonplace than 
rather than using rigid or semi-rigid printed boards, the "boards" have 
become increasingly thinner, to the extent that such materials approach or 
become more of a flexible "film". Indeed, in the art it has been known 
that circuits are constructed of thin flexible films that may then be used 
in various configurations, not limited to flat or planar configurations, 
such as in the nosecones of rockets and the like. 
Accordingly, as such materials requiring treatment have become thinner and 
thinner, or otherwise smaller and smaller, conventional guiding techniques 
have not always been successful, in that, in the case of films, the films 
have often tended to buckle and become jammed against drive rods in 
movement along their path, often helped in such buckling by the weight of 
etchants, sprays, or the like; in some cases, the films have dropped 
between adjacent rotatable rods, resulting in disruption of the treatment 
process. 
THE PRIOR ART 
The prior art has developed such that such thin films have been assisted, 
from time to time, by employing a plurality of thin guide wires running 
from one end of the apparatus to the other, often reasonably closely 
spaced in parallel configuration, such that a thin film can never depart 
significantly below the desired path of travel for it through the 
apparatus. Such wires have run from one end to the other of the apparatus, 
with many such wires being disposed parallel to each other. 
The present invention is directed to the recognition of and solving of a 
problem; namely, that of maintaining flexibility in the equipment so that 
is not dedicated to handling either thicker materials such as printed 
circuit boards, or thin materials such as printed circuit film, but 
wherein the equipment may be readily adaptable for handling one or the 
other. 
To this end, the present invention teaches the use of guide elements that 
may readily be mounted or demounted on drive rods, depending upon whether 
thin materials requiring the use of supplemental guides of any type are 
necessary or not. 
SUMMARY OF THE INVENTION 
The present invention is directed toward providing guiding means for thin 
materials being conveyed through processing equipment, in which the 
guiding means are adapted for mounting and removal relative to drive rods 
on which they are carried, without requiring demounting of the drive rods 
themselves. 
It is a primary object of the present invention to provide readily mounted 
and demounted guide elements, for drive rods of processing equipment. 
It is another object of the present invention to accomplish the above 
object, wherein the guide elements are provided with rails located 
generally in the plane of travel of materials through the apparatus. 
It is a further object of this invention to accomplish the above objects, 
wherein the guide elements are provided with a snap-on, snap-off 
connection to the drive rods, with at least one such connection to a drive 
rod for each said element. 
It is a further object of the present invention to accomplish each of the 
above objects, wherein the guide elements readily permit rotational 
movement of drive rods therein. 
It is still a further object of the present invention to accomplish each of 
the above objects, wherein the guide elements themselves permit corners of 
film or the like being guided to pass therealong and therebeneath free of 
obtrusive engagement with the elements themselves, particularly at 
downstream ends of the elements. 
It is a further object of the present invention to accomplish each of the 
above objects, wherein the elements include a stabilizer for protecting 
the elements against twisting during use. 
Other objects and advantages of the present invention will be readily 
apparent to those skilled in the art from a reading of the following brief 
descriptions of the drawing figures, the detailed description of the 
preferred embodiment, and the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings in detail, reference is first made to FIG. 1, 
wherein the apparatus of this invention is generally designated by the 
numeral 10, as comparing inlet end wall 11, outlet end wall 12, opposed 
side walls 13, an upper chamber wall 14, and a chamber floor (not shown in 
view of the foreshortening of the illustration). 
Articles being treated such as printed circuit film 15 are conveyed through 
the apparatus 10 from an upstream end thereof commencing at the inlet 
opening 17, and pass in the direction of arrow 16 to a downstream end that 
terminates at the outlet 18. 
As the articles 15 are being thus conveyed, an etchant, rinse or the like 
is delivered thereto from suitable spray headers 20 and 21, supplied by 
suitable supply lines, such as 19, 23 or the like, from any suitable fluid 
supply source (not shown), with the fluid thus being supplied from the 
headers 20,21 by means of suitable sprays 22, to impart the desired 
treatment fluid to upper and lower surfaces of the articles 15 that are to 
be treated. 
A plurality of generally parallel and transversely oriented drive rods such 
as 24,25 or the like, extend transversely of the apparatus between side 
walls 13 thereof, and outside one side wall are generally driven in unison 
by means not shown, but which is disclosed in the above-mentioned 
referenced patents. The drive rods have generally smooth or 
surface-serrated drive wheels 26 disposed thereon, such that the rotation 
of the rods in the direction shown in FIG. 1 will drive the wheels 26 in 
the direction shown. The wheels 26 are generally of an etchant-resistant 
synthetic rubber-like material, and in the aggregate define a plane that 
is a path of travel for articles 15 through the apparatus in the direction 
of arrow 16. The wheels 26 are generally disposed, many in number, along 
each of the rods 24,25, in staggered relation, across the apparatus. 
Thus, it is seen that etchant or other substance may lay on the upper 
surface of the material 15, and in the case where such material 15 is 
extremely thin, it may be caused to drop into the opening between adjacent 
rods 24,25 and the wheels 26 carried thereon. Alternatively, simply the 
force provided by the spraying action from nozzles 22 or the like, or 
drying air or the like, may cause the material 15, if it is sufficiently 
thin, to depart from the desired path of travel through the apparatus, to 
become obstructed by one or more wheels or associated drive rods of the 
like, or otherwise to become interfered with in the path of travel of the 
thin material 15 through the apparatus. 
To this end, a plurality of drive elements 30 are provided, preferably 
constructed as illustrated in FIGS. 2 and 3. The elements 30 are generally 
of one-piece molded plastic or like construction such as will be resistant 
to etching, rinsing, fluids or the like, and comprise an upper guide rail 
31, that is connected by means of an arcuate connection 32 at its 
left-most end (the end that would normally first see thin material to be 
passed thereover), and to be unconnected at its right-most end 33, to the 
rest of the element. The arcuate connection 32 is attached to the rest of 
the element, generally at the left-most end of a lower longitudinal rail 
34. The rail 34 is slightly longer than the distance between two adjacent 
rods 24,25, and is provided with two U-shaped rightwardly opening guide 
mounts 35,36, for mounting respectively over rods 24,25, as the element is 
moved rightwardly, in the direction of the arrow 37. In such movement, the 
mounting portion 35, which has a throat or opening of a dimension "a" will 
snap-over the slightly larger dimensioned "c" rod 24, such that the 
element 30 has to be snapped-off, at such time as removal of the element 
30 is desired from the rods. Thus, it will be seen that the rod 24 is 
snuggly received within the opening 38. At the same time, the rod 25 is 
slidingly received within the opening 40, which is preferably a slightly 
larger opening size "b" than the exterior dimension "c" of the rod 25, but 
that such arrangement permits ready removal of the mount 36 from the rod 
25, but in use prevents rotation of the element 30 with the rod 24, in 
that it confines the upward or downward movement of the element 30. While 
the mount 35 snaps onto the rod 24, it will be understood that the rod 24 
is free to rotatably slide against surface 38 during its driving rotation 
of the wheels 26 for conveyance of material 15 through the apparatus 10. 
A stabilizing bar 41 is comprised of integral projections extending from 
each side of the rail 34, as is best seen in FIG. III, and has an interior 
surface that merges with the arcuate surface 38, as indicated in FIG. 2, 
for engaging against a sliding surface of a rotating drive rod 24 therein, 
for stabilizing the element 30 against twisting in a clockwise or 
counter-clockwise direction as viewed in FIG. 3. 
In the application in a preferred situation, the elements 30 are disposed, 
many in number across the apparatus between front and back walls 13 
thereof, and it will be seen that the rails 31 extend over about 21/2 
spaces between adjacent rods 24,25. If desired, the rails 31 may be 
disposed such that a next adjacent one in transverse direction will 
commence with its upstream end 32 just prior to the terminal disposition 
of a downstream end 33 of a next-previous element, to give a substantially 
continuous guiding support to elements being conveyed, where desired. 
In accordance with the present invention, it will be seen that as many as 
200 guide elements 30 or more may be used with a given piece of equipment 
to provide adequate guiding of material being treated therethrough. At the 
same time, it will be apparent that when the equipment is desired to be 
used for treating materials that are not so thin or small as to require 
the use of guides of some type, the elements 30 may readily be unsnapped 
or removed, and the equipment is immediately ready for other use. 
It will also be apparent, particularly of the illustration of FIG. 3, that 
the upper surface of the rail 31 will form substantially a line of contact 
with material being conveyed thereover, in that the rail 31 is preferably 
of circular cross-section, with the other components, such as the rail 34 
and the mounts 35 and 36 being preferably of rectangular cross-section. 
The present invention thus allows a high degree of serviceability of the 
equipment, as well, because of the ready removability of the elements 30. 
It will thus be apparent that the desired ends of the invention are 
satisfied. Other modifications may be made in the details of construction, 
as well as in the use and operation of the present invention, all within 
the spirit and scope of the appended claims.