US3353470A - Automatic conveying device - Google Patents

Description

NOV. 21, 1967 s O ZANE 3,353,470

AUTOMATIC CONVEYING DEVICE Filed April. 19, 1965 5 Sheets-Sheet l N Q Q Q \Q \9 I NVENTOR. 20mm of 0 Zfl/VE B g H z NOV. 21, R 5 Q ZANE AUTOMATIC CONVEYING DEVICE 5 Shets-Sheet 2 Filed April 19, 1965 INVENTOR. m @ON/JLD J0. ZQ/VE BY 2 .4 H- Lds'v-L A ec-W7 Nov. 21, 1967 R. S. O. ZANE AUTOMATIC CONVEYING DEVICE 5 Sheets-Sheet .5

Filed April 19, 1965 w n Q 3 R m v m Nov. 21, 1967 R. s. o. ZANE 3,353,470 1 AUTOMATIC CONVEYING DEVICE Filed April 19, 1965 5 Sheets-Sheet 4 INVENTOR I Fem/240 d? 0 Zq/vf BY 8 L. H-Ou Nov. 21, 1967 R; S Q ZANE I 3,353,470

AUTOMATIC CONVEYING DEVICE Filed April 19, 1965 5 Sheets-Sheet 5 754 52 mo 6 a 6.9 6 5 48 74 /50 INVENTOR.

,Qomqm J 0 ZQ/VE /48 BY 9 1 H- QM *1 /46 #5 ma dais/v7- United States Patent 3,353,476 AUTOMATIE CONVEYING DEVIQE Ronald S. O. Zane, 2572 Hamner Ava,

Norco, Calif. 71760 Filed Apr. 19, 1965, Ser. No. 449,223 Claims. (CI. 95-94) ABSTRACT OF THE DISCLOSURE A device for automatically developing dental X-ray plates. The device has a holder for X-ray plates suspended from a rod, a pair of facing Walls with guideway channels sized to matingly receive opposite ends of the rod, an elevator for moving the rod up and down through a fixed distance, a series of X-ray developing baths, a driving mechanism for the elevator, and an electrical control system for automatically energizing the driving mechanism at predetermined intervals. The guide-way channels serve to guide the X-ray plate holder from bath to bath, in proper sequence, as the elevator is driven up and down by the driving mechanism at properly timed intervals, under the influence of the electrical control system, to assure an optimum immersion time for X-ray plates in the holder in each of the X-ray developing baths.

This invention relates to a means capable of automatically carrying out the successive immersion of objects to be liquid-treated for predetermined periods of time in liquid baths. More particularly, the invention relates to such a means having special adaptability for the automatic development of exposed dental X-ray plates.

The common use of the X-ray as a tool for the examination of human teeth by modern-day dentists is well known. Because of the current emphasis on frequent dental check-ups for the early detection and treatment of tooth decay, and other dental ills, and other factors contributing to greater X-ray use in dental ofi'ices and clinics, almost every dentist is now faced with the necessity of processing increasing numbers of dental X-ray plates in the daily conduct of his practice. Such processing involves, of course, the developing of exposed X-ray plates, which operation is typically performed on the premises by a dental assistant, or other employee, and, upon occasion, by the dentist himself. X-ray developing work, as presently carried out, adds substantially to the overhead cost of a dental oifice since it is a time-consuming chore which requires alert supervision throughout.

Exposed X-ray plates are now developed in a darkroom by first immersing them in a developer solution for a preselected period of time, typically about 3 and one-half minutes; removing them from the developer solution and immersing them in a first water bath; removing them from the water bath and placing them in a fix solution, normally for about minutes; taking them from the fix solution and placing them in a second water bath; and finally removing them from the second Water bath and drying them in a stream of warm air, after which they are ready for the dentists inspection and use. The foregoing description does not include all of the details of a typical X-ray plate developing operation (for example, it makes no mention of temperature control of the various liquid baths employed, nor of the water bath immersion, or rinsing, times) but it is complete enough to illustrate the time-consuming and burdensome nature of X-ray processing and the reason why it adds so significantly to the overhead cost of running a dental office. In addition to its overhead cost disadvantage, the X-ray plate developing procedure as presently practiced has other drawbacks, perhaps less directly manifested but just as real.

35,353,476 Patented Nov. 21, 1967 For example, as often happens during a typical working day in a busy dental office, when there is no one immediately available to handle a particular X-ray processing job, the developing work must be postponed. This results in a work output, and consequent earning rate, slowdown insofar as the dentist is concerned and, additionally, adds to the normal burdens of apprehension, inconvenience and time consumption borne by his patients as a natural consequence of their need for dental services.

I have now invented a means for automatically accomplishing the development of dental X-ray plates, by the use of which the foregoing disadvantages of present-day manual developing techniques are largely overcome. My automatic developing means, hereinafter referred to as the automatic developer, is adapted to receive exposed X-ray plates and guide them through the necessary solution dipping, Water rinsing, and drying steps of the developing procedure as described above. The automatic developer, in its preferred embodiment, is equipped with signalling means for letting the operator know when the plates have been completely processed, thus reducing the necessity of supervision to a minimum.

It is thus a principal object of this invention to provide a means for automatically accomplishing the development of exposed X-ray plates, thereby substantially eliminating the tedious, costly, and time-consuming supervisory requirements of presently employed developing procedures.

It is another object of the invention to provide an X-ray developing technique so characterized as to permit the immediate development of exposed dental X-ray plates in dental ofiices with substantially no interruption of higher priority work, professional or otherwise.

It is still another object of the invention to provide means to enable dentists to transmit dental examination results to patients more rapidly, thereby reducing the normal fear, inconvenience, and time loss concomitants of dental work to a minimum.

Other objects, features and advantages of my invention will become apparent as the description thereof proceeds.

The structural character and manner of operation of my automatic developer will be more readily understood by reference to the accompanyin drawings, of which:

FIGURE 1 is a plan view of a preferred embodiment of the automatic developer, showing a carrying rack for dental X-ray plates disposed in suitable starting position therein;

FIGURE 2 is a longitudinal section of the automatic developer taken along line 2-2 of FIGURE 1;

FIGURE 3 is a view similar to the FIGURE 2 view, showing the X-ray plate carrying rack in a different position to illustrate a critical phase of operation of the auto matic developer;

FIGURE 4 is a section of the automatic developer, taken along line 4-4 of FIGURE 2;

FIGURE 5 is a fragmentary View of the automatic developer in transverse section, taken along line 5-5 of FIGURE 2;

FIGURE 6 is an enlarged fragmentary view, mostly in section, showing the linkage between certain moving parts of the automatic developer, taken along line 6-6 of FIGURE 2;

FIGURE 7 is a fragmentary elevational view of a limit switch in an electrical control circuit for the automatic developer and a moving part of the developer which makes actuating contact with the switch, taken along line 7-7 of FIGURE 4;

FIGURE 8 is an enlarged, fragmentary elevational view, partly in section, showing the interlinkage of certain parts of a key mechanism in the automatic developer, taken along line 8-8 in FIGURE 4;

end walls and 12, respectively. The bottom and walls of the housing are separate members which are fastened together at their meeting edges by nail means, not shown.

It is not necessary that the housing be made of wood, and

any other structural material suitable for the purpose can be substituted as desired. For example, the housing can be formed of a suitable plastic material, of which many types are well known, and, in fact, as presently contemplated, this will be preferable to wood for commercial production purposes.

Firmly glued to the oppositely facing inner surfaces of side walls 6 and 8 of housing 2, in transversely'opposite and mirror-image relationship, are two arrayed groups of flat, precision shaped sections of Plexiglas, as shown in general at 14 and 16, respectively, on the drawings. The Plexiglas sections are of equal thickness and so shaped and spaced apart on their backing side wall surfaces as to form a maze-like series of slots, or passages, therebetween, suitable as guideways for moving parts later to be described. As will later appear evident, it is not necessary that the guideway defining section pieces be made of Plexiglas and they can be constructed of another plastic material, wood, metal, or the like. All that is required of the material is that it be amenable to some form of treatment to yield section pieces of proper shapes and sizes which can be afiixed to the walls of the housing in proper orientation.

It should be pointed out that it is not necessary, for purposes of this invention, to affix separate section pieces to the housing walls to form guideways if equivalent guideways are otherwise obtainable. Thus, the purposes of the inventionare satisfied if suitable guideways are incorporated directly in the walls of the housing, either by molding the walls with appropriate slotted recesses or raised portions with slot-like passages of suitable character, therebetween. An equivalent expedient is the use of secondary plates with built-in guideway patterns in lieu of Plexiglas section pieces. Where this expedient is employed, the secondary plates are molded, cast, or otherwise formed separately from the housing walls and later fastened to the walls in proper working orientation. Other ways of achieving the same result will suggest themselves to those skilled in the art from the teachings herein.

Disposed within housing 2 is an elevator 18, consisting of a framework of generally rectangular cross section having four upright slide members, 20, 22, 24 and 26, situated at its four corners, respectively. The upright slide members are of equal height, and they are tied together at their upper ends by four metal straps, 28, 30, 32, and 34, respectively. As FIGURE 1 shows, tie straps 28 and 30 are of equal length and longer than straps 32 and 34, which are also of equal length. The upright slide members are of generally square cross section and hollow interior, somewhat resembling sections of square drain pipe, but with important dilferences as will later be noted. The two shorter tie straps, 32 and 34, are fastened, by rivet means, to separate pairs of the four upright slide members, respectively, and the same thing is true of longer tie straps 28 and 30. The drawings clearly depictthe manner in which the tie straps and the upright slide members fit together to form elevator 18, hence little more need be said here on that subject. Suflice it to say, that the four upright slide members are so oriented as to dihedrally define the four corners of elevator 13, much as square fence posts at the corners of a fence around a rectangular yard dihedrally define the volume enclosed by the outer surfaces of the fence, and that the long tie straps (28 and 33) are fastened to the facing surfaces of two pairs of the slide members, whereas the short tie straps (32 and 34) are fastened to the outer, oppositely facing, surfaces of two other pairs of the slide members, respectively. This construction of parts and manner of assembly is particularly well illustrated in FIGURE 1. The reason for the inboard disposition of long tie straps 28 and 30, relative to the. volume defined by the corner dihedral planes of elevator 18, will become evident as the description of the invention, and particularly the further structural'details of slide members 20, 22, 24' and 26, proceeds.

As FIGURES 2 and 3 show, long tie straps 28 and 30 are so positioned that their upper edges fall in a common horizontal plane, and the same thing is true of short tie straps 32 and 34. While the common horizontal plane of the upper edges of the long tie straps is different, in the illustrated embodiment of my invention, from that common to the upper edges of the short tie straps, this is a non-critical design feature of that particular embodiment, and it is within the scope of my invention to utilize tie straps so sized and positioned as to have all of their upper edges coplanar, or in different planes, or to reverse the direction of elevation difference between the long tie straps and the short ones from that depicted in the drawings. It is also, of course, within the scope of the invention to utilize an elevator of square, rather than rectangular, corner distribution, or to otherwise deviate from the design particulars of the drawings in noncritical ways. Many such deviations will be suggested to those skilled in the art from a complete understanding of the manner of functioning of my automatic developer as taught herein.

While the structural members of elevator 18 are of metallic construction, it is not necessary that this be the case, and the elevator parts can be fabricated of a suitable plastic or other material adequate for the purpose if desired. In many instances aluminum is a satisfactory material for the elevator parts, but in other instances it might be desirable to substitute stainless steel, an acidresistant plastic, or other material not subject to attack by corrosive or solvent liquids therefor. The reason for the latter preference will soon become obvious,.if not already so, in view of the known liquid immersion utility of my automatic developer, hence will not be belabored here.

As will appear from the above description, elevator 18 is essentially the skeletal frame of a box-like structure without bottom-defining members. The elevator fits, bottom side down, within housing 2 in laterally symmetrical relationship therein, but closer to one end of the housing than the other. The clearances between the frame members of the elevator and the two side walls and nearer end 'wall of the housing, respectively, are relatively close for reasons which will later become apparent. The manner in which elevator 18 is supported within housing 2 and, consistent with its name, raised and lowered therein, will be described in detail below.

As previously indicated, uprightslide members 20, 22, 24 and 26 are of hollow construction and generally square cross section, with two of their dihedrally related sides flush against a short and long one of the tie straps, respectively. The structural relationship between the uprights and tie straps is such that each of the former has an inwardly facing side disposed parallel to the inner surface of one of the side walls of housing 2. The side opposite to this, which is, of course, outwardly facing, is not flat, as are the other three sides of the upright slide members, but is, instead, of stepped configuration, as shown at 20a on the drawings, with an L-shaped lip 38 projecting outwardly therefrom.-0ne leg 40 of the L shaped lip is in line with the riser-like portion of the 20a step configuration, and the other leg 42 extends 5 parallel to the lower tread-like portion thereof for a distance equal to the tread width.

L-shaped lip 33 is integral with the upright slide member to which it is attached and the lip-riser-tread structure thereby formed defines a channel which receives rail-like member 44, the latter being anchored against movement relative to housing 2 and described in greater detail below, in vertically slidable relationship for elevator stabilization and guidance during its travels within the housing. Each of the other three upright slide members has a channel similar to that described above by obvious reference to slide member 20. The only differences among the slide member channels are that the mouths of the two disposed on the same side of elevator 18 face towards one another, the reason for which will subsequently become clear. Consequently, the foregoing description of the channel configuration of a specific one of the upright slide members is sufficient to teach the configurations of all members, and to avoid a confusing proliferation of symbols on the drawing the parts of only the described channel are numbered thereon.

There is no difiiculty in fabricating slide members of the type described, as l have discovered by forming such parts from thin gauge sheet aluminum utilizing bending, and other techniques well known to those skilled in the art. It is not necessary that the members be made from aluminum or in the above-suggested manner, and, as previously indicated, it is preferable in many instances that they be made of a material more resistant than aluminum to attack by corrosive liquids. Neither is it necessary that the upright slide members be of thinwalled, hollow construction, as illustrated, and they can be solid, or thick-walled, if desired. The thin-walled construction is preferable, however, because of its lower weight characteristic.

Rail-like member 44, hereinafter referred to simply as rail, or track, 44, which mates in vertically sliding relationship with the channel of upright slide member 20, as heretofore indicated, is the projecting edge of a thin strip of plexiglass fixedly superimposed, by glue means, over the nearest (to upright slide member Ztl) end piece 46 of the group 14 cluster of groove forming plcxiglass sections on side wall 6. While the proximity to each other of upright slide member 20, side wall 6 and group 14 of plexiglass sections, which makes the interengagement of the slide member channel and rail 44 possible, has not previously been expressly pointed out, it has been implicity disclosed by the descriptions of those parts and the applicable portions of the drawings incorporated therein by reference.

Turning again to the description of rail 44, plexiglass section 46 is sufficiently thick, as FIGURE 1 shows, to hold the rail far enough away from side wall 6 to permit nonbinding movement of the outer flange of the slide member 20 channel in the space therebetween during functioning of the pictured mechanism. The relative dimensions of the slide member 20 channel and rail 44, and the positioning of each part with respect to the other, are so adjusted as to permit free sliding movement of the channel relative to the rail, while, at the same time, insuring directional guidance therefor. Each of the other three upright slide members, 22, 24 and 26, is positioned in matingly slidable engagement with a counterpart member to rail 44 comprising the cantilevered edge of a strip of plexigiass fixedly superimposed over the nearest end section of the applicable one of groups 14 and 16 of groove forming plexiglass sections. Thus as FIGURE 1 illustrates, the four corners of elevato 18 are held in place by upright slide members with integral channels in vertically sliding engagement with the projecting edges of four cantilevered strips of plexiglas anchored to the four end sections, respectively, of groups 14 and 16 of the groove forming plexiglass sections.

Because of its corner support design, the length of elevator 18 is fixed by the spread distances (which are equal) along side walls 6 and 8 of the aforesaid groups 14 and 16, respectively, of plexiglass sections. As previously indicated, and evident from the drawings, the two groups of plexiglass sections are directly across from and mirror images of each other, and hence of equal spread distance along their respective backing walls. The sizes, shapes, and relative positions of the here-involved parts are so determined as to permit free up-and-down movement of elevator 18 within housing 2 under the guiding influence of rail 44 and its three structural counterparts of previous reference, which act as corner holding means to maintain the elevator on course during its operating periods and furnish confining support therefor at other times.

The illustrated embodiment of my invention functions by causing elevator 18 to rise automatically from its lowest point through a fixed vertical distance to a maximum elevation and then return, at predetermined time intervals. Each lift of the elevator carries a load of X-ray plates out of a liquid bath stationed at its lower terminus, and with the aid of a cooperating member with oppositely oriented projections (later described in detail) which ride in the grooves or channels between the plexiglass sections of the aforesaid groups 14 and 16 thereof, the moving elevator advances the X-ray plates to either another liquid bath or to a drying zone, depending upon the stage of operation, during each of its round trip travel cycles.

Hereinafter the aforesaid grooves or channels between groups 14 and 16 of the plexiglass sections will be referred to as guideways 14a and 16a, respectively. Everything previously said regarding the class of suitable materials of construction for the guideways 14a and 16a defining members, the plexiglass section pieces of repeated previous reference, is equally applicable with respect to rail 44 and its three structural counterparts, also of repeated previous reference, for keeping elevator 13 on the track. It is not necessary that these guide rails be supported as shown in the drawings, and described above by reference thereto, and they can be supported by any suitable means occurring to one skilled in the art in the light of the present teachings.

Elevator upright slide members 20, 22, 24 and 26 are connected at their lowe ends to rods 48, 50, 52 and 54, respectively, which, in turn, are pivotally anchored to pivot pins 66, 68, '70 and 72, respectively. As FIGURES l and 4 show especially well, the thus-pivoted rods 48, 50, 52 and 54 are all disposed planarly parallel to the side walls of housing 2 and each is spaced, for the most part, away from the nearest side wall surface the same distance, this being substantially equal to the perpendicular distance of the linkage joint between it and its coop crating slide member on elevator 18 from the wall surface. The two rods nearest each side wall (rods 48 and 5t), and 52 and 54, respectively) extend outwardly in different direction from a common moving pivot engagement site at one end of a shaft 64 perpendicular thereto, said shaft being of sufiicient length to extend transversely across housing 2 and form such moving pivotal contact at both ends with the two pairs of rods, respectively, to oute end linkage with their respectively cooperating elevator slide members.

The subject rods, 48, 50, 52 and 54, are made of relatively thin strap metal, and each is characterized by a slight offset bend, shown at a, b, c and d on the drawings for the four rods, respectively, between its fixed pivot point (that is, where it is pivotally anchored by one of the aforesaid pivot pins) and its moving pivot engagement site with shaft 64. As the drawings illustrate, the lever arm distance between the fixed pivot point of each r d and its inner end juncture with shaft 64 is substantially shorter than that between the pivot point and the site of the outer end interlinkage of the rod with the elevator 18 structure of previous description. There is nothing magical about this particular lever arm ratio and it is a design feature of the illustrated embodiment of my invention which can be altered as desired, so long as the change is not so drastic as to render the device inoperable. In this connection, and as those skilled in the-art will appreciate, variation of the aforesaid lever arm ratio is a legitimate way to control the lift height of elevator 18 and therefore well within the noncritical modification areas, and hence scope, of my invention.

The principal reason for the offset configurations of the subject rods is to permit the inner termini of each pair coengaged with the same end of shaft 64 to so coengage while their main portions remain in coalignment. Such coalignment is, at least to some extent, necessitated by the equal spacing of the upright slide members of elevator 18 from the side walls of the housing, and the manner of linkage of those rods to those members. The offset bends in each pair of the 48, 50, 52 and 54 rods connected to the same end of shaft 64 extend oppositely from each other, as shown particularly well in FIGURES 1 and 4, for reasons obviousin the light of the foregoing.

For reasons which will be increasingly appreciated as the description of the invention proceeds, those pivot points of rods 48, 50, 52 and 5 situated on oppositely facing surfaces of sidewalls 6 and 8 of housing 2 are in mirror-image relationship to each other. This, plus the fact, implicit from the foregoing, that shaft 64 must of necessity be horizontally disposed, makes it obvious that the members of each pair of the aforesaid rods extending in the same direction from the shaft, and therefore necessarily disposed at opposite sides of the housing, respectively, are parallel to each other at all times during the operation of the pictured mechanism. Since, as will appear presently, there is another pivoted rod in that mechanism, rods 48, 50, 52 and 54 will, to avoid confusion, be hereinafter referred to as side pivot rods or pivoted side rods. Pivot pins 66, 68, 7 0 and 72 for the side Pivot rods are screws which pass freely through properly sized and located openings in their respectively associated rods. The screws are threadedly achored to two wooden spacer blocks 74 and 76 of equal size and configuration attached to side walls 6 and 8, respectively, in transversely opposite relationship within housing 2; screws 66 and 68 being fastened to spacer block 74 and screws 70 and 72 to spacer block 76. The spacer blocks are affixed to the side walls of the housing by glue means and they provide anchor bases for pivot screws 66, 68, 78 and 72 sufiiciently offset from the side Walls to bring the pivoted side rods into their proper positions of alignment relative to the elevator upright slide members with which they cooperate. Each of the screws 66, 68, 70 and 72 has a washer between its head and the side rod for which it serves as a pivot pin, and a couple of washers between its anchor base spacer block and the side of the rod opposite the screw head. The screws are not drawn sufficiently tight against their respectively adjacent washers to bind, but provide snug fitting pivot joints while leaving sufficient tolerances between the various parts of the joints to allow free movement between the side rods and their individually sandwiching Washers. The washers between the spacer blocks and the side rods, in addition to providing low friction flanking surfaces for the side rods as they pivot around their pins, serve as shims to compensate for the offset deviations of the rods oriented with the deviation bends toward the housing side walls, and thus insure pivotal freedom of those rods by holding them free of binding contact with spacer blocks 74 and 76.

The up-and-down movement of elevator 18 within housing 2 and the character of the mechanical interplay between the lower end of each of the upright side members of the elevator and the outer end of its cooperating side rod requires a sliding pivot type of interlinkage for joinder, of those parts. For purposes of simplicity, this interlinkage mechanism, which is identical for each of the four pairs of connected parts, will be described by specific reference to the joint between upright slide member 20 and side rod 48, this particular one being shown in enlargement in FIGURE 6. Basically, the joint is nothing more than a pin fixedly secured to upright slide member 20 and passing through a slotted opening of previous reference near the outer end of side rod 48 in perpendicular relationship to the rod. More specifically, the pin is the shank of a small bolt 78, which passes through aligned openings in opposite walls of upright slide member 20 so located as to assure the perpendicular pin-side rod relationship above referred to and depicted in the drawings.

Bolt 78 is secured in place by means of a nut 80 threaded thereon to snug fitting tightness against the outer surface of the wall of slide member 20 through which the shank protrudes. The receptive slot for bolt pin 78 in side rod 48, shown at 82 on the drawings, is of sufficient width to permit non-binding passage of the bolt pin therethrough, but of a length substantially greater than this, as the drawings illustrate. The reason for this, as will subsequently become more apparent, is to provide travel room for bolt pin 78 in the slot as the lever arm distance on the rod from its pivot point at screw 66 to the pressure acting point on elevator 18 varies with the vertical displacement of the elevator during its travel cycles.

As the drawings show, the aforesaid slot is transversely centered in side rod 48. The lower walls of upright slide member 20 across the path of side rod 48 in its illustrated position are slotted from the bottom to a sufiicient height to permit unhindered movement, of the indicated pivotal and sliding nature, of side rod 48 relative to bolt pin 78 during operation of the automatic developer. The resulting slots in the slide member walls, shown at 84 and 86, respectively, on FIGURE 6, are in proper alignment with the lay of side rod 48 and their widths, which are equal, suificientiy greater than the thickness of the side rod to provide for its non-binding passage therethrough.

While, as previously indicated, the three elevator slide member-side rod joints shown in the drawings, but not specifically referred to here, are structurally similar to that just described, they will differ, of course, in nonstructural features, such as, in some instances, direction of the slide member from the pivot point of the side rod, etc. These differences are, however, of so trifling a nature as to require no further discussion and the structural character of each of the non-described joints will, it is believed, be obvious from the foregoing description of the illustrative linkage mechanism considered conjunctively with the drawings.

As explained above, elevator 18 rides up and down along fixed guide rails and through fixed limits of travel during operation of the pictured embodiment of my invention. Pivoted side rods 48, 50, 52 and 54, have been shown to rotate around fixed pivot points intermediate their ends with their outer extremities at all times in a combined sliding and pivotal relationship with the pins (bolts) secured in the bottom four corners of the aforesaid elevator, respectively. To this point, the description of the drawings has proceeded in what could be considered a reverse direction, that is, from the structure farthest removed from the control and actuating means of the pictured'mechanism, backwards through the chain of mechanical energy transmitting elements toward the prime source of the energy. This would probably be an unduly confusing method of description in many cases, but it is here felt to be, by virtue of the unusual nature of the subject matter, less confusing than the more orthodox route of delineative progression through a machine or mechanism from its power source and along the path, or paths, marked by the flow of mechanical energy therein.

Returning now to the detailed description of the drawings, the power for moving elevator 18 is transmitted to it, through the interlinkage arrangement between rods 48, 50, 52 and 54 and the upright slide members of the elevator, from shaft 64. This is accomplished by means of slide-pivot interengagement of the two ends of the shaft 9. with the two pairs of inner ends of the aforesaid side rods, respectively. It will thus be seen that each of the side arms act as a first-order lever through which a force applied to its inner end is transmitted at its outer end to an upright slide member of elevator 18 to which that end is pivotally and slidably attached in the above-described manner. Shaft 64 is of round cross section throughout its length, but has two annular shoulders near, and the same distance from, its two ends. respectively, beyond each of which it is of concentrically reduced cross section and pintle-like appearance and function. The annular shoulders are shown at e and f on FIGURE 4, the distance of each from the nearest end of the shaft being such as to provide ample, but not excessive, axial distance along the pintle-like end of the shaft to nonbindingly accommodate the flanking inner ends of two of the side rods upon which the shaft acts. Hereinafter, the pintle-like ends of shaft 64 will be referred to as pintles g and h, respectively.

The mechanical linkages between pintles g and h and the inner ends of their cooperating side rods are quite similar structurally to the linkages between the screws afiixed to the bottom ends of the elevator upright slide members and the outer ends of the side rods. The linkages at the two pintle sites are similar to each other, except that each is in mirror-image relationship to the other, and hence, for the sake of simplicity, only the pintle g connection, shown in enlargement in FIGURE 8, will be here described in detail. The pintle h connection will be clearly understandable from the following description considered in conjunction with the drawings which illustrate it.

Turning now to the drawings, and particularly FIG- URE 8, it will be seen that pintle g passes transversely through slotted openings in side rods 48 and St the opening in the former being shown in solid line at 48a and the latter in dotted outline at 50a. Slotted openings 48a and 50a are transversely centrally located in their side rods 48 and 50, respectively, and are similar to their counterpart openings in the other ends of the side rods except not as elongate because of the shorter range of longitudinal travel of the pintle relative to either side rod, by comparison, for example, with the range of longitudinal travel of bolt 78, in a longer lever arm portion of side rod 48 than occupied by said pintle. The disparity in slot length between the shorter and the longer lever arm of the side rod is explained by a well known mathematical principle, which will be better understood after the following description of the manner in which movement is imparted to the side rods, and ultimately to elevator 18, by shaft 64. It is, of course, implicit from the foregoing description that all of the slots in the short lever arm sections of side rods 48, 50, 52 and 54 are of the same size, shape and rod positioning, and that the same is true of all of the slotted openings in the outer extremities of the longer lever arms of the rods.

As FIGURES 4 and show, pintles g and h extend in oppositely pointing directions substantial and equal distances past the planes of the facing surfaces of their respectively adjacent spacer blocks, the primary reason for this being to provide pintle axial distance safety margins suflicient to preclude any likelihood of side rod slippage from the end of either pintle. To permit such pintle extension, spacer blocks 74 and 76 are appropriately slotted as shown at 74a and 760, respectively, to provide hollow spaces therein for pintle travel during operation of the pictured mechanism. Since, as will presenlty be considered in more detail, shaft 64, in operation, travels a substantially vertical path of oscillation, slots 74a and 7601 are both of vertical disposition to accommodate this character of movement on the part of pintles g and h, respectively, therein. The two spacer block slots are equally dimensioned and, since, as previously indicated, shaft 64 extends tranversely across housing 2 in perpendicular relationship to its side walls, the slots are in mirror-image relationship relative to each other on their opposite sides of the housing.

The above-noted vertical oscillating movement is imparted to shaft 64 by an oscillating arm 88 having a transversely central slot, as shown at 83a, through which shaft 64 passes, and pivoted to a bracket 90 attached to end wall 12 of the housing in the position shown on the drawings. Oscillating arm 88 is transversely centrally positioned within housing 2 and disposed perpendicularly to shaft 64. It is pivotally fastened, by means of a pivot pin 92, of the well known type having end stops snapped into mating grooves around its periphery to prevent migration of the pin from its work station during operation of the depicted mechanism, to a link 94 which transmits mechanical energy thereto from a crank to which it is, in turn, pivoted. The pivotal connection between link 94 and oscillating arm $8 is located about one-third of the distance from the linkage joint between the arm and shaft 64 to the pivotal connection between the arm and bracket 99. Thus, oscillating arm 88 functions as a second-order lever in that force is applied to it intermediate a point of fixed pivotal support and a point at which the force is transmitted to another member, in this case shaft 64.

Bracket 96 is formed from relatively thin metal sheet stock in the shape of an L, and is fastened to end wall 12 by two screws 8 and 100, which pass through two holes in one of its legs to anchor it flush against the surface of the wall, as shown in FIGURE 5. The other leg of the L extends directly outwardly from approximately the vertical centerline of the end wall, and it is to this outstanding leg that oscillating arm 88 is pivoted, this being accomplished by means of a short bolt 162 passing through aligned openings in the arm and bracket. Bolt 102 is maintained in place by a nut 104 drawn to proper tightness to pull the arm and bracket sufficiently close together to prevent wobble of the former during its pivotal movement about the bolt, yet not so tight as to create binding frictional resistance between the arm and the bracket.

During operation of the illustrated embodiment of my automatic developer, oscillating arm 88 is urged through radial oscillations about the pivot bolt Hi2 by alternating up and down movements of the link 94, thus causing its outer end, to the right as viewed in the drawings, to move continuously up-and-down through a narrow arc defined by the upper and lower positional limits of the arm shown in FIGURES 2 and 3, respectively. The elevational location of bracket 50 on end wall 10 is roughly halfway between the upper and lower swings of the outer extremity of oscillating arm 88 in its alternating up and down movement, as will be evident from a study and comparison of the arm positions in FIGURES 2 and 3. While this particular bracket position is not critically acute for purposes of my invention, it represents a preferred operating height for the pivoted end of oscillating arm 88 because the horizontal component of travel of the outer, swinging end of the arm is minimal at this pivot elevation. This is desirable in order to approximate, as nearly as possible, true vertical oscillation of the outer arm 38, and thereby substantially achieve that type of motion in shaft 64.

It will now be apparent that the up and down movements of elevator 18 are brought about by the transmission of mechanical energy, from a power source as yet undefined, through link 94 to oscillating arm 88, the energy being so directed as to cause the arm to oscillate radially through a narrow are about a fixed pivot. The unpivoted end of arm 88 transmits its oscillating motion to transverse shaft 64, which in turn transmits it to the inner ends of side rods 48, 5t), 52 and 54 through its slotpintle linkages therewith. Since, as previously explained, two of the side rods are controlled by each pintled end of shaft ed, and the two on one pintle act in unison with their counterparts on the other pintle, the motions of the four side rods responsive to the urging of shaft 64 will be described by specific reference to rods 48 and 50, the two rods adjacent side wall 6 and illustrated in their positional extremes in FIGURES 2 and 3.

Directing attention now to FIGURE 2, elevator 18 is there shown at its lowest position of travel, sometimes herein referred to as its lower terminus, which, as might be evident from what has already been disclosed regarding the principal purpose and manner of operation of the pictured embodiment of my invention, is its normal positional status between programmed cycles of actuation thereof. Since the procedural particulars of the here-involved automatic developing process have not been clearly described as yet, it is necessary to note, at this point, that elevator 18 is at rest in its FIGURE 2 position most of the time, even during periods of active use of the automatic developer. Only at comparatively rare intervals, which are determined in advance, and program-incorporated into an automatic control system for the developer, later to be explained in detail, is the elevator caused to rise from its lower terminus location, When the elevator finally does move, at the command of the aforesaid automatic control system, it typically makes only one round trip to its highest point of travel, this being illustrated as previously noted, by FIGURE 3, and then settles down to rest at its lower terminus until again urged into action, after the proper time interval, at the bidding of the control system.

FIGURE 2 shows, better than words can explain, that l the design configurations, and interlinkage network, of

the various mechanical parts between shaft 64 and the four lower corners of elevator 18 are such as to create an inverse-position relationship between the outer end of oscillating arm 88 and the elevator in the sense that energizing movement of the former, in either the up or down direction, is translated by the intervening channels of mechanical energy flow into a reverse-direction movement of the latter. This is well illustrated by FIGURE 2, which shows a concurrence of low elevator and high oscillating arm extremity positions, as well as by FIGURE 3, which shows just the reverse positional relationship be tween the two parts.

Referring now to FIGURE 2 which, for reasons made clear above, represents the normal starting position for movement of elevator 18, the energizing pulse for such movement is manifested, as a result of energy flow from a source subsequently to be disclosed, to link 94 by a downward pull on pivot pin 92 by said link. This pull, acting through the pivot pin, causes oscillating arm 88 to swing downwardly about its pivot point at bracketed bolt 102 and, in turn, pull shaft 64 down at its slot 88a interlinkage therewith. The downward movement of shaft 64 acting at the points of contact of its pintle g in slots 48a and 48b of side rods 48 and 50, respectively, pulls the inner ends of those side rods down and causes them to pivot about their fixed pivot points at screws 66 and '68, respectively. A clearer mental picture of the latter action can perhaps be formed by looking at FIGURE 8, which shows an unobstructed view, in enlargement, of the inner ends of side rods 48 and 50 in their FIGURE 2 positions.

The downward movement of the inner ends of side rods 48 and 50, and their consequent pivoting around screws 66 and '68, causes their outer ends to see-saw upwardly and thereby urge elevator 18 in that direction as a result of pressure on upright slide members 20 and 22 at their slide-pivot linkages with the side rods, respectively. This mechanical chain reaction continues until link 94 reaches its lowest point of travel, as illustrated in FIGURE 3, whereat the outer end of oscillating arm 88 is also at its lowest point, which means that the inner ends of side rods 48 and 50 have been forced to their lowest point and the outer extremities of these rods, and hence elevator 18, have reached their zenith. The described series of events is followed immediately by return of link 94 to its highest point of travel and consequent reoccurrence of those events in reverse sequence, in the sense that the parts move in opposite directions, to complete a full cycle of elevator travel and bring it to rest in its FIGURE 2 position.

After return of the elevator to its lower terminus, the actuating movement of link 94 ceases, under normal operating conditions, until it is again induced to perform in the described manner. Although already pointed out, it is repeated for emphasis that side rods 52 and 54 function in unison with side rods 48 and 50, respectively, during the lifting and lowering of elevator 18. The only difference between the performances of the two pairs of side rods, are that the former transmit their forces to upright slide members 24 and 26, respectively, of the elevator, whereas the latter transmit theirs to slide members 20 and 22, respectively, and the former operate adjacent side wall 8, whereas the latter operate adjacent sidewall 6, of the housing 2.

Suflicient detail as to the structure and manner of functioning of elevator 18, its guidance hardware and that portion of its drive system mechanism so far discussed, has been given to adequately reveal, without the need of further elaboration, the total structural and mechanical fabric thereby encompassed. Thus, certain things not heretofore expressly spelled out will nevertheless be fully apparent from the foregoing description, examples of such being the means and manner of physical support for elevator 18, the reason why shaft 64 is always horizontally aligned, the geometrical necessity for the need of slot-type openings at slide-pivot joint sites, to name a few. The term slide-pivot joint, as here employed, is a coined generic term which, for lack of a better one, is used to denote all joints in which a pivot, or pivot-like member, moves in a slot in a separate lever member, and it includes the two similar, but slightly different, types of joint previously referred to herein as slot-pivot joints and slot-pintle joints, respectively, and by other terms of similar import. While the mechanical and structural aspects of the subject apparatus are many, because of the number and complexity of interengagement of the involved parts, enough has been disclosed to teach, in conjunction with the drawings, the structure and manner of functioning of the apparatus to those skilled in the art.

Returning now to discussion of the flow paths for the transmission of drive energy to elevator 18, from a source as yet undefined, and proceeding in the reverse, or upstream, direction heretofore pursued, link 94 is pivotally fastened to crank 96 by means of a pivot pin 103, of the same type as pivot pin 92, with peripheral grooves around its ends into which stop members are snapped. Pivot 103 passes through aligned openings in the link and crank members, the one in the link being near its bottom end, and the other being longitudinally offset from a receptive hole in the crank for a crankshaft 101 which extends from a small gearhead motor 99. The relative dimensions of pivot pins 92 and 103, and the receptive openings therefor, in the interlinked parts, as well as the spacing of the interlinked parts along the pins, are so adjusted as to permit free turning of the parts about their pivot pins and relative to each other.

Link 94 and crank 96 are properly sized sections of metal bar stock, although they can be constructed of other suitable material or materials, such as any of those referred to above in the discussions of satisfactory alternative materials for construction of the structural members of elevator 18, side rods 48, 50, 52 and 54, and other parts of the pictured apparatus. The outer end of crankshaft 101 has a flat spot on its periphery to provide an anchor base for a set screw, and this end of the shaft is fitted into a longitudinally off-center hole, previously referred to, running perpendicularly through crank 96, the flat spot being oriented toward the nearest end of the crank. A set screw 97 is threaded into a tapped hole in the end of the crank, connecting with the opening for crankshaft 101 therein, and tightened to locking contact with the flat spot on the periphery of the crankshaft. This fastening arrangement permits crank 96 to turn synchronously and in eccentricity with, and in a plane perpendicular to, crankshaft 101.

Gearhead motor 99 is a small electric motor attached by bolt fastening means, as indicated at a5, 93, 91 and 39 on the drawings, to the upright leg 37 of an L-shaped support bracket positioned as shown with its other leg secured to the floor of housing 2 by screw means (not shown). Crankshaft 101 extends outwardly from the gearhead motor 9% to its above-described connection with crank 96. The drawings, and particularly FIGURES 2, 3, 4 and 5, illustrate the described arrangement of parts, and the means by which they are fastened in place and interconnected, within housing 2.

Gear motor 99 supplies energy to drive elevator 18 through its periodic cycles of travel while acting under the guiding influence of an automatic control circuit which functions in a manner later to be described. The motor thus acts as a servomechanism, which, upon receipt of activating impulses from the control circuit, automatically commences to operate crankshaft 101, which thereupon transmits its motion to crank 96, causing the latter to turn eccentrically around the axis of the shaft in the direction indicated by the curved arrows on FIGURES 2 and 3. The crank, by virtue of its pivotal linkage with link 94, causes the pivot point of the latter to describe a circular orbit about the axis of the crankshaft. The circular travel of link 94 at this pivot point is translated into reciprocative travel at its other pivot point (pivotal connection with oscillating arm 83), the travel pattern of the latter being one of oscillation through a small, flat, and substantially vertical arc. There is a concurrence of high are point and high circle position of the two pivot points on link 94, respectively, and the same is true of the low points of pivot point travel, as FTGURES 2 and 3 illustrate. One complete orbit of the lower (crank) pivot point of link 94 corresponds to one complete oscillation (one up and one down movement) of its upper (oscillating arm 88) pivot point.

The oscillating movement transmitted to oscillating arm 88 from link 94, through pivot pin 92, is further transmitted' through interconnecting hardware, the structure and manner of functioning of which have been previously described in detail, to elevator 18, inducing the latter to move in a direction determined by the direction of movement of the oscillating arm. It will be apparent to those skilled in the art that each complete orbit of the lower pivot site of link 94 results in one complete cycle of up and down travel of elevator 18. Because of this synchronization of movement, it is important to correlate the starting and stopping of motor 99 with the correct travel phases of elevator 18 to assure automatic cut-off of the motor at the precise instant that the elevator reaches its lower terminus. With this kind of correlation, the elevator is in its proper position of rest between cycles of travel, and in the proper starting position to ascend when the motor again starts up. This kind of motor-elevator synchronization is not difficult of achievement, as will appear from the description of the automatic motor control systern to follow.

As previously explained, the relationship between the arcing movements of oscillating arm 88 and the up and donw travels of elevator 18 is inverse, meaning that the extreme upward displacement of the arm corresponds with the lowest position of the elevator. Accordingly, FIGURE 2, which shows this orientation of parts, represents the heretofore discussed quiescent phase of the motor and elevator system obtaining between the periodic excursions of the latter, and the starting positions for all moving parts of the system awaiting startup of the motor. FIGURE 3, of course, represents the halfway, or upper limit, point of the elevators travel cycle, and the corresponding positional orientation of the parts of the elevator drive system at that point.

It goes without saying that motor 99, crank 96, and link 94, as well as various items of accessory hardware for those parts, are all so configured, spaced within housing 2 and relative to each other, and geometrically oriented to assure unhindered cooperation thereof toward the common goal of feeding the proper kind and quantity of oscillatory energy to oscillating arm 88. The pivot hole locations in link 94 and crank 96, as shown on the drawings, are merely illustrative, and not critically definitive, of the possible pivotal arrangements for the parts in question. In this connection, those skilled in the art will appreciate that other pivot hole locations are operably possible, and that no skill beyond that of the ordinary artisan to whom this teaching is directed is required for the selection of such hole sites. The same thing is true relative to the selection of a suitable elevator drive motor for purposes of my invention.

The principal requirement of the elevator drive motor is that it have adequate torque capacity for the indicated purpose, and this is no problem, since motors with such capacity are readily available on the market. A preferred feature of the motor is that it have inherent braking means to rapidly reduce its coast-down time when switched off. This feature is desirable in order to minimize the possibility of elevator coast past its terminal station after switch-off of the drive motor, as a result of momentum energy in the motor, and is found in those cornmercially available motors which have built-in magnetic brakes. It is not essential, however, that the motor be self braking since, in the event it is not, it is well within the skill of the routineer in the art to devise and apply an external brake of some sort to a suitably receptive moving part, such as crank 97 or crankshaft 101. As one example of such expediency, I have prepared a makeshift external brake by placing a helical spring, under tension, around crankshaft 101 between the upright leg of motor bracket 87 and crank 96, with its ends bearing on those two members, respectively. The effectiveness of such a brake is enhanced by providing a layer of friction material, such as felt, on the facing surfaces of the motor bracket and crank in the areas of helical spring contact therewith.

Although by now it will be apparent to those skilled in the art, it is perhaps worthy of note that the lift height of the side rods, and hence the travel distance of elevator 18, can be varied by increasing or decreasing the radius of circular orbit of pivot in 103 around the axis of crankshaft 101. This radial distance adjustment is easily made by simply changing the longitudinal spacing between the openings for pivot pin 103 and crankshaft 101 in crank 96. Another way of accomplishing variation in the lift height of the side rods is to vary the location or" the pivotal connection between oscillating arm 88 and link 94 on the former.

The anatomy of my automatic developer can be divided, for the sake of discussion, into three principal subject matter areas, namely, (1) the area of the abovediscussed elevator and its drive machinery, involving a consideration of mechanical and structural features for the most part; (2) an area encompassing the X-ray developing capacity of the device, involving consideration of procedural, chemical, and plumbing sub-areas, as will later be seen; and (3) an area relating to the automatic control system for the developer, the subsequent description of which will largely involve electric circuitry and related sub-areas. The foregoing classification does not neatly slice the whole pie into separate pieces, each distinct from the other, but loosely isolates certain easily classifiable categories of subject matter which diverge from center areas of obvious contradistinction to outlying fringes which blend into each other to form twilight zones of overlap.

To this point, only the first of the above-listed categories of subject matter (elevator 18 and its drive mechanism) has been discussed. Proceeding now to the second, or X-ray developing category, attention is first directed to FIGURES 1, 2 and 3, which show the automatic developer in full-dress setup, complete with the necessary solution tanks for use in the development of dental X-ray plates. As previously indicated, FIGURES 1 III 23 2 and 3 show the two travel position extremes of elevator 18. The purpose served by the elevator in traveling between these two extremes is to advance a rack, or basket, 85, of dental X-ray plates from one liquid bath 33 to another 81, forwardly positioned thereof as shown. In this connection, FIGURE 2 shows elevator 18 at its lower terminus and rack 85 in liquid bath 33 at the proper depth to completely immerse X-ray plates carried thereby. The structure of rack 85, and its means of support by the elevator will later be described in detail. For present purposes, it is only necessary to observe that elevator 18 is so disposed at its lower terminus to support a rack of X-ray plates at the proper immersion depth within a liquid bath positioned as shown in the drawings.

While particulars of its specific accomplishment will be saved for later disclosure, it will be helpful to presently note that elevator 18 carries rack 85 with it in its upward travel to the position illustrated by FIGURE 3. As the elevator approaches its highest point, rack 85 is urged forwardly relative thereto, and later, as the elevator descends, the rack moves still further in the forward direction until it is directly over the liquid bath just ahead of the one last evacuated as the elevator approaches its lower terminus. From here, elevator 18 gently rides into its lower terminal position, and, in so doing, eases the rack into said liquid bath for its predetermined residence time therein. FIGURES 2 and 3 partially illustrate this sequence of operations in that FIGURE 2 shows the starting point of the elevator trip with basket 85 immersed in liquid bath 83, and FIGURE 3 shows the upper limit of the trip, at which point the basket has started its forward movement relative to the elevator. Upon descent of the elevator from the FIGURE 3 position, basket 85 will continue its forward movement until it is directly above liquid bath 81, into which it will settle as the elevator moves to rest at its lower terminus.

Returning now to the description of the drawings, there are four liquid bath, as FIGURES 1, 2 and 3 show, within housing 2, supported on a horizontal level and arranged in consistent alignment with the longitudinal direction of the housing and transversely centered therewithin. These baths, two of which have previously been christened, are designated, from left to right, as they appear on each of the aforesaid figures, as 83, 81, 79 and 77, and they constitute bodies of X-ray developer solution, firs-t rinse water, fix solution, and second rinse water, respectively. The progress of the X-ray plates through these baths is in the order just set forth, that is, the plates are first immersed in the developer solution, then in the first rinse water, then in the fix solution, and finally in the second rinse water, after which they are removed from the water and suspended in a stream of warm air to dry. The immersion time in each of the liquid baths is automatically regulated for consistency with good X-ray developing practice, and the drying time is likewise regulated, all in a manner hereinafter described in detail.

The reason for the herein-taught program of alternating periods of elevator movement and rest, as will now be clear, is to permit properly timed immersion of the X-ray plates in each of the baths and to effectuate the timely conveyance of the plates from each of the baths to the next succeeding one by one round trip of the elevator to its upper limit of travel and back. The exact manner in which the round trip of the elevator succeeds in conveying the X-ray plates from one bath to the next remains to be explained, although the drawings probably make this clear, particularly when considered in the light of the foregoing disclosure. i

Liquid baths 83, 81, 79 and 77 are confined in vessels, or tanks, later to be described in detail, and the tanks are supported on a platform 75, which is horizontally positioned within housing 2. at an elevation sufiicient to clear gear motor 99 and all of the elevator drive mechanism thereunder (which includes all of the mechanism except side rods 48, 50, 52 and 54, and portions of the ends of shaft 64) except the upper forward corner of oscillating arm 88 at its position of highest movement during operation of the mechanism. However, to prevent jamming of this corner of the oscillating arm with the under surface of platform 75, a slotted opening, which is shown at a and hereinafter referred to as slot 75a, is cut through the platform to give the necessary clearance for unhindered travel of the arm. Slot 75a, asthe drawings show, runs in the same direction as the longitudinal dimension of platform 75, is transversely centrally positioned in the platform, and is situated directly over the forwardly extending portion of said oscillating arm.

As will later appear, platform 75 is readily removable from housing 2, and slot 75a serves the purpose, in addition to that noted, of providing a finger-hold for grasp of the platform when inserting it into the housing or removing it therefrom for repair or disassembly of the apparatus. Another opening is provided in the platform at 75b to permit upward protrusion of an elongated toggle switch lever 73, the function of which will subsequently be discussed, therethrough. The opening in platform 75 through which toggle switch lever 73 protrudes will be hereinafter referred to as rectangular opening 75b.

Platform 75 is of wooden construction, although it could be made of any other suitable material, such as one of the corrosion-resistant materials of the class of preferred materials of construction for the parts of'elevator 18, its drive system and other parts of the subject apparatus setforth above. The property of corrosion-resistance is as important in platform 75 as anywhere else in the apparatus, for the reasons previously advanced in support of its desirability in parts fabricating materials. The platform is of generally rectangular shape, long enough to fit snugly, but not bindingly, in longitudinal alignment within housing 2, but sufficiently narrow to permit its insertion into, and removal from, its position in the housing between long tie straps 28 and 30 defining the upper longitudinal edges of elevator 18.

The maximum permissible width of platform 75 is, as a practical matter, determined 'by the distance between tie straps 28 and 33, since, as the drawings make clear, it is necessary because of the internal arrangement of parts within housing 2, to take the route between those tie straps when moving the platform into or out of the housing. The exaggerated height of toggle switch lever 73, which suits it for a purpose later to be disclosed, and the proximity of that member to the forward portion of elevator 18, makes it somewhat difficult to maneuver platform 75 into and out of housing 2, but with a little practice, this can easily be accomplished when elevator 18 is in its upper, or FIGURE 3 position. To briefly explain, the platform is moved into position within hOuSing 2 by guiding its forward end between long tie straps 28 and 30 and under short tie strap 32 (which defines the upper frontedge of the elevator) and, at the same time, taking care to see that toggle switch lever 73 threads into rectangular opening 75b near its forward end, after which the platform is moved ahead until its rear edge clears short tie strap 34, at the top rear of the elevator. From this point on it is a simple matter to jockey the platform into its proper place of rest in housing 2.

Removal of platform 75 from the housing poses even less of a problam than its insertion therein, and is accomplished by simply reversing, both chronologically and directionally, the steps of the abovedescribed procedure. Platform 75 is supported within housing 2 by means of two wooden strips 71 and 69, aifixed to the facing surfaces of end walls 10 and 12, respectively, of the housing. These strips hold up the ends of platform 75 in the manner shown in the drawings, and they are fastened by nail means (not shown) to their respective backing walls, each at the proper elevation and in the proper directional alignment to support the platform at an effectively operable height and positional orientation within housing 2. Each of the wooden strips is transversely centered on its backing I 7 wall, by which is meant centrally located width-wise of the wall. Strip 69 (at the rear of housing 2) is about as long as platform 75 is wide, so that its ends do not protrude from under the platform when it is at rest thereon as shown in FIGURES 1 and 5.

Wooden strip 71, on the front wall of the housing (end wall 10) is recessed along its top to a depth roughly equal to the thickness of platform 75, and for a distance slightly greater than the platforms width, to form a mating hollow into which the end of the platform can fit in snug but nonbinding relationship. This nesting interfit between the platform end and the recessed support strip is well illustrated in the drawings, and particularly in FIG- URE 1, wherein the non-recessed portions at the upper ends of the latter are shown at 71a and 71b, respectively. The principal reason for nesting one end of platform 75 in the described manner is to secure it against sidewise migration from its central position within housing 2, which, as will subsequently be apparent, would militate against proper functioning of the developer apparatus. Without some sort of security against lateral movement of the platform, such movement could take place within the limits of the four upright slide members of elevator 18. The latter members, as the drawings show, and will be appreciated from an understanding of the arrangement and juxtaposition of parts within housing 2, are situated adjacent the lateral edges of platform 75, two to each side of the platform and slightly outboard thereof. There is, of course, no possibility of any of side rods 48, 50, 52 and 5'4 jamming against platform 75 at any phase of their movement during Operation of the elevator drive mechanism, because of the spaces provided between the side rods and the lateral edges .of the platform.

Directing attention now to liquid baths 8.3, 81, 79 and 77, which comprise, as previously indicated, bodies of developer solution, first rinse water, fix solution and second rinse water, respectively, it is first noted that there is nothing critical about the chemical compositions of the developer and fix solutions. In this connection, any developer or fix solution presently employed for dental X- ray developing processes is suitable for present purposes. For the foregoing reason, plus the commonly known fact that the chemistry of such solutions is either familiar to those skilled in the art or readily accessible to them in publications of which they are aware, and the further fact that the solution ingredients are commercially available to any-one with the purchase price, the solutions will be identified herein only by popular name and not by chemical composition.

Liquid baths 83, 81, 79 and 77 are confined in three plexiglass tanks, 67, 65 and 63, so shaped, sized and assembled atop platform 75 as to define separate zones of confinement for the baths. The confines of each zone of containment are elongate and trough-like, and the zones run, in parallel adjacency, transversely across platform 75 for most of its width. Developer solution 83, constituting the bath to the rear of the housing, or to the left of the line of baths as pictured in the drawings, is contained in plexiglass tank 67, a rectangular, open-topped vessel fabricated of precut wall and bottom sections of ..plexiglass, which are glued together at their meeting edges to form leakproof seams of sufficient rigidity to hold the vessel together. Tank 67 forms the boundaries of one of the above-indicated liquid bath zones. The boundaries of the other three zones are formed by tanks 65 and 63, which are so sized and shaped as to permit interfit of the latter into the former in the below-described manner.

Tank 65 is an open-topped vessel, formed of plexiglass wall and bottom sections in the same manner as is tank 67. However, it is sufficiently larger than the latter tank to internally accommodate three, rather than only one, of the liquid bath zones, as the drawings, and particularly FIGURE 1, Well illustrate. In addition to being bigger than tank 67, tank 65 differs therefrom in certain internal particulars, discussed below, and in the extensions of its side walls a short distance past its front wall to form a pair of wing- like members 59 and 61, respectively, which flank a small area to its immediate front. Tank 63 is the smallest of the three solution-containing vessels, and, like the other two is open-topped and of rectangular shape. The internal width of tank 63 is substantially the same as that of tank 67, but its length is sufliciently shorter than that of the latter vessel to permit its perpendicular endwise insertion in tank 65. The tolerances between the applicable dimensions of tanks 63 and 65 are such as to permit insertion of the former into the other in the described manner with easily sliding clearance between the ends of the one and the inner sides of the latter.

As the drawings show, plexiglass tank 63, by virtue of its interfit relationship with tank 65, and with the aid of certain cooperating parts within the latter, later to be described, internests laterally across and longitudinally centrally within tank 65. The longitudinal axis of tank 65 runs parallel to that of platform 75, and it is thus apparent that the described assembly of tanks yields three partitioned areas. These areas correspond to the three liquid bath zones of previous reference, the middle area, or zone, consisting of the space within tank 63 and the other two comprising the spaces between its side walls and the end Walls of tank 65, within the latter tank, respectively. These three partitioned areas, and that within plexiglass tank 67, are of roughly, but not exactly, the same size and shape, and in each instance adequately capacious to receive rack and permit proper liquid immersion of its load of X-ray plates for purposes of this invention.

When smaller tank 63 is nested within larger tank 65 in the abovexiescribed manner, it does not rest on the bottom surface of the latter vessel, but is suspended a slight distance thereabove, thus providing open communication for liquid circulation between rinse water bath zones 81 and 79, which, as previously indicated, occupy the spaces within tank 65 on either side of tank 63. It will, of course, by now be apparent that fix bath zone 79 comprises the area within tank 63. It will also be apparent that the first rinse water in liquid bath zone 81 is not a separate body of liquid from the second rinse Water in zone 77, but that, instead, the two form a common body of Water in outerly surrounding contact with the side walls and bottom of tank 63, the advantages of which are at least two-fold, as will hereinafter be explained.

It should be noted, at this juncture, that although no plumbing system for the bath tanks is shown on the drawings, and the pictured apparatus will function satisfactorily without such, the preferred commercial form of my apparatus incorporates Water flow rate and temperature controls of such character as to permit the constant flow of rinse water, maintained at the proper temperature, through its two rinse water zones when so desired. Controls of the indicated type can be easily installed as accessories to, or for close cooperation with, the liquid bath assembly of the automatic developer by one skilled in the art with the present teachings before him. To illustrate, a water valve of the type used in shower baths can be plumbed into a hot and cold water input system for the baths to maintain the inflowing water at a preset temperature.

Drain means are preferably installed and employed in the water rinse system of the developer where the inflow water controls of the suggested, or other suitable, type are furnished. Such drain means makes it possible to maintain a constant flow of water, at the desired temperature, through the water bath zones. As previously indicated, and will hereinafter be discussed in greater detail, liquid bath temperature is a factor of some importance in X-ray developing technology. It should perhaps be pointed out that the installation and use of drain means accessory to, or in conjunction with, the rinse water facility of my automatic developer burdens the ingenuity of one skilled in the art no more, and possibly even less, than installation and use of the water input control means of above note.

For the indicated reasons, to wit, lack of criticality to functioning capability of my automatic developer of a water control system and the ready capability of one skilled in the art to install such a system, no further discussion of the plumbing, or other, particulars thereof will here be attempted. In any event, whether or not accessory water flow and temperature controls (by which is meant controls more or less a part of the developer apparatus, or closely allied therewith from the structural standpoint) are utilized, a prime advantage of the illustrated tank configuration is that it readily permits withdrawal of the developer and fix solution tanks (67 and 73) therefrom for emptying, cleaning, loading with fresh solution, etc., purposes, with minimal disturbance of either the rinse water or its containing vessel (tank 65). A further advantage is that it helps to maintain a uniform temperature (which, as those skilled in the art will appreciate, is desirable) throughout the whole liquid bath setup in that it permits the free circulation of temperature-regulated water around the sides and bottom of the fix solution tank (63) and in the adjacent vicinity of the developer solution tank (67).

Where flow and temperature controls are incorporated in, or used in close conjunction with, the water bath system, the foregoing advantages of the tank configuration are enhanced, since the presence of the resulting plumbing hardware makes it of even greater advantage to be able to remove the developer and fix solution tanks without disturbing the water system, and the added control features insure better maintenance of desired water temperatures and, hence, better temperature control throughout the whole bath assembly. Additionally, the incorporation of water flow and temperature controls, including drainage means, into the water rinse facility, permits the continuous removal of impure water from the water bath tank since it can be continuously replaced with inflowing fresh water.

The fix solution tank (63) is guided into, and maintained at, its longitudinally central location within water tank 65 by the presence of four plexiglass stop blocks of equal size, 57, 55, '53 and 51. These stop blocks are fixedly secured by glue means in the side dihedral corners of tank 65, and so positioned as to define the four corners of the space occupied by the bottom of tank 63 when it is properly berthed for purposes of this invention. Tank 63 is supported at its ends, within larger tank 65, by two strips of plexiglass, 49 and 47, fixedly secured by glue means in the dihedral corners of tank 65 occupied by the aforesaid stop blocks, strip 49 running for most of the distance between stop blocks 57 and 55, and strip 47 similarly occupying the space between stop blocks 53 and 51, which pairs of stop blocks are, as the drawings illustrate, situated transversely opposite each other in the larger tank. Plexiglass strips 49 and 47 do not rise as high as stop blocks 57, 55, 53 and 51, and this permits the latter members to serve as defining limits within which to guide tank 63 to its mooring position within tank 65, and thereafter physically restrain the smaller tank against movement out of that position. Tank 63 is sulficiently lower than tanks 65 or 67 (which latter two are, as the drawings, illustrate, of equal height) to render its upper edges coplanar with the upper edges of tank 65 when it is inserted therein. The purpose of strips 49 and 47 is, as will be evident, to support the outer surface of the bottom of tank 63 a short distance above the floor of tank 65 and thus provide open communication between water rinse bath zones 81 and 77.

FIGURES 2 and 3 show that there are four vertical channels, 14cm, 14ab, Mac and 14nd, within the 14a network of guideways separating the group 14 arrangement of plexiglass section pieces on side wall 6. Those drawings further show that the said vertical channels are in substantial alignment with the longitudinal bisectors of liquid bath zones 83, 81, 79 and 77, respectively. Since, as previously disclosed, guideway network 14a is matched by mirror-image network 16a defined by the group of plexiglass sections on side wall 8, it follows that the four above-identified vertical channels have four counterparts in the 16a network of guideways, and that these are likewise in line with the longitudinal bisectors of the four liquid bath zones, respectively. While the latter four channels (16a network) are not shown anywhere on the drawings, such a showing is unnecessary in view of the fact that their locations have been given and it has been disclosed that they are mirror-image reflections of channels 14ml, 1412b, Mac and 14ad, which are fully described and shown.

It is important that the alignment between the four above-described pairs of oppositely facing vertical channels and the longitudinal bisectors of the four liquid bath zones, respectively, as well as the lateral spacing between the channels and liquid bath zone areas, be preserved, for reasons later appearing. To effectuate this purpose, by curbing the possibility of either sidewise or forward migration of the liquid-containing tanks during operation of the automtic developer, three sections of angle aluminum, 106, 168 and 110, respectively, are fastened to platform by nail means, only partially shown, at strategically suitable locations. Angle section is fastened transversely across platform 75, with one flange flush against its upper surface and pointing forwardly toward the front of housing 2, and the other flange extending outwardly, as shown particularly well in FIGURES 2 and 3, to provide a barrier against forward movement of tank 65 and help position the forward edge of the tank for proper alignment of the liquid bath zone bisectors and the aboveidentified vertical channels in guideway network systems 14a and 16a, respectively. As FIGURE 1 shows, the length of angle aluminum section 110* is such as to substantially fill the narrow space between the wing- like sections 61 and 59 of the side walls of tank 65 (hereinafter called wings 61 and 59) yet leave sufficient clearance at its ends to avoid jamming.

Wings 61 and 59 are helpful aids to the proper seating of tank 65 on platform 75. This is particularly important in cases where plumbing fixtures for a water flow control system are connected to the tank, since the tank must then, as a general rule, stay oriented in the same direction to assure proper hookup with outside plumbing lines or facilities. Wings 61 and 59 provide ready means for effectuating this tank orientation upon initial installation, or thereafter upon reinstallation of the tank after removal for cleaning, or other, purposes. In this connection, it will be apparent that the liquid tanks of the drawings are properly positioned in the automatic developer only when wings 61 and 59 extend forwardly toward the front of the housing, since, otherwise, the wings would force the developer solution tank out of its proper position of alignment with the above-indicated vertical channels in guideway systems 14a and 16a, and thereby render the appara tus inoperative for reasons later made clear.

Angle aluminum sections 106 and 108 are fastened along the side edges of platform 75, with one flange of each flat against the under side of the platform and the other flange extending upwardly flush against a side edge thereof. The two sections are of equal length and each stretches for most, but not all, of the distance between the position of transverse aluminum section 110 on, and the rear end of, the platform. Sections 106 and 108 are made from angle aluminum of such size that the upstanding flange of each projects above the upper surface of platform 75 for about half of its height to form a side curb of suflicient elevation to prevent sidewise migration of the liquid bath tanks therebeyond during operation of the automatic developer.

It has been explained above that the illustrated embodiment of my invention functions by employing an elevator, and drive mechanism therefor, to convey, in a manner not yet made completely clear, exposed dental X-ray plates from bath to bath through a series of liquid bath zones confined in tanks supported atop platform 75, the liquid baths comprising conventional developer and fix solutions and water rinses, and thereby develop the exposed X-ray plates automatically. It has also been pointed out that the X-ray plates are conveyed through the automatic developing procedure in a rack supported throughout, in a manner hereinafter described, by the aforesaid elevator. Rack 85 is a basket-like structure of generally rectangular cross section and elongated form, so dimensioned as to fit easily into each of the aforesaid liquid zones with sufficient room to spare to permit unhindered circulation of the liquid therearound during operation of the apparatus.

The rack is made of plexiglass (although it can be of any suitable material inert to the liquid bath materials into which it is dipped in the practice of the present invention) structural elements fastened together by glue means so as to form an open topped-carrier of generally hollowed-out interior, but having evenly spaced ribs, exemplarily illustrated at i on the drawings (all ribs being so designated due to their similarity) encircling its inner surfaces. The ribs i divide the interior of tank 35 into a plurality of square, transversely parallel slots, as exemplified at 85a, all such slots being so designated because their similarity, of predetermined size to admit dental X-ray plates, one toeach slot, in loosely nesting relationship. The outer bottom of rack 85 has two longitudinal recesses 85b and 85c running for its full length, said recesses being spaced equidistantly from the center line of the bottom and penetrating as far as slots 85a. Longitudinal recesses 85a and 850 thus provide openings in the bottom of each slot 85a to permit free circulation of the surrounding liquid through the rack and into contact with the X-ray plates when carrier and plates are immersed in one of the aforesaid liquid baths.

Although rack 85, as drawn, includes only fifteen of the SSA slots, twenty such slots are required to hold one complete set of dental X-ray plates. The drawings are only intended to illustrate the carrier structure, however, and it is felt to accomplish this better as it stands than it would if slots were crowded into the space now occupied by 15, since such crowding would detract from the presently achieved clarity of illustration. Furthermore, the depicted type of carrier is only one of many suitable alternatives within the scope of my invention. For example, the carrier could have a wire screen, such as a stainless steel screen, bottom, sides, or both, and this might even be superior to the rack 85 construction in that it would permit freer circulation of liquid around the X-ray plates during operation of my automatic developer. Another alternative is the substitution of supported clips, which in turn support individual X-ray plates, for the above-described rackor screen-type carrier. The clip arrangement permits complete freedom of liquid circulation around the X-ray plates, since there is no hardware structure to the block or hinder it.

Rack 85 is suspended from a round support rod 112, by hardware means hereinafter described, of sufi'icient length to extend across housing 2 and into transversely opposite grooves, or channels in guideway networks 14a and 16a on housing side walls 6 and 8, respectively, to a sufiicient depth to ride freely, without binding, therein, when urged to do so and maintain at the horizontal during such movement. The rack is suspended directly under support rod 112, and in transverse symmetry about its longitudinal, and vertical, bisector, as the drawings well illustrate. Support rod 112 is metallic, preferably being made of a corrosion-resistant metal such as stainless steel, for reasons previously given in advancing the cause of corrosion-resistance in materials of construction for other parts of my automatic developer.

Rack 85 is suspended under, and locked to, support rod 112 by means of three strips of metal, preferably a corrosion-resistant metal such as stainless steel, 114, 116 and 118, respectively, bent and apertured in the hereinafter indicated manner to suit them for their individual purposes. The three strips are of equal width, this being slightly less than half the width of the rack 85, and two of them, 116 and 118, are of equal size and shape, whereas the third, 114 is substantially different therefrom in both respects. Similar strips 116 and 118 are L-shaped and much smaller than strip 114, which latter consists of a relatively long center span, substantially equal in distance to the length of rack 85, terminating at each end in a upward bend, after which the strip rises to the same height at each end of the center span and doubles sharply back upon itself to descend adjacently and parallely to its ascending portion and then to a point substantially below support rod 112, whereat it is bent at a 90 angle to form an inturncd flange directed toward the other descending end of the strip.

The long center span, ascending the descending end portions, and inturned end flanges of metal strip 114 are shown at 1', k, l and m, respectively, on the drawings, and particularly FIGURE 9. The L-shaped strips 116 and 118 are each fastened with a downwardly depending leg flush against, and in lateral edge alignment with, the outturned surface of one of end sections k and l of metal strip 114 by rivet means, as shown at 120 and 122, respectively, on the drawings, and an opposite leg extending outwardly away from the end of strip 114 and on the same plane as long center span j of that member.

As will be apparent from the foregoing discussion of the involved parts, and as clearly depicted by the drawings, long center span and the two outwardly extending legs of L-shaped strips 116 and 118 form a substantially continuous bed, interrupted by upstanding partitions near 5 each end comprising the ascending and'descending doubled back sections of metal strip 114 forming the upper portions of end sections k and l of that member, the aforesaid partitions being shown at ka and la on the drawings. Hereinafter this continuous bed will be referred to as strip bed 124.

It has already been established that elevator 18 is automatically controlled to make periodic trips to its high point of travel and return, and that it conveys rack -85 with a load of X-ray plates from a liquid bath zone to the next forwardly adjacent zone each time it makes such a round trip. Support rod 112 rides on top of the elevator, as the latter moves up and down through its vertical itinerary, carrying rack 85, which is harnessed thereto by means not yet fully described, with it as it goes. The weight of the rod, rack and connecting harness means is, at all times, borne directly by parallel tie straps 28 and 311 at the top of the elevator, across which said rod lies in perpendicular relationship with its ends in oppositely posiitioned grooves, or guideways, of guideway network systems 14a and In this connection, and so that there will be no misunderstanding, the individual guideways of guideway network systems 14a and 16:! are referred to herein variously as guideways, grooves, or channels, making those terms synonymous as applied. Of the foregoing terms, guideways is perhaps the preferred one, since, as will presently appear, it is connotative of the purpose served by the narrow spaces or passageways thereby denoted.

Returning now to the discussion of support rod 112 and its travel habits in the illustrated apparatus of my invention, the rod at all times, whether riding on the elevator or merely lying across it in its position of rest between trips, has each end captive, as previously indicated, in one of the guideways of the 14:1 and 16a guideway network systems. This channelure confinement of the ends of the support rod maintains the rod in perpendicularly transverse position within housing 2 at all times since, as has already been made clear, the guideways of residence of its two ends at any given moment are directly opposite each other on the side walls of the housing, and the guideway networks of which they form a part, 14a and 16a, respectively, are mirror-image topographical duplicates of one another, thus assuring identical travel of the two ends of the rod, in their separate but parallel planes of confinement when induced to movement by the time-table travels of elevator 13. 'Since support rod 112 is mounted on the elevator in the above-described piggyback fashion, the latter obviously carries the rod through the same vertical distances that it, itself, traverses in the course of its travels within housing 2. At the same time that the rod is riding vertically on elevator 18, however, it is moving forwardly within the housing, being guided in that direction by the sliding progresson of its two ends along charted passageways within the respectively imprisoning guideway network systems, the charted passageways being so laid out as to gently advance the rod ends the distance from one liquid bath zone to the next in line during one round trip of the rod on the elevator. The threading of the ends of support rod 112 through the charted passageways will hereinafter be followed step by step. For the present, it is only necessary to understand in a general way the means by which support rod 112 is steered forwardly within housing 2, thereby advancing rack 85 and its load of X-ray plates from one bath to the next during each lift and descent of the elevator.

Continuing now with the description of the hardware connecting rack 85 to support rod 112, attention is again directed to bent metal strips 114, 116, and 118, which are fastened together in the above-described fashion to form an elongated bed of strip metal, 124 with parallely upstanding partitions ka and la, intermediate its ends, and depending strip sections, substantially coplanar With partitions ka and la and hereinafter referred to as depending strips kb and lb, respectively, of equal length with inturned flanges m and n at their respective lower ends. The

space between depending strips kb and lb is sufiicient to accommodate the length of rack 85 and the intended purpose of flanges m and n on the depending strips is to grab and hold the ends of rack 85 in the manner depicted in FIGURE 9. To briefly explain, the ends of rack 85 have accommodating slots for the edges of inturned flanges m and n of depending strips kb and lb, respectively, the slots being so positioned as to assure level hang of the rack when supported in the described manner. To suspend'the rack in the illustrate-d fashion, it is merely necessary to pass the inturned flanges of depending strips kb and lb into their mating slots on the ends of the rack, by one means or another, and then, if necessary, slide the fianges and rack relative to each other to transversely center metal strip bed 124 and said rack on the same vertical plane. The natural resiliency of any suitable material of construction for depending strips icb and lb, many ex amples of which will be obvious to those skilled in the art, permits the snapping together of the inturned flanges of those strips and bracket 85 in the described manner with no difiiculty.

Hereinafter, for the sake of simplicity, the whole strip assembly comprising metal strip bed 124 and all parts appurtenant thereto as heretofore described and illustrated, will be referred to as harness 126. It has previouslybeen explained that support rod 112 stretches transversely across, and rides on, tie straps 28 and '30 at the top of elevator 18. While this is in a sense true, it does not quite tell the whole story since, as will now explained, and is illustrated in the drawings, the support rod is cradled for a good part of its length on metal strip bed 124, and the length of the strip bed exceeds the transverse distance between parallel tie straps 28 and which support the whole rack-harness-rod assembly. The rackharness-rod assembly is substantially symmetrical about the plane of transverse bisection of support rod 112 which means that the ends of metal strip bed 124 extend suificiently far in each direction to come between the support rod and tie straps 28 and 30, respectively, at the points 2d of support of the rod on those members, as illustrated in the drawings, and particularly FIGURE 1. As the drawings also illustrate, support rod 112 is transversely cen trally positioned on metal strip bed 124 so that its longitudinal axis lied directly over that of the bed.

The above-described, and drawing-illustrated, support rod-harness configuration is designed to assure good balance and hang of the supported rack, and the extension of the ends of metal strip 124 to over-reaching positional relationship with respect to the aforesaid tie straps precludes the possibility of support rod roll on the tie straps, and consequent unbalancing of the rack from its proper position of hang. The support rod passes through aligned holes in upstanding partitions ka and la on metal strip bed 124, the holes being so sized and located as to receive the rod in tight friction fitting relationship and hold it in its proper position of cradle atop the strip bed, as illustrated in the drawings, and particularly FIGURE 9. While the described friction fit of the support rod in the holes in the upstanding partitions ka and la on harness 126 is perfectly adequate for the purpose, the strength and tightness of the assembly can be enhanced by spot-welding the rod to the aforesaid partitions where it passes through the holes therein.

An explanation of the manner in which elevator 18 functions during operation of the drawing-illustrated embodiment of my invention has been given, although neither the automatic control system for the elevator nor its manner of operation have, as yet, been described or discussed in detail. This is consistent with the dilineative approach used herein, and explained above, in which the subject matter of my invention has been divided into three general categories for separate treatment and discussion. Further in line with this approach, I will now proceed to describe, for illustrative purposes, the step-byptep progress of a rack load of X-ray plates through the automatic developing process of my invention as specifically carried out, in present contemplation, by the pictured embodiment of the automatic developer, again omitting discussion of the automatic control system of the developer.

Assuming the automatic developer is set up, plugged into a source of electrical power, and in all respects ready for use, it is normally put to use by first manually loading it with a rack of exposed X-ray plates, this being accomplished by inserting the plate-loaded rack, harnessed to support rod 112 in the above-described manner, into the rear end of housing 2 in the below-described manner. Elevator 18 should be at rest at its lower terminus, as shown in FIGURE 2, when the rack of X-ray plates is inserted into the housing. The insertion of the rack assembly is easily accomplished, as the drawings make clear, by lowering the two ends of the support rod into wide-mouthed entrance ways, shown at More and 16m: on the drawings, and hereinafter designated in that fashion,

'to the guideway network systems 14a and 16a on the two side walls of the housing. The rack assembly is inserted rack down and with support rod 112 substantially horizontal. From wide-mouth entranceways l iae and 16ae the support rod is slipped down through twin angled guideways in mirror-image relationship on the opposite side walls of the housing, one such being illustrated in FIGURES 2 and 3, to connecting vertical channels pointing, on opposite sides of the housing, towards the longi tudinal axis of plexiglass tank 67 filled to the proper level with developer solution.

I One of the aforesaid vertical channels is shown at Hall on FIGURES 2 and 3, its mirror-image counterpart on the opposite side of the housing not being visible in any figure of the drawings. As previously explained, however, the location, size, andother particulars of the-latter channel are readily comprehensible from the pictorial illustration of channel 14am and the foregoing description of guideway networks 14a and 16a, the latter of which it 25 vertical channels until the support structure for the assembly comes to rest on the straps 28 and 30 of elevator 1.8 in the position shown in FIGURE 2. At this point, the rack and its load of X-ray plates is fully immersed in the developer solution bath in tank 67 and the chemical plate developing process now begins. While the X-ray plates in rack 85 have not always heretofore been expressly referred to as exposed plates, it will be understood, of course, that they have obviously been previously exposed.

After the rack load of X-ray plates has been lowered into the developer solution in the described manner, the automatic developer takes over and automatically performs subsequent steps until the plates have been fully processed and dried. Without going into any further control detail at this time, the whole procedure is initiated by the flip of a panel switch which activates the control system for regulating the immersion times of the plates in the various liquid baths, etc. Returning now to the description of the mechanics of the developing process itself, after the rack of X-ray plates has remained in the developer solution for the properly predetermined period of time, the drive motor for elevator 18 is automatically activated, causing the elevator to rise and lift the rack assembly with it. As the assembly ascends with the elevator, the ends of support rod 112 ride upwardly in channels 14cm and its counterpart on the opposite side of the housing to the lower edges of counterpart sections of plexiglass sections in groups 14 and 16 of the channel-forming plexiglass sections on opposite side walls of the housing respectively, which lower edges slant upwardly and forwardly to a high point at which each levels out into a shallow curve, the plexiglass section in group 14 being shown at 128 in the drawings, and its counterpart section in group 16 at 130. Hereinafter, for the sake of simplicity, the movement of only the end of support rod 112 traveling in the 14a guideway network system, shown topographically in FIGURES 2 and 3, will be described, although it is to be understood that the other end of the support rod is similarly moving through a mirror-image maze of passageways on the opposite wall of the housing.

As the elevator continues to ascend beyond the point at which the appropriate end of support rod 112 has contacted the upwardly slanting under edge of plexiglass section 128, that end of the rod rides upwardly but is urged in the forward direction, or to the right as seen on FIG- URES 2 and 3, by its moving contact with said slanting edge, this movement being accelerated as the rod end rounds the curved section at the upper end of the edge. The slanting and curving lower edge of plexiglass section piece 123 is so contoured, the piece is so positionally oriented on housing side wall 6, and the upper travel limit of elevator 18 is so fixed that coincidentally the end of support rod 112 in contact with, and being deflected by, said lower edge as the elevator ascends, moves along that edge to the far end of its curved portion, the curved portion being shown at 128:: on FIGURE 2 and hereinafter designated as curving edge 128a, and the elevator approaches and reaches its zenith. Thus, both the end of the support rod and the elevator arrive at their upper destinations concurrently, this joint arrival being illustrated in FIGURE 3 which shows the positions of those two parts at exactly that time.

After reaching its FIGURE 3 position, elevator 18 begins to descend, as a result of which support rod 112 rides straight down on top of elevator tie straps 28 and 3-0 until its appropriately oriented end contacts a downwardly and forwardly sloping upper edge 132a of a plexiglass section piece 132, one of a horizontal line of similarly-shaped section pieces within the group 14 display of plexiglas sections on housing side wall 6. The elevator continues its descent after the support rod makes its contact with sloping edge 132a as described, and this causes the rod to ride forwardly on tie straps 28 and 30 at the top of the elevator, being urged to do so by the cam-like interaction between the sloping edge and the support rod end. The end of the support rod follows edge 132a forwardly to where it intercepts a defining boundary of the vertical channel 14x11), which channel, as previously indicated, is directed vertically downwardly toward the middle of the first water rinse bath 81, as shown in FIGURES 2. and 3. The intercepted boundary of channel ldab is, additionally, one of the edges of plexiglass section piece 132, a pentagonally-shaped piece, as the drawings show. Its point of interception by sloping edge 13211 is shown at 13% in FIGURES 2 and 3, and will hereinafter be referred to as interception point 132]).

As the elevator continues to descend, the end of support rod 112 in contact with sloping edge 132a passes interception point 132b, after which the end of the rod follows channel ldab vertically downwardly to a lower terminal position therein. At that position, the rack assembly is at rest with the rack suspended within first water rinse bath 81 to the same depth as figure shows it immersed in developer solution 83. Elevator 18 has simply completed a round trip to its apogee and back, and has thus come to rest at the same position as that shown in FIGURE 2. It will remain at rest until automatically forced by its drive system, after a predetermined rinse time for the X-ray plates in zone 81, to repeat the round trip to its upper terminus and back. The rack of X-ray plates has been circuitously conveyed by the elevator ride from immersion in developer solution 83 to immersion in first rinse water bath 81.

Enough has now been given by way of description, it is believed, to fully reveal the nature and physical particulars of the tortuous paths of progression of each end of support rod 112 through the 14a and 16a guideway channels, respectively, especially when FIGURES 2 and 3 of the drawings, which map the Ma paths, are conjunctively resorted to. While it will be obvious to one skilled in the art, it is nevertheless pointed out that the invention is not limited to the particular guideway layout of the drawings, and that any system of conveying support rod 112, or its equivalent, through a path leading from an immersion station for one liquid bath to a similar immersion station over another liquid bath incrementally advanced from the first, falls within the structural and functional scope of the invention. All that is necessary in such a guideway maze is that deflecting barriers be so placed as to effect cam-like guidance of the support rod ends in the proper directions to steer them through passageways provided therefor within the maze.

Rack 85, with its load of X-ray plates, remains immersed in the first rinse water bath for the properly predetermined period of time in accordance with the programrned instructions to the automatic control system for the elevator drive mechanism. The length of the water rinse residence time, as is also true of the residence times in the other liquid baths of the X-ray developing process, has no relevancy insofar as the present discussion is concerned, since it has nothing to do with the critical structural or functional aspects of my automati developer or its method of operation, and the developer will operate effectively regardless of the lengths of any of the applicable immersion times. For this reason, plus the fact that those skilled in the art are well aware of, or can easily ascertain, proper immersion times for particular X-ray developing baths, no further comment on that point is here felt necessary. Suffice it to say that once having ascertained the proper or desired immersion times for the involved liquid bath, it is a simple matter to program these times into the automatic control system of my invention by known timing, or equivalent, techniques, as will appear from the description of my control system to follow.

Turning now to the description of the manipulative steps performed by my automatic developer in processing a batch of exposed X-ray plates, elevator 18 is again induced to action after expiration of the aforesaid residence time of rack 85 in the first rinse water bath, as a result of which it repeats the above-described trip to its upper limit of travel and back, concurrently conveying support rod 112, and its suspended rack load, through a circuitous path of travel identical to that just described, in which the rack assembly was conveyed from the developer solution bath to the first rinse water bath, except removed one bath-unit increment forwardly thereof. By bath-unit increment, as that term is here employed, is meant the distance from left to right through guideway system 14a, as viewed in FIGURE 2 or 3, representing the space between the longitudinal bisector of one of the liquid bath zones to that of the one adjacently to its right, in this case, the space between vertical channel 14ab and vertical channel Mac.

It is only necessary to compare the passageway followed by the here-involved end of support rod 112 from its low position in channel 14m to its low position in channel 1411b with the passageway through the next bath unit increment from the 1441b to the 14cc vertical channel, to see that the routes are identical, with equivalently designed and internally positioned guide barriers. For example, curving edge 123a, section piece 132, downwardly sloping edge 132a and interception point 1321; serving to define the passageway through which an end of support rod 112 is threaded for conveyance of the X-ray plates from the developer bath to the first rinse water bath are matched precisely, design-and layout-wise, by curving edge 134a, section piece 136, downward sloping edge 136a, and interception point 136b. The latter guideposts serve to define the passageway for the support rod end through the bath-unit increment leading from the first rinse water bath to fix solution bath 79.

Upon completion of the last-indicated cycle of travel, the rack-load of X-ray plates is permitted to remain immersed in the fix solution bath for a programmed interval of time, and then the elevator automaticaly repeats its ritual of up-and-down travel, at the same time conveying the rack through another bath-unit increment to deposit the same in the fourth and final bath, this being the second rinse water bath, shown at 77 on the drawings. Here again, the passageway for routing the appropriately oriented end of support rod 112 from its low position in vertical channel 14ac to that in 14ad, which is directly over the second rinse water bath 77, is identical to each of the previously described passageways through the first two bath-unit increments of guideway network system 14a. This will be evident from an inspection of the mapped layout of that guideway network system in FIG- URE 2 or 3.

As in the case of the previous three immersions, the rack and its load of X-ray plates remains in the second rinse water bath for a prearranged period of time, after which the elevator drive system is again automaticaly activated, and the elevator once again ommences its upward journey. The forward progression of support rod 112 as it is being lifted by the elevator to its high point of travel is similar to that heretofore discussed in connection with the incremental conveyance of the rack of X-ray plates from each bath in the developing system to the next, and the passageway followed by the end of the support rod captive in the 14a guideway network system is similar to its counterpart in the previously mentioned bath-unit increments thereof to its high point of curvature shown on curving edge 138a, which corresponds to previously mentioned curving edges 128a and 134a. Beyond that point, the passageway is different from those previously described because of the substitution of a differently shaped piece of plexiglass 140 for the familiar pentagonally-shaped section exemplified by section pieces 132 and 136 heretofore appearing at this juncture.

While section piece 140 has upper bounding edges somewhat similar to those of section pieces 13?. and 136, including a sloping edge 1400 similar to each counterpart edges 132a and 136a on the aforesaid section pieces, respectively, it, additionally, has an upstanding leg 14012 rising from a point of interception of its inner edge with sloping edge 140a and terminating at the top on a level even with the top of sidewall 6 (as, incidentally, do those plexiglass sections Within group 14 which form the top row of the group). As FIGURES 2 and 3 clearly show, where the inner edge of leg 1443b of plexiglass section 140 intercepts downwardly sloping edge 1401: a pocketlike notch, shown at 1400, and hereinafter designated as notch 1400, is formed.

As the moving end of support rod 112 starts to descend with the elevator after its upward progression to the far end of curving edge 138a, it drops down to eventual contact with sloping edge 140a and then follows that down to its point of interception with leg 14012 at notch 140e, whereat it is caught and held. The elevator continues to descend, leaving the support rod suspended at the level of notch 140c which is, as the drawings show, high above the liquid baths and closest to, but to the right of, the second water rinse bath. The movement of support rod 112 to its notch 1400 position of entrapment brings rack into pressing contact with lever 73 of the previously mentioned drying switch, which is so sized and positioned within housing 2 as to make such contact possible. Drying switch lever 73 is urged to the right, as viewed in the drawings, by the weight of rack 85, and this causes the switch itself, shown at 142 in screw-fastened position on the floor of housing 2, to energize a hot air blower 144 and thereby create a stream of warm air to dry the X-ray plates as they hang suspended in rack 85. The hot air blower is fixedly secured, by suitable means, to the inner surface of front end wall 10 of housing 2, at such elevation and wall position as to best serve its purpose. A preferred blower arrangement is shown in the drawings, which depict blower 144 so sized, positioned and ducted as to bath rack 85 in a stream of warm air flowing downwardly at the right angle to carry moisture from the rack and X-ray plates toward the second rinse water bath zone.

After a predetermined drying period, the X-ray plates are ready to be removed from the apparatus. A warning signal light, which is automatically controlled to go on at the beginning, and off at the end of the drying period, forms a part of the automatic control circuit of the developer. The circuit particulars of the blower and signal light units of the developer will be postponed pending later discussion of its automatic control circuit in detail.

Before leaving the subject of rack movement within the automatic developer, it is pointed out that access can be had to any of the bath zones in the illustrated embodiment thereof through entranceways into 'guideway networks 14a and 16a for the ends of support rod 112.. Two of these entranceways 14ae and 16ae, have already been discussed. Exemplary of the others are entranceways 14a Mag and Mali, which admit one end of support rod 112 to permit lowering of rack 85 into the first rinse water, fix solution, and second rinse water bath zones, respectively. There are various reasons why it is sometimes desirable to gain access to one or more of the bath zones in this fashion, none of which need be discussed here. My automatic developer is not limited to use with four liquid baths as shown in the drawings, and can be employed with fewer or more baths for X-ray developing purposes, or other dipping procedures to which the apparatus lends itself after relatively minor modifications, well within the ordinary oapabilities of those skilled in the art, of the equipment, procedures, or both, taught herein.

Turning now to the third major subject matter area of my invention, as it is outlined above, namely,the automatic control system for the pictured developer apparatus, attention is first directed to the FIGURE 10 circuit diagram of that system, which shows all of its e1eotricalc0mponents and the manner in which they are wired together to accomplish their cooperative purpose. All of the components of the circuit diagram, except the manual override switch, are illustrated elsewhere in the drawings, the latter being omitted because it is an optional feature *andrelay switch 15% with its actuating not necessary to proper functioning of the control system, and also since the choice of manner and place of installation of the override switch in the control circuit is well within the ordinary capabilities of one skilled n the art, particularly in view of the FIGURE teaching of an operative location for such a switch in the circuit there depicted. While, :as indicated, all components of the FIG- URE 1O circuit except the manual override switch are variously illustrated throughout the drawings, no attempt has been made to show the connective wiring of the components anywhere except in the FIGURE 10 circuit diagram. The chief reasons for omitting the wiring from the drawings (other than FIGURE 10) are the extreme difficulty of attempting to pictorially show the spaghetti-like mass of wires interconnecting the various components of the electrical circuit; the confusion which would result from inclusion of all these wires in the drawings; the teaching of the wiring arrangement for the circuit in FIGURE 10; and the fact that no one skilled in the art would have serious difiiculty in constructing the FIGURE 10 circuit mm the totality of teachings herein.

Electric power for the openation of the illustrated embodiment of my automatic developer is obtained from a 1i5-volt A.C. current source, by means of a standard plug connector, not specifically illustrated, but symbolized at 146 in FIGURE 10 by the pair of wire terminals there indicated. The current is fed into the control circuit through a panel switch 143, which is maintained in the off, or open circuit, position during non-use of the automatic developer, and flipped on to put the unit in operation. As the wiring diagram shows, a cam switch is connected in series inthe circuit with panel switch 148. Cam switch 150 comprises a rotatable cam disc 150a and a relay switch 15% with a spring lever actuating member 150M, these parts being anchored, within a walled enclosure 156, to the floor, and near the front end, of housing 2, as shown in FIGURE 4. Cam switch 156 is oriented with its cam discparallel with front wall It) of housing 2, member 15mm angling upwardly and contacting the rim of the cam disc under a slight tension.

Cam switch 159 operates off of a timer motor 158 to which it is connected by drive means. The timer motor causes cam disc 150a to slowly rotate in such direction that its outer rim continuously moves out from under the end of spring lever actuating member 15tiba of relay switch 15011. The purpose of cam switch 150, as will later appear, is to shut off the whole unit after a certain predetermined period of time. To effectuate this purpose, the peripheral edge of cam disc 150a is so positionally notched, relative to the shaft speed of the timer motor 158, as to bring the resulting notch into alignment with the outer end of spring lever actuating member 1505a, after lapse of the aforesaid predetermined time period. Cam switch 150 remains closed so long as the outer end of spring lever actuating member IStlba rides on the uninterrupted edge of its cam disc. However, when the movement of the cam disc brings the notch in its rim into coincidence with the outer end of lever member 15tlba, the tension on the member forces its end into the notch. When this occurs, the inner end of the member is displaced sufliciently to cause the opening of relay switch 15%, thus interrupting the flow of current in the circuit. How this fits into the operation of the control circuit will be better understood as the description of the circuit proceeds.

When panel switch 148 is flipped to its on (closed circuit) position to place the automatic developer in operation, switch 150 is in its closed circuit position and its notched disc is so positionally calibrated as to bring the de-activating notch on its peripheral rim into switch-opening alignment with spring lever actuating member 1501M at the precise moment when the time required for the developing and drying of the X-ray plates in the apparatus in accordance with the teachings herein has expired.

Consequently, after the processing of X-ray plates has run its full course in the developer, cam switch automatically opens the control circuit, thus shutting down the whole system. The only purpose of cam switch 150 is to effectuate this final de-activation of the control circuit, hence it remains closed during the entire cycle of operation of my automatic developer. Since the time requirement for full-cycle operation of the developer will vary, depending, among other things, upon solution ternperatures, which have an effect on X-ray plate immersion times, it is desirable to have some means of adjusting the initial peripheral distance on cam disc 156a between the point of contact of spring lever actuating member 1591M thereon and the switch-opening notch of above reference, to thereby regulate the total operation time of the apparatus. This is accomplished by means of a pointer 160, rigidly secured to the end of a shaft 162 in perpendicular relationship thereto. Shaft 162 is sulficiently long to extend from a point in front of housing 2 through its front end wall and to coactive and coaxial connection with cam disc 159a, whereby turning of the pointer, and hence shaft 162, turns the cam disc through the same angular displacement. To reach cam disc 150a, pointer shaft 162 extends through, in addition to front wall 10 of housing 2 already mentioned, the front Wall of enclosure 156, which, as previously indicated, encloses cam disc 159a, and another cam disc 166a disposed parallel to, and in coaxial alignment with, cam disc 150a. The shaft is hearingly supported in appropriately aligned openings in front wall ll) of housing 2 and the front wall of enclosure 156, and is connected to cam disc 166a in the same coactive and coaxial relationship that it bears to cam disc 150a. This shaft penetration of the intervening barriers between pointer and cam disc 150a, as well as its connective relationship with cam disc 166a, is shown in the drawings. The drawings also show various hardware items which are employed in the assembly, but these need not be presently discussed because the nature, manner of use, and function of each will be readily understandable to those skilled in the art from the drawings alone. Cam disc 166a, and its complementary parts and function, will hereinafter be described in detail.

As FIGURES 1 and 4 show particularly well, the length of shaft 16a is such as to position pointer 160, which is affixed to its outer end, as earlier noted, in close adjacency to the outer surface, or panel, of front wall 10 of housing 2, but with sufiicient clearance between the pointer and the wall to permit non-binding rotation of the former around the axis of the shaft. A panel dial 170 is fastened flush against the outer surface of front wall 19 of the developer housing, the dial being positioned within the sweep range of pointer 160 and offering a selection of time readings, the exact nature of which will be subsequently discussed. Suffice it now to say that the pointer and dial provide a means of regulating the operating condition-s within the developer through adjustment of the time schedule to be followed by its internal working parts. The actual timing of the various steps involved in my automatic developing process, which, as will be apparent from the above, forms a part of my invention, is accomplished through calibration of cam disc 166a, further discussion of which will be postponed until later. The timing of a complete cycle of operation of the developer is regulated by cam disc 150a, which is adjusted to a preselected time setting by means of pointer 160 and interconnecting shaft 162.

The dial on the front panel of housing 2 has time readings for pointer selection and concurrent adjustment of the position of cam disc 166a for performance consistent therewith. Cam disc 166a, as indicated above, controls the timing of the various procedural phases of my automatic X-ray developing process and, hence, dial 170 has time readings directly tied in with this function, typical of which are developer solution immersion times. While dial 170 typically reads in such a way as to focus attention

Claims (1)

1. 9. AN AUTOMATIC DENTAL X-RAY PLATE DEVELOPING APPARATUS COMPRISING, IN COMBINATION: (A) CONTAINING MEANS FOR A PLURALITY OF X-RAY DEVELOPING SOLUTION BATHS; (B) SUPPORT MEANS FOR SAID CONTAINING MEANS FOR SAID BATHS; (C) ELEVATOR MEANS ADAPTED TO MOVE UP AND DOWN THROUGH A FIXED PATH OF TRAVEL, AND SUPPORT AND MOVEMENT GUIDANCE MEANS THEREFOR; (D) ELEVATOR DRIVE MEANS, INCLUDING PRIME MOVER MEANS AND MOTIVE POWER TRANSMITTING MEANS INTERCONNECTING IT WITH SAID ELEVATOR MEANS SO CHARACTERIZED AS TO INDUCE THE LATTER TO MOVE THROUGH ITS FIXED PATH OF TRAVEL UPON ACTUATION OF SAID PRIME MOVER MEANS; (E) HOLDING MEANS FOR DENTAL X-RAY PLATES SO SHAPED, SIZED AND POSITIONED AS TO HOLD THE PLATES IN ANY SPACE WITHIN SAID CONTAINING MEANS FOR SAID BATHS ADAPTED TO CONTAIN A BODY OF BATH SOLUTION, AND SO CHARACTERIZED AS TO PERMIT CONTACT OF BATH LIQUID SOLUTION THEREIN WITH SAID X-RAY PLATES DURING OPERATION OF SAID DEVELOPING APPARATUS; (F) SUPPORT AND CARRYING MEANS FOR SAID HOLDING MEANS ADAPTED TO REST ON SAID ELEVATOR MEANS AND RIDE IT, IN HORIZONTALLY SLIDING RELATIONSHIP, AS IT TRAVELS UP AND DOWN THROUGH ITS FIXED PATH OF TRAVEL, SAID SUPPORT AND CARRYING MEANS HAVING OUTWARDLY EXTENDING PROJECTIONS; (G) GUIDE MEANS ADAPTED TO ENGAGE SAID OUTWARDLY EXTENDING PROJECTIONS AND INDUCE THEM TO TRAVEL FORWARDLY A PREDETERMINED DISTANCE DURING EACH UP AND DOWN TRIP OF SAID ELEVATOR MEANS, THEREBY CAUSING FORWARD PROGRESSION OF THE ASSEMBLY COMPRISING THE SUPPORT AND CARRYING MEANS FOR SAID HOLDING MEANS. THE HOLDING MEANS PROPER AND ANY DENTAL X-RAY PLATES HELD THEREBY SAID PREDETERMINED DISTANCE WITH EACH UP AND DOWN TRIP OF SAID ELEVATOR MEANS DURING OPERATION OF THE DEVELOPING APPARATUS, COMPRISING: (1) A PAIR OF WALL-LIKE MEMBERS DISPOSED EITHER SIDE OF SAID SUPPORT AND CARRYING MEANS IN GENERALLY PARALLEL RELATIONSHIP, THE FACING SURFACES OF SAID WALL-LIKE MEMBERS BEING DISTINGUISHED BY THE PRESENCE OF GUIDE-WAY CHANNELS FOR SAID OUTWARDLY EXTENDING PROJECTIONS, THE CONSEQUENT CHANNEL PATTERNS ON THE TWO WALL-LIKE MEMBERS

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