US2818043A

US2818043A - Photoengraver's powdering cabinet

Info

Publication number: US2818043A
Application number: US417090A
Authority: US
Inventors: Smith Otto Telfair; Jr George A Butter
Original assignee: Konica Minolta Graphic Imaging USA Inc
Current assignee: Konica Minolta Graphic Imaging USA Inc
Priority date: 1954-03-18
Filing date: 1954-03-18
Publication date: 1957-12-31
Anticipated expiration: 1974-12-31

Description

Dec. 31, 1957 o. T; SMITH ET AL 2,- 8 'l8,( )43 -PHOTOENGRAVERS POWDERING CABINET Filed March 18,. I954 3 Sheets-Sheet l? INVENTORS OTTO TELFA/R SMITH BY GORGE A. BUTTER, JR- Wa ATTORNEYS- Dgc. 31,1957

o. T. SMITH ET AL 'PHOTOENGRAVERS POWDERING CABINET 3 Sheets-Sheet 5 Filed March 18, 195

R H wn 5 8 5 WM N e N r R mew w Nm T I 0 MA @WA W W TM 0 H Y M United States Patent 'PHOTOENGRAVERS POWDERING CABINET @tto Telfair Smith, Muttontown, and George A. Butter, Jr., Levittown, N. Y., assignors to Powers Chemco, Inc, Glen Cove, N. Y., a corporation of New York Application March 18, 1954, Serial No. 417,090

9 Claims. (Cl. 118-11) The present invention relates to powdering cabinets used by photoengravers in powdering partially etched plates before further etching and has specific reference to such a cabinet having means to prevent powder escaping from the cabinet to atmosphere during the powdering operation.

Objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practice with the invention, the same being realized andattained by means of the instrumentalities and combinations pointed out in the appended claims.

The invention consists in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate one embodiment of the invention, and together with the description, serve to explain the principles of the invention.

In the drawings:

Figure 1 is a perspective view of the powder cabinet embodying the present invention and being partially broken away to show the mechanism within the interior of the cabinet;

Figure 2 is a vertical sectional view of the cabinet takengenerally along line 22 of Figure 3;

33 of Figure 2; and

Figure 4 is a diagrammatic view of the electrical circuit which forms as part of the present invention.

In preparing partially etched plates for further etching a dark red resin, known as dragons blood, is dusted onto the plates. In dusting the plate, a flat brush charged with the powder is swept across the plate in four different directions varying approximately 90 with the plate being heated after it has been dusted in each direction, this heating melting the powder so it becomes fused and forms an acid resistcnt coating. By dusting in this manner, the powder is effectively appliedto the partially etched image so that when the plate is treated with acid for further etching the relief will be increased without undercutting or losing the detail.

During the dusting or powdering operation the fine powder is agitated so that particles of the powder rise into the air in the fashion of dust. For the safety of personnel as well as other reasons it is essential that this powder does not escape and become lost to the atmosphere. It is for this reason that the powdering operation is conducted in specially designed cabinets.

The present invention has for its objects the provision of an improved cabinet for use in powdering partially etched plates and wherein the powder that rises from the plate during the powdering operation is recovered by means of a downdraft air flow system without disturbing the quiescent atmosphere in the vicinity of the plate or in any way interfering with the powdering of the plate. Another object is an improved powder cabinet having a recovery system for the powder rising from the plate In accordance with the illustrative and preferred embodiment of the invention the powder cabinet comprises a base on the upper end of which is a box-like hood provided with spaced vertical side walls interconnected by spaced vertical front and rear walls. The top of the hood is entirely open and the front wall is considerably lower than the rear wall with the upper edges of the side walls preferably sloping gradually downward from the Posi-.

top of the rear wall to the top of the front wall. tioned within the hood is a powder tray of generally the same configuration as the hood but smaller in all respects so that it is contained entirely within the hood with the upper edges of the walls of the tray being below the corresponding edges of the hood and with the walls and bottom of the tray being spaced from the walls and bottom of the hood thereby providing a narrow passage for air flow all the way around the tray. The interior of the hood and the interior of the base are separated by a plate which forms the bottom of the hood and which is provided with a pair of openings each of which has an upright fabric filter bag positioned therewithin and depending into the base of the cabinet. Within the base is a fan driven by an electric motor and adapted to apply asuction. to the interior of the base causing aflow of air downward through the passage surrounding the powder tray, into the open upper end of the filter bag, and through the wall of the bag into the interior of the base from which it is exhausted by the fan to atmosphere. I

In flowing through the wall of the filter bag the powder, that is entrained in the air is removed and remains in the interior of the bag. Attached to these filter bags is an electric vibrator operative when energized to shake the bags to remove the powder that clings to the inner wall of the bags, this powder falling into the bottom of the bag leaving the walls relatively clean for eflicient filtering operation. and the vibrator is controlled through suitable electric circuits which include a switch means operable when in one position to energize the motor and de-energize the vibrator and when in another position to tie-energize the motor and energize the vibrator. In the circuit associated with the vibrator is a switch automatically operative to de-energize the vibrator a predetermined time after it has been energized.

Referring now to the drawings, wherein like reference characters are used throughout to designate like elements, the illustrative and preferred embodiment of the powder cabinet of the present invention shown therein comprises base It) provided with side walls 14, rear wall 16 and bottom member 18. The inner portion of the front 20 of this base is recessed as shown and provided at its upper end with a receptacle for drawer 21 beneath which is access opening 22 normally closed in a fluid tight manner by removable plate 24. The front wall 20 and side walls 14 of base 10 extend below bottom member 18 and provide a footing for the base in engagement with the floor upon which the cabinet is placed with passage 23 being formed between the bottom member and the floor and leading out the back of the cabinet.

Upon the upper end of base It) is formed the hood portion of the cabinet, this hood portion being generally designated 12 and including bottom plate 25 preferably positioned on top of base 10 and forming what may be termed the roof of the base with the front end of the plate being bent upwardly to form the front wall 26 of I the hood. The side and rear walls of the hood are Energization of the electric motor formed byupward extensions of side walls 14 and rear wall 16- of base 10 with the rear wall 16 ofthe hood being substantially higher than front wall 26 as shown and with the upper edges of side walls 14 sloping gs 'adually downward from thetop of the rear wall to. the topofi the-front wall thereby giving the operator a maxi.- mum of working freedom whiclrp romotes-both production and quality. 7

Mounted within hood 12 is; powder tray 27 havingside walls 28, rear and

front walls

30 and 32, respectively, and bottom 34. The tray is pivotally mounted about rod 36 which extends through a suitable bead formed atthe'upperedge of rearwall30. and has its opposite; ends secured to-side-wallsfl of the-hood"; When the powdertray is i'n-its normal or operative position, shown in ,full lines i'rrFi'gure 1 and'dottcd lines in Figure 2; the head or loop provided on the upper edgeoffrontwall; 32 is in engagemeutwith stop member 38 secured to side wall 14 of the hood and bottom 34 is inparallel; relation with but spaced from bottomplate 25 of the hood forming passage 4-0 tlierebetween. The side walls 28' and front and rear walls 32' and 30 of thetray' are respectively spaced' from sidewalls 14 and front: and

rear walls

26 and 16 oh the hood thereby formingannular passage 42- about" tha tray and communicating: at itslower end withpas sage: 40:;

For the purpose of' somewhat guiding tray 27 inits pivotal movement about rod 36 and for-retainingthe tray in: its extreme upwardly tilted position bracket; 44 has one-end pivotally mounted to-the bottom ofthe-tray with its other end pivoted to member 46 whichis in' turn. slidably mounted on track 48; As tray27 is'tilted upwardfrmemben 46 slid'es along tracle48 until bracket 44 is substantially vertical whereupouthe-bracket will hold the tray in this; position. the; powder in the tray collects. at-the back of thetray makingt'it relatively easy: to remove the powder with this removal being facilitated by plate 50 which extends acrossthe; lower: rear edge -of the tray.

Rivotally mounted on the upper edge'ofi-f'rontwall 26 of the hood is shelf 60 which is movable between its full line position in Figure. 2' where it permits pivotal movement' of tray 27' and its fulllineposition in Figure 1 where it extends over and is spacedfrom the upperedge of the front-wall of the tray andprevents foreign matter falling in; the: spacevbetween the front wallsof} the'tray and the hood.

Inlbottom plate 24' is: a pairof openings 52 within-each of; which, is an upright close mesh fabric filter bag 54 preferably made of nylon andWhich extends downwardly intoithevinterior of base 10; The rimf'bag'54'is' formed" with, a rigid. annular member. 56. disposed therein with this; rim being slightly larger than opening 52 therebyforming a radial flange etfective=to support the bag. To prevent: the bagsefrom collapsing and becoming out of shapeseach oithern has-1mhoopfifi positioned in thebot-- tom.

During: the'powdcring of a.plate=.within tray 27, suchasaplatettil' heldby'hand or: placedeontshelf- 60; a continuous downdraft is created in. annular passage 42 by fan- 64 mounted within base 102 andrhaving its inlet communicating; with the interior of:the base: and its outletz communicating with passage 23. The base is sufii-- By: tilting the tray in this-manner By creating a downwdraft through annular passage 42 the entire tray is surrounded by a current of air moving toward the passage 42 with the air over tray 27 moving generally outwardly from the center toward each of the walls whereby no rush of air above or across the tray from one end to the other is created as has been the case heretofore and whereby. the quiescent atmosphere necessary for quality work is undisturbed while dust collection efficiency is greatly improved.

In: order, to maintain the. ethciencyof filter bags 54: at their maximum a shaker-is provided to periodically shake the bags to'removetthe powderthat clings to-the interior wall ofther bags with this powder falling to-and collecting in the bottom of the bag. The bags are ofsufiicient size so that under normal operation they need emptying only about twice a year with the emptying operation being accomplished by tilting tray 27 to its uppermost position and then removing the bags upwardly out of the openings 52.

As illustratively disclosed the means for shaking bags 54 comprises electromagnet 66 having its armature 67 normally biased to a nonvenergized position by spring 68 and connected with the bags by cross bracket 70 pinned to the radially extending ears 72 which form part ofannulan frame 74' secured to each of the bags. EX- tending laterally from armature 67 is bracket 76 which has a pair of fingers 78' between which is positioned switch 80'forminga' part of the circuit of electromagnet 66 and'arranged to open and break the circuitvwhen armature 67 is moved to its extreme position within the coil of the electromagnet in responsehto .energization of the electromagnet and to close when' armature 67is moved to its other extreme position by spring 68 with the limit of thesetwo extreme'positionsbeing determined by stops 82 which engage bracket 76'. Thus when the circuit of el'ectromagnet 66- is energized armature 67 will rapidly move back and forth'between these' extreme positions because of the opening and closing of switch 80 thereby resulting in shaking filter bags 54;

The operation of' fan 64- and electromagnet 66 is controlled by an electriccircuitdiagrammaticallyillustrated in Figure 4 and arranged so that when the-motor-84 of the fan is energized electromagnet 66"will not be energized and can only be energized after motor 84 has first been energized'and then de-energized. Electromagnet 66 will be energized only for a predetermined time after which it will automatically bede energized. This circuit comprises a pair ofl'eads86and 88 connected with a suitable source of" potential and across whichare connected motor 84'and-coil of relay 90inparallel relation with; each other with the circuitof-motor 84 including conductors'92 and 94 andthe circuit of relay 9fl=including conductors 96' and 98 Forminga portion of the conductors 92 and 96i's switch 100=whichis preferably a double pole, double throwswitch of' the toggle type without an ofiposition. When switch: 100* is moved' to the right, as viewed in Figure 4, into engagement with-

com tacts

102 and 104, conductors 92'and 96; respectively, are completed while when it-' is moved to-its left in engagement with contact 106 both of these conductorsare broken andtcontact 106 is connectedto relay-90 through a portion of conductor 96.

Thus when switch 100 is moved 'to its right position motor 84 and relay 90 arelenergized. Energization of relay 90 causes normally open'contacts 108 and=110 of the relay to close and establishes through conductor 112 a holding circuit for the relay in parallel with-switch 100 so that when the switch is'moved to its left position relay 90 will remain energized-:wliilemotor will become de-energized.

The circuit for electromagnet 6'6' includescontact'106; conductor 114; a series connected switch 80* and conductor 116 which is connected to lead-88. Whemswiteh 100 is'moved fromits right to its left-positioninengagement with contact 106' this circuit' of) electromagnet 66' asiaoas is completed across leads 86 and 88 since contact 106 is then connected with lead 86 through

conductors

96 and 112 and contacts 108 and 110. However, should relay 90 become de-energized causing contacts 108 and 110 to open the circuit of electromagnet 66 would of course become de-energized.

In series with coil of relay 90'and forming a part of conductor 98 is thermal switch 118 which comprises bimetal element 120 in engagement with contact 122 at normal temperature and movable out of engagement with the contact when its temperature is raised to a predetermined value. Immediately adjacent to bimetal element 120 is resistance heater 124 connected across

conductors

114 and 98. No current can flow in resistance 124 until contacts 108 and 110 of self-locking relay 90 are closed which is accomplished by throwing the switch 100 to the right. Resistance 124 then is in a position to receive current when switch 100 is thrown to the left hand position making contact 106 which completes the path to resistance 124 namely conductor 88, thermal switch arm 120, contact 122, conductor 98 to heater,

conductor 114, contact 106, switch 100, conductor 96,

conductor 112 and contacts 108 and 110 to conductor 86. When switch 100 is thrown left connecting to contact 106 the circuit of electromagnet 66 is energized, current will flow from conductor 114 through the resistance heater to conductor 98 causing the resistance heater to become hot and thereby heat bimetal element 120 resulting in switch 118 being opened which will in turn de-energize electromagnet 90, opening contacts 108 and 110, with resulting de-energization of the circuit of electromagnet 66.

Since switch 100 is preferably of the toggle type it will at all times occupy either its right position in engagement with

contacts

102 and 104 or its left position in engagement with contact 106.

In operating the cabinet of this invention, when it is desired to powder a partially etched plate switch 100 is first moved to the right completing the circuit of motor 84 thereby causing fan 64 to draw air downward through passage 42 and also completing the circuit of relay 90. Energizing of relay 90 causes contacts 108 and 110 to close thereby completing the holding circuit of the relay which is in parallel with switch 100. After the powdering operation is completed and it is no longer necessary to run fan 64, switch 100 is moved to the left into engagement with contact 106. This movement of switch 100 de-energizes motor 84 but because of the holding circuit does not de-energize relay 90. Upon moving the switch into engagement with contact 106 the circuit of electromagnet 66 is completed resulting in shaking of the filter bags 54. Also incident to energization of the circuit of electro-magnet 66 resistance heater 124 begins to get hot and after a predetermined time, depending upon the resistance value of the heater, it will have heated bimetal element 120 sufiiciently to cause it to move away from contact 122 which will de-energize relay 90 and consequently cause de-energization of the circuit of electromagnet 66. Thus filter bags 54 will be shaken only for a short time sufiicient to remove the powder from the inner walls thereof after which the electric vibrator will be automatically de-energized.

The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What is claimed is:

l. A powder cabinet of the type described comprising a hood forming the upper portion, said hood having an open top and a front the major portion of which is open, a powder tray having side, rear and front walls and providing a normally horizontal working surface disposed within said hood, said tray being smaller than said hood 6' so that passages are formed between the side', rear and front walls of the tray and the hood and the tray is positioned entirely within the hood, means in the lower portion of said cabinet effective to draw air downwardly through said passages, and separator means through which said air is directed for separating foreign matter therefrom.

2. A powder cabinet for use in preparing plates for etching comprising a generally upright base, a hood mounted on said base and forming the upper portion of the cabinet, said hood being open on the top and having elements comprising a bottom and generally upright walls enclosing the front, rear and sides thereof with the front wall being substantially lower than the rear wall and with the edges of the side walls sloping from the rear wall downward to the front wall, a powder tray providing a normally horizontal working surface and being of generally the same configuration as said hood and disposed entirely within said hood, the bottom and walls of said tray being spaced from the corresponding elements of said hood thereby forming a narrow passage for airflow entirely surrounding said tray, said tray being pivotally mounted adjacent the rear wall of said hood about an axis extending along the upper edge of the rear wall of said tray the bottom of said hood having an opening therein, a fan disposed in the base of the cabinet and effective to apply a suction to said passage through said openingcausing a downward flow of air through said passage on all sides of the tray, and an upright close mesh fabric filter bag removably disposed within said opening for removing foreign matter from the air drawn through said opening.

3. A powder cabinet as defined in claim 2 including a shelf hingedly mounted on the upper edge of the front wall of the hood and positionable so as to extend toward the rear of said hood beyond and above the front wall of the powder tray.

4. A powder cabinet of the type described comprising a base, a hood positioned on the upper end of said base, said hood having a generally horizontal bottom member, a pair of spaced side walls extending upwardly from said bottom member, a front and a rear wall extending upwardly from said bottom member intermediate between and interconnecting said side walls, said front wall being substantially lower than said rear wall and the upper edges or" said side walls sloping gradually downward from the top of the rear wall to the top of the front wall, a powder tray having a bottom and side, rear and front walls disposed within said hood, the bottom of said tray providing a Working surface and being spaced above the bottom member of the hood and the walls of the tray being spaced from the walls of the hood thereby forming a narrow passage completely around said tray, the upper edges of the Walls of the tray being positioned below the corresponding edges of the walls of the hood, said tray being pivotally mounted with respect to the rear wall of said hood and about an axis at the upper edge of the rear wall of said tray the bottom member of the hood having an opening therein, an upright filter bag disposed Within said opening, substantially filling the same and depending into the base of the cabinet, and a fan in the base of said cabinet effective to draw air downwardly through the passage around said tray and into said bag and through the wall thereof.

5. A powder cabinet comprising an upright base, a hood having side, rear and front walls and mounted on said base and forming the upper portion of said cabinet, said hood being adapted to have a powder tray providing a working surface disposed therein with the peripheral extremities of said tray spaced from said hood walls to provide a passage for air flow surrounding said tray, a fan in the base of said cabinet effective to draw powder laden air throughv said hood into said base, an upright air "enters" the =-open upper end of the bag and passes throughthe-wall of the bag, an electricrnotor -connected to said fan, switch *rneahwmovablebetween a first and-asecondposition and being' eonstructed and arranged to occupy one of said positions at all times, said switch means having a pair of'contactv forming apart 'of the circuit of-said motr said contacts .being 'closed'whentlre switch means is-in one o'fisaid positions and =-openwhen in the =otherof said an -electric -vibrator "connected to said bag and tipentive'to'vibra tethe same when energized; said switch means having; again of contactsforminga part ofithecirctfitofisaid vibrator; thelast named contacts being closed when the-switch means is in i said otherposition-"and open when in said one position, and means operative a predetermined time'after energization of said vibrator to de-energize the same.

6. Apowdercabinct comprising-a base; 'ahood mounted on said base and--havingfront;rear and sidewalls, 'a powder tray providing a workin'g'surf'ac'e disposed within-said hood andwhaving its periphera'l extrernities-spaced from said' hood walls'to form --an*air 'flow passage'snrrounding said tray, an -upright fitter-bag in-saidcabinetpa fan operative to -draw powder *laden air through saidhood air flowpassageyinto the open-upper end -of the filter bag and through thewal-l some bagflmeans fondriiring said fan including -an-electric motordisposed i-n'an electric circuit adapted to beconnected'across-a potential; an electric switch means in said'circuit and movable between a first and a second position hocauseenergization and de-energization respectively of said circuit, said switch means being constructed and'arrangedtb-atall "times o'ccupy one of said positions-a second-icircuit inparallel with the first mentioned circuit andincluding an electric vibrator 'operatively-con'nected to said filter bag, said switch means including means efiective to makeand break said second-circuit whenasaid sw itch means occupies its second and first-positions respectively,additional means in saidsecond circuit effective to control energization thereof, said means being conditioned in response to said switch means occupyin'g' its-said first position to permit energization of saidsccond circuit, means operable to maintain said controhm'eans so conditionedpwh'en said switch 'means is moved from-its first to'its second position, and .means effectively responsive to'energ'ization of said second circuit and operableafter said second circuit has been energized for -a predeterrnineddime-to condition said control means it to prevent 'energization ofsaid second circuit.

7. Apowder cabinet comprising a base, a hood mounted on said base and having-front, rear 'andside walls, a powder tray providing a working surface disposed within said I hood and having its peripheral extremities spaced from said hood walls to form anairflow passage surrounding said;tray, a close mes'h'filter bag in said cabinet, a fan operative to draw powder laden air throughsaid passage, into the open end of thefilter b'agand through the wall of the bag, an electric circuit including-amotor'connected to drive said fan,switch-means having a pairof contacts in said circuit, 'said' switch means being movable between a'first and second position to respectively close and open saidcontacts, a second circuit in parallel with said motor and including a pair of contacts forming a part of said switch means, said 'contacts being in engagement when the switch :meansislin-saidfirst-position :andseparated when in said second position, a relay having its coil in series with, said second icircuit, the contacts of said relay being normallyiopen and 'being connected to form a holding :Icircuit :for ithe'zrel'aytin iparalle'l with "said contacts :in ;said tsecond' circnit, a :normally closed therrnal switch .iniseries iwith,=said-:second circuit and said holding circuit, said swi ch: tmoying ito tan openiposition upon reaching a predetermined high temperature, a mag netic vibratoroperatively connected to saidfilter bag, said vib rator'being in-series with said holding circuit and parallel with said relay coil andsaid thermal switch, said switchmeansincludihgmeans'operative toopcn the vibrator circuit when said switch means is in said 'firstposition' and-: completesaid vibrator circuit-when said switch means-is'insaid second position, an electric resistance heaterjuxtaposed to' said thermal switch and connected in series'withthe last mentioned means and said thermal switch.

8. A powder cabinet 'used in preparing plates for etching "comprising a base, a hood'disposed .on the upper end ofjsaid base, said hood havingan open top, and generally vertical 'walls'with the front wall being substantially lower than the rear wall, the interior of said hood'being ,separatedffrom the interior of said base by a plate member having an opening jt'herethrough, a powder tray providing.

a working surface disposed within said .ho0d,-.said,'.tray

having a bottom and generally vertical walls spaced, from,

and dependingjnto .said, base, .an electric circuitinclud ing a motortfordriving said 'tfan, antelectric .circuitincluding a vibratortconnectedsto. said :bag, and effective to vibrate the samewvhen energized-switch tmeans tdisposcd in.thetcircnit. -.ofiisaid motor andythe circuit of said vibrator and movable between a first andza second position,

whereinwit is effective to respectively, makeand break the circuit-of thesmotortand break: and make the circuit oftthe vibrator, and .means responsive tto energization of,

said vibrator .cincuit'c-and operable to breaktsaid vibrator circuittafter energization1ofthe-same-for.a predetermined,

time.

9. .A powder-cabinet thaving a hood formingrthe "upper portion thereof, said hood'ha-ving sideand rear walls, ,an open topand altront ,the majorportionaof which;is open,

a powdcntray havingside, =rear and rfront wallsiand substantially centrally disposed within said .hood, :said 'tray providingazworking surface :andbeing generally iOf the same configuration !as said hood but smallertin allrespects so as totorm an annular passage about saidtrayvbetween,

the walls oftthetray; and ithe hoodtand so the:tray is positioned:entirelyrwithin -thethooi-a -fan in ,the lower position of the .cabinetoperativeato ,applya suction to :the lower end of,,said -.passa ge zandtdrawipowder laden air downwardly theret'hrongh, ,an upright fabricfilter bag disposed in .the path of 1 said powder laden i-air; means ,for driving said fan including;antelectrictcircuit iadapted to be iconnectedacross apotential, an: electric; switch :means in said circuitwandmovable. between a :first :and, a second position tozcauseenergization and-de-energizationrespectively of said. circuit,said.-switch means being constructed and arranged to at all times occupy one,of;said positions, a second tcircuitdn parallelwith tthe :first mentioned tcircuit and including zan'zelectric -vibrator, operatively connected to said filter bag,.said switch means including means-effectiveto (make andibreakssaid second circuit when said switch means :occupies iits second and first positions 'respectively, additional means in said second circuit effective to control energization thereof, said means being 'conditionediin-iresponse' to said switch means occupying its saidzfirst position to permit energization 'of -said second circuit, ,rneans operalile to maintain'saidcontrol means so energization 'ortsaia second circuit and operable after tion of said second circuit.

References Cited in the file of this patent UNITED STATES PATENTS Dobinson Dec. 31, 1929 10 Merrell et a1 May 27, 1930 Guenst Sept. 12, 1933 Black May 30, 1944 Smith June 19, 1951 Medcalf July 8, 1952 Bruckner Mar. 31, 1953