US2389319A - Dipping machine - Google Patents

Description

Ng'v; 2o, 1945'.

s'. McMoRDlE ETAL DIPPING MACHINE Filed Nov.` 10, 1941 12 SheelZS--Sheec` l v Nov. 20, 1945. s. McMoRDlE E'rAL n 2,389,319'

DIPPING MACHINE Filed Nov. 10, 1941 12 Sheets-fSheet-Z w w/ In kn. n 6.0 r f can ,We

S. MCMORDIE ETAL DIPPING IIACHINE Filed Nov. 10, 1941 12 Sheets-Sheet 3 fig-MT,

- Deu/gy J4. .fetersoru Nov.v20, 1945. s. McMoRDlE Erm. 2,339,319

bIPPING MACHINE Filed Nov. 1o, 1941 y 12 sheetssheet 4 s', McMoRDlE ET AL Nov. 2o, 1945.

DIPPING MACHINE Filed NQv. 1o, 1941 12 sheets-sheet 5 www.

Nov. 2o, 1.945. n s. MCMORDIE HAL. 2,389,319

DIPPING MACHINE Filed Nov. 10, 1941l 12 Sheets-Sheet 6 .linzen 5011521.

Nov. zo, 194s'. s, MCMGRDIE mL 2,389,319

DIPPING MACHINE Filed Nov. 10, 1941 12 Sheets-Sheet 7 Nov. 20, 1945. s, McMoRnlE E-rAL 2,389,319

DIPPING HAQHINE Filed Nov. 1o, 1941 12 sheets-sheet 8 Nov. 20, 1945. s. McMoRDlE ETAL DIPPING MACHINE Filed Nov.- l0, 1941 l2 Sheets-Sheet 9 Nov. 20, 1945.y

s. McMoRDlE ETAL 2,389,319

DIPPING MACHINE Filed Nov. 10, 1941 12 Sheets-Sheet 10 Patented Nov. 20, 1945 DIPPING MACHINE Stanley McMordie, Arlington,

and Dewey A.

Peterson, Chelsea, Mass., assignors to Dewey and Almy Chemical Company, North Cambridge, Mass., a corporation of Massachusetts Application November 10, 1941, Serial No. 418,598

' (Cl. lil-24) Z2 Claims.

The present invention relates to processes for forming articles by dipping and to apparatus for carrying out the processes.

The invention has particular application to the forming of rubber articles by dipping processes in which forms or molds are dipped into a liquid to form a\coating thereon which is subsequently stripped from the mold. It is to be understood, however, that the apparatus is useful generally wherever a dipping operation is required. K The specific apparatus illustrated and described herein is used to form rubber bags or balloons by a dipping process in which the mold is successively dipped into two diierent baths, one of which is a liquid latex compound and the other a coagulant for the latex, or an exhauster for overcoming the eiect of a stabilizing agent in the latex compound, to form on the mold a layer of rubber of the thickness desired. For a disclosure of the process of the latter type see application of Neileyand Habib, Serial No. 290,252, filed August 15, l939. As used hereinafter the term coagulant includes exhausters as defined in said application.

An object oi the invention is to provide dipping apparatus which will secure a uniform deposit' on molds of various shapes. 1n particular, one object of the invention is to provide a control system for varying the speed of.' dipping of the mold in accordance with the shape ofthe mold whereby the line oi' contact between the'surface of the dipping liquid and the mold moves along the surface of the mold at a substantially uniform rate.

A further object of the invention is to provide safety devices to prevent operation ci the dipping apparatus except when the mold carriage is in proper position in the apparatus.

A further object is to provide dipping apparatus driven by an electric motor, and to provide control means for stopping theoperation oi the 'motor for a predetermined dwell period when the dipping forms are completely immersed, and for automatically restarting the motor at the end of the dwell period.

Still another object is to provide control means for preventing coasting of the dipping apparatus at the beginning of the dwell period.

Another ob'ect is to devise apparatus to facilitate the stripping of the molded articles from the molds.

Still another object is to devise a conveyor system to facilitate movement of the mold carrages from one station to another.

Apparatus embodying the present invention'is embodiment of our dipping machine employing one vertically movable frame and one driving motor for dipping the molds into any one of a plurality of tanks;

Figure 2 is a front elevational view of the ap paratus shown in Figure 1;

Figure 3 is a fragmentary, vertical, sectional view, to an enlarged scale, taken through the center of the rotary mold frame;

Figure 4 is a side elevation of the mold bar for supporting the molds;

Figure 5 is a sectional View taken along line 5-5 oi' Figure 3;

Figure 6 is a fragmentary view showing the manner of mounting the mold bar in the rotary mold frame;

Figure 'I is an end view of the mold carriage taken in the direction of the arrows I-- in Figure 2;

Figure 8 is a sectional view oi one o! the control panels and the control switches associated therewith taken along the line 8-8 of Figure 1;

Figure 9 is a sectional view taken along line 9-9 of Figure 8;

Figure 10 is a front elevational View of one of the control panels;

Figure i1 is an elevational view of one of the molds with appropriate markings for indicatingv the points of change in dipping speed;

Figure 12 is .a circuit diagram showing the power circuit and the control circuits ior operating the machine illustrated in Figures 1 to 10 inelusive;

Figure 13 is a side elevational view showing a modified arrangement o! our dipping machine wherein each dipping tafels, provided with a separate, vertically movable frame and driving motor for raising and lowering the mold carriage, and wherein the mold carriages are moved from one tank to the other on a trolley system;

Figurev 14 is a side elevational 'View on an enlarged scale showing the details of construction of the arrangement associated with the tank;

Figure l5 is an end elevational view taken from the right-hand side of Figure 14, the iront end of the dipping tank being broken away;

Figure 16 is a side elevational view on an enlarged scale showing the details of construction of the mold carriage employed in Figures 13, 1i and'15;

Figure 17 is a fragmentary view on an enlarged Stale showing the details of a centering stop and on which it was formed.

the' clamp for clsmvlns the mold supporting frame to the mold carriage. Y.

Figure isisanendviewoithearrangement vshown in Figure 17; o

Figure 19 is a sectional view taken along line ll-It in Figure showing'a pian view of the controlA panel and the cooperating control switches; l Figure 20 is a diagram illustrating one mold shape for forming rubber-bags. appropriate markings being applied for indicating the points of change in dipping speed;

Figure 2l is a iront elevational view of a con- :trol panel suitable `for controlling the dipping of the mold shown in `Figure 20; l .Figure 22 is a plan view'showing the general arrangement ot the entire apparatus iorforming vulcanized rubber bags from latex and employing the apparatus illustrated in Figures 13 to 2l, 23,

' 24 and 25;

Figure 23 is a side elevational view showing a stripping mechanism for stripping rubber bags or other dipped articles from the molds;

Figure 24 is an 'end elevational view ot the stripper shown in' Figure 23;

Figure 25 isa fragmentary view similarl to slightly diiTerent position in its operation; v

Figure 26 is a side view of one of the mold forms showing a molded bag partly stripped from the mold; y

Figure 23, but showing the mold carriage in a l Figure 27 is a sectional view taken along lineY 21-21 of Figure 26, and

Figure 28 is a. iragmentaryvlew illustrating' stripped from the mold a molded bag' completely Referring rst to Figures 1 and 2. the main supporting frame I for the dipping mechanism is or may form vpart of the buildingstructure enclosing the machine. The main frame I is of rectangular construction and forms the support for a driving motor 2 mounted therein. Arranged 'immediately below the frame i is a substantially horizontal frame 3 supported at the lower ends oi.' four vertically'slidable guide rods 3a passing through suitable frame l. ends of guide rods 3a, and the crosshead Ibis supported upon a threadedlead-'screw 3c having threaded engagement with the crosshead. The lead-screw 3c is driven through suitable speedreducing gearing from motor 2 to raise and lower guide bearings ic formed in the supporting frame 3.,

Supported on opposite sides of vertically-movable Irame 3 are two horizontal vtrack elements or rails 3d and 3e which conveniently may be formed of two lengths of. I-beam. I

A horizontally movable mold carriage l conr sisting of a horizontal frame-like section and end frame sections 4a and 4b, is supported from rails 3d and 3e by suitable trolley wheels 4e arranged atthe four corners of the horizontal frame sec. tion la.

A number of dipping forms or molds 5 are suitably suspended from a mold bar or plate, generally indicated at-Sa in Figures 2 and 4. The mold plate is removably supported in a rotary mold frame which is mounted on a horizontal shaft 6 suitably .iQurnalled inbearings provided at the lower ends of frame portions 4a and '4b. The rotary mold frame is formed of end portions 6a and Bb secured to shaft 6 and extending 120th A crosshead 3b is secured to the upperf lmechanism' may be employed.

assa'sia above Theupperpartsoi endportionsloandtbareioinedbyasuitable 'barcwhichcarriesacounterwelshtldotsumcient weight to. make the entire rotary mold l trame," with the supported molds, top

, able spacer blocks Se' and if' secured tothe top tace ot shelves te and if, respectively. The mold v bars are clamped in position on shelves te andlf by identical clamp structures provided immediately above -each shelf, only one of which will be described. 'nie clamp constructionconsists of a clamping bar 1 arranged transversely of the mold bars and being guided for vertical movement by a pair ot pins 1a and 'Ib extending between spaced guide members carriedon each end of the clamping bar. the pins 1a and 1b being suitably supported in the web portion of the adjacent end-section of the rotary mold frame. Clamping bar 1 is moved vertically by a suitablev toggle connection to hand lever 1c the inner end oi' which isejournalled on shaft G.Y The toggles connection between the bar 'I and the lever 1c includes an arm 1d secured to the lever 1c andl rotating about the axis oi shaft 8, and an extensible link pivotally connected at one' en d to the ann 1d and at the otherend to the center of bar 1.

The extensible link comprises a sleeve 1e pivotally secured to the arm Id and a cooperating plunger 'If pivotally securedl to the center of the bar I with a compression spring 1g positioned in the sleeve le and acting against the end of plunger' 1f tending to i'orce the plunger out ofthe sleeve. When the hand lever 1c isin the position shown in dotted lines in Figure 5, the clamping bar 'l is in its raised position. When the lever is moved downwardly to the position shown in solid lines in Figure 5, the bar 1 is moved into contact with brackets ilu-5b and pressure is applied to the bar through the spring 1y. Upon further movement ofthe lever 1c downwardly, the arm 'Id passes beyond the dead center position of the toggle connection. An adjustable stop 'lh is provided to prevent further movement beyond the while we have `described a spense farm or clamping device, any other suitable clamping on each end ofthe shaft s is provided a crank arm 6g carrying a handle Ilufor manually rotatiing the rotary mold frame to any desired position. One of the crank arms 'ig is provided 'with a notch in the end thereof, as shown in Figure 7, for receiving a locking pin Si carriedin .the lower end'of a reciprocating locking bar ik supported in a suitable guide way on end-section 4c of the mold carriage. The locking bar 8k is normally biased to its lower, or locking position and is operated vertically to the unlocking position by means of a suitable electro magnet LM. A spring pressed plunger 6m is provided to move the arm 6g out of its dead center position when the locking' bar is position, and the rotary Xmold As shown in Figures 1 and.2, a pair oi.' elongated dipping tanks 8 and 9 are positioned below the vertically movable frame 3 and transversely of the rails 3d and 3e. The mold carriage ltrlli- 4c which is movably mounted upon the rails 3d and 3e may be moved into position over either tank, and suitable stop elements S8 and S8 are provided on one of the rails to stop the carriage in proper position over either tank. The mold carriage is moved from one position to another manually. x

Individual control devices are provided to control the dipping movement with respect to each of tanks 8 and 9. The control devices will be described for tank 8, and it will be understood that similar devices are provided for tank 9 and are identiiied in the drawings by reference numerals 9 having the same subscripts as the numeral 8. The control apparatus for tank 8 involves a vertical frame 8a mounted adjacent one end of the tank and preferably supported from one of the supporting beams la or Ib. The frame 8a is an open frame, and the vertical members of the frame are provided with vinwardly facing channels to receive a control panel 8b which may be vertically adjusted in the frame 8a by means of hand wheel 8c suitably journalled in a fixed support carried by the end of tank B and having threaded engagement with the lower end of the rod 8d which supports panel 8b.

A horizontal shelf 3f is supported from vertically-movable frame 3 and is positioned adjacent control panels 8b and 9b and moves vertically with respect to these panels as the frame 3 is moved up or down. A series of control switches Al to A9 are mounted upon shelf 3f adj acent panel 8b, while another series of control switches Bl to B9 are mounted on shelf 3f adjacent control panel 9b. These control switches may be of any suitable construction but we prefer Ito employ switches of the micro-switch type which may be operated by small mechanical movement of the operating member. One switch element and the mounting therefor has been illustrated in Figure 9. Each switch structure is mounted in a suitable insulating casing l which is pivotally mounted at Illa between suitable brackets l0b supported on a base plate 3io which is adjustably supported on shelf 3f. An voperating arm I0c is pivotally supported on the casing l0 and engages the operating pin ilid which extends out of the casing l0. 'Ihe upper end of the operating arm Hic is provided with a roller Ille which normally engages the inner face of the control panel 8b. A resilient stop is provided to engage the back of the casing i0 and to hold the arm iilc lightly into contact with the control panel. This resilient stop is preferably formed of a rubber ringer lllf mounted on a resilient support I 0g. Each group of switches is provided with its own base plate which is mounted on shelf 3f for adjustment to and from the associated control panel, for example, in Figure 8 the switches of the A group are mounted on base plate 3fa which is adjustable towards panel 8b.

panels may be formed in any desired manner, such as by embossing or prick punching the projections on the body of the panel, or they may be formed of separate elements secured to one face of the panel and adjustable along the path of travel of the associated switch operating element. The function of the switches which are operated by the control panels is to control the speed of dipping, and the spacing of projections P on the panels will be determined bythe particular shape oi' the molds being used. The object in controlling the speed of dipping is to move the mold into and out of the liquid at such speed that the line of contact of the liquid with the mold moves along the mold surface at a substantially uniform rate. In the case of a mold of the shape shown in Figure l1, a large number of steps of speed variation would be required to maintain a constant immersion rate, but a satisfactory approximation can be obtained in a relatively small number of steps. For example, in the case of the mold shown in Figure ll, the mold may be lowered at a relatively fast rate until it approaches the liquid level indicated by the line L-L, and then the lowering rate vis changed to a slower rate until the mold is immersed to the line a at which time the rate would be increased and maintained constant until the mold is immersed to the line b, and then a lower speed is established until the mold is 'lowered to the line d, where the mold is either stopped for a dwell period or it is reversed in direction `for withdrawal l from the liquid. On withdrawal of the mold from The" control switches preferably are in open posin It will be the liquid, the same variation in speed of withdrawal must be employed as in the case of immersion.

In Figure 10 we have illustrated a control panel with properly spaced projections for controlling the dipping of a mold form like that shown in Figure il. In this case, nine control switches are provided, and panel 8b is provided with nine projections, Pl to P9, for operating the nine control switches Al to A9 respectively, shown in Figure B. The number of control switches required will be determined by the number oi' speed steps required `for a particular shape of mold.

On the downward movement projection Pi is arranged to operate switch Al when the mold reaches the position with respect to the liquid level L--L shown in Figure ll. As the liquid level rises to the lines a, b, c, projections P2, P3 and P4 successively operate switches A2, A3 and A4, respectively, to establish the proper dipping sneedsand when the liquid level reaches the line d, projection P5 operates switch A5 to either stop the downward motion for a predetermined dwell period, or, as desired, to reverse the direction of movement and start withdrawal of the mold from the liquid. On the upward movement of the lvertically movable frame 3, projections PB, P'i

and P8 cause the successive operation ci switches .A6, A1 and A8 to establish the proper speeds izor Withdrawal. After the mold leaves the liquid, projection P9 operates switch A9 to establish a high speed of movementof the frame 3 to its upper position. The upward movement of the frame 3 is stopped by means of an up limit Vated starting button ST.

A .cuit for relay rent generator G as a source of current for driving motor 2 and this generator may bev driven from any suitable source of power. The armature Ga of the generator is connected to supply current to the amature 2a of the motor 2, through a circuit extending from armature Ga -through contact IIa on relay II. contact I2a on relay I2, through amature 2a, through carriage operated switch C8 when the moldcarriage is over tank' 8, or through carriage operated switch C8 when the mold carriage is over tank 8. through down safety switch DS, through up safety switch US and through contact Ila of relay I8 back to amature Ga. The generator field Gb and the motor field 2b", and the control circuits therefor, are separately excited from a suitable source of direct current represented by supply lines I4a and I4b. The energizingcircuit for relay I I is completed through normally closed up" limit switch which is mounted on frame I (see Figure 2) and is adapted to be operated to open pomtion by a nger ULSa carried by frame. 3 when this frame -reaches a predetermined position in its upward travel. The circuit ofrelay I I may also be c om-g pleted through normally open, manually oper- The normally closed "up safety switch US is also mounted on frame I and is operated .to open position by finger USa carried by frame 2 in case the limit switch UIS, fails to operate. The down safety switch DS is molmted on fram'e I as shown in Figure 2, and

ments control the value of the generator field current and thereby control the generator voltage which in turn controls the speed of motor 2.

A separate adjustable resistance is provided to iix the speed of the motorv for eachstep in the dipping operation.- N' l Since the speeds required for dipping in tank 8 may be diil'erent from the speeds required for dipping in tank 9, two sets of speed controlling resistances are provided, resistances .I to 88 being employed for tank 8 and resistances 8| to 88l for tank 8. 'I'he circuits through the various speed controlling resistances are controlled by a relay I0 having switch elements II to '88 inclusive controlled by a common operating member which is normally biased by a spring 38d to the position shown in Figure 12 where the resistance elements II to 98 are connected in circuit. Relay 80 is energized by a circuit connected to conductors I4a-I4b and controlled by a normally open switch.89 which is mounted upon frame I and adapted to be moved to closed position by nger C8a mounted on the mold carriage when the carriage is in position over tank 8. Accordingly,

when switch 39 is closed, relay 80 is energized and operates to shift the circuit connections to speed controlling resistances 8l to 88 and to break the is operated to open position by ringer DSa carried by cross-head 8b in the event that the reversing relayfails to operate. Theswitch DS is adjusted to .stop the downward-movement of the mold carriage before the molds reach the bottom of the tank. Safety switches DS and US remain closed during normal operation and are opened only in case of improper operation of the con- Itrol circuits.

. Relay I2 is normally mally SP.

The field 2b of motor 2 is supplied with ener- Sizing current from circuit I4a-I4b through the contacts of a reversing relay I5. Y A condenser 2C is connected in shunt to the eld winding to reduce the sparking at the contacts of relay I5.

In the normally de-energized positionof relay I5, the motor field 2b is connected in a direction to lower the mold carriage, energized, the carriage is energized through a circuit raised. Relay I5 is completed from conductor I4a through contact IIb on relay Il,

through relay I5, and through contact lia on relayV I8, back to conductor I 4b. A holding cir- I5 is completed through contact Iic andV resistance I5d. A manually operable two-position switch I1 is provided to by-pass safety switches US and DS in one position and vto energize relay I6 from conductors I4a-i4b in the other position, it being understood that switch I1 is normally open.

The generator field Gb is connected directly across conductors I 4a and I4b through the upper contact on relay HSd, which is known as the high-speed down relay, or the circuit for^` eld Gb. may be completed through any one of a number of adjustable resistance elements 8|, 82, 83, 84, 85, 86, 81, 88 when the mold carriage is in position over tank 8, or through any one of a series of adjustable resistance elements 9|, 92,

93, 94, 95, 96, 91, 98 when the mold carriage is in position over tank 9. These resistance eleand when relay i5 is Vcircuit, connections to resistances 9I`to 88 inclsive. 1

'Ihe circuit connectionsfrom relay switch elements 3l to 38 inclusive are controlled by normally open contacts on control relays 2l to 28 respectively. Relays 2l to 24 are employed to control the in or down speeds of dipping, and

energized 4through a norclosed, manually operated stop" switch lthese relays are supplied with -energizing current "through a common circuit extending from conductor I4a through contact llc on relay II, through the lower contact on transfer relay TR 46 to the four relay windings. 'I'he individual cire cuits for the relay windings are then completed through switch elements 4I, 42, 43 and 44 of a relay 40 (which is normally biased by spring 40a to the position shown in Figure 12) ,Y through control switches BI to B4, respectively, associated with tank 9, and from here the circuits are completed through a common connection, including switch-element 38a on relay 30, to supply conductor I4b. Relay ,40 is energized in parallel circuit relation with relay 3ll,whereb'y when the mold carriage is in position over tank 8, relay 40 is operated to transfer the energizing circuits oi' relays 2I to 24 from control switches BI, B2, B3, B4 to control switches AI, A2, A3,A4 associated with tank 8. The energizing circuit for transfer relay TR extends from supply conductor I4a through contact I Ib on relay Il, through the normally open contacts controlled by plate I 5b on relay I5, through the winding of relay TR and back to supplyfconductor I4b.

Control relays 25 to 28 inclusive are employed for controlling the out" or upward speed of the mold carriage, and these relays are supplied with energizing current through a common circuit extending from conductor I 4a through contact IIc on relay II and through the upperI contact on transfer relay TR to the windings of the four relays. The individual circuits for relays 26, 21 and 28 are completed through switch elements 46, 41 and 48 on relay 40, through control switches B6, B1 and B8 associated with tank l9, and from here the circuits are completed through a. common connection, including switch-element 30a on relay 30, to supply conductor I 4b. When relay 40 is energized, theA circuits for relays 28, 21 and 28 are completed through control switches assasic A9, A1 and A8 associated with tank 8. The energizing circuit for relay 25 is completed through contact |6b of relay I5 having an energizing circuit controlled by switch element 45 on relay 40 and by control switch B when relay 48 is de-energized or by control switch A5 when relay 40 is energized.

The energizing circuit for the high-speed down relay HSd is controlled through normally open contact Ild on relay and a'holding circuit for this relay is completed through a normally closed contact on relay 2| and a normally open contact on its armature. Holding circuits for relays 2| to 21 inclusive are completed through normally open contacts on each relay and through normally closed contacts on each succeeding relay. For example, the holding circuit for relay 2| is completed throughthe normally closed bottom contact on relay 22 and through the normally open upper contact on relay 2|. A holding circuit for relay 28 is completed through the normally open upper contact on this relay and through the normally closed contact on the highspeed out relay HSo. The normally open upper contact on relay HSo is connected to energize the relay HSd which in turn connects the generator field Gb directly across supply conductors IIa-|417. The energizing current for relay HSo is supplied over the same common circuit with relays 24 to 2l and is controlled by switch member 49 on relay 40 to complete the by shaft 53h when the motor 2 is running in a direction to raise the mold carriage. When the clutch coil 5|d is energized, contacts 5|a and 5|b are operated and are latched in operated position. Operation of contact 5|a opens the circuit to relay I3, while operation of contact 5|b closes the circuit to relay motor 5Ic. These contacts remain in latched position until the motor 5|c has counted off the dwell period and operates a latch member to release the contacts 5 la and 5|b.

Operation of the arrangement shown in Figures l to 11 will now be described, reference being had to Figure 12. The operation will be described for a process of forming molded articles from rubber. In this case, tank 8 would be provided with a coagulating or exhauster solution, while tank 9 contains the latex compound. It' will be assumed that suitable molds, such as those illustrated in Figures l, 2, 4 and l1 for forming rubber balloons, have been mounted in the rotary mold frame and the rotary frame is locked in its normal position by locking lever 6k engaging the notch on the arm 6g as shown in Figure 7, whereby the molds 5 extend downwardly in the position shown in Figures l and 2. The mold carria-ge 4a--4b--4c is now moved into position over the tank 8, and finger C8a operates to close switch C8 in the armature circuit connecting the generator with the motor 2, and also closes switch 39 circuit through control switch B9 associated with tank 9 when relay 40 is de-energized, or to complete the circuit through the control switch A9 associated with tank 8 when relay 40 is energized. Locking magnet. LM is energized from supply conductors |4af|4b through a circuit which is controlled by switch member 30h of relay 30 through a manually controlled switch 29 and through a normally open switch which is mounted on frame I and adapted t0 be operated to closed position when the mold carriage reaches a pre-determined position in its upward travel.

The energizing circuit of relay I3 is supplied from conductors closed contacts 5|a of a time relay represented in the rectangle 5|. This relay may be of any suitable construction, but simply by way of example, we have illustrated a relay of the type disclosed in United States Patent No. 2,175,865. This relay involves a normally open contact 5|b `for controlling the circuit to a motor 5 lc for driving the timing mechanism, and also a clutch coil VBld for connecting the motor to the timing mechanism and for operating contacts ila and 5|b to latched positions.

' The timedelay relay is energized from an alternating current circuit 52 which is controlled by switch element 80e on relay 30, the switch element 90o being in closed position when the mold carriage is over tank 9. 'The circuit through clutch magnet 5|d is controlled by a switch 53, which is responsive to the direction of operation of the motor 2, and also by a normally open contact |6c on relay I5. Switch 53 may be of any suitable construction, but, for the purpose of illus` tration, the switch has been shown as compris ing a pivoted switch element having a sector member 53a secured thereto and a rotary shaft 53h having frictional contact with the curved outer edge of sector 53a. Shaft 53h is driven from the motor 2, and the arrangement is such that the switch 53 is maintained in open position when the motor is running in a direction to lower the mold carriage, but is driven to closed position IIa-Hb through normally.

ythe common circuit to control switches AI, A2,

etc., associated with tank 8. Switch elements Nb and 36e are opened by relay 30, since the dip into tank 8 does not require a dwell period and does not require rotation of the rotary mold frame into vertical position. Relay I3 is energized and contact |3a is in closed position, but the generator-motor circuit is opened at contact I la on relay due to the fact that upper limit switch ULS is in open position from the previous upward movement of the moldcarriage.

Before starting the machine into operation, the operator will adjust the hand wheel 8c until the end of the indicator arm 8e comes in contact with the upper surface of the liquid in tank 8..

The indicator arm le is carried by the rod 8d which supports control panel 8b, and this adjustment involves a corresponding up or down movement of the panell 8b, whereby the control panel maintains a xed relation with respect to the surface of the liquid in the tank, and the control switches are thereby operated at the .proper positions in the cycle of movement of the mold carriage. While we have shown the indicator arm 8e as extending downwardly into contact with the liquid surface, it will be understood that the arm may extend below the surface and the point of the arm may be directed upwardly, so the proper adjustment of the arm is obtained by observing the small cone of liquid which forms around the tip of the pointer as it` begins to rise above the level of the liquid.

When all proper adjustments have been made, the operator depresses the starting button ST, which closes the circuit through relay to close the generator armature circuit, and also closes a circuit through relay HSd which in turn connects the generator field directly across conductors I4a and |4b. The generator G becomes Ato connect in resistance speedv fromA line c to.

24.- Operation of relay I8 circuit to transfer relay contacts controlled by plateA lib. Reversal of the is driven upwardly at a gizes runyexeited and drives the motor z at hign speed -in a direction to lowerthe mold carriage, and the initial movement of the carriage causes the closing o! "up"- limit switch ULS; The motor continues to run at high speed Vuntil control switch AI is operated by the projection on the control panel 8a, and this switch energizes relay 2| which opens the .holding circuit of relay HBd and closes "its own holding circuit through the normally closed contacts of relay 2 2. Relay 2| also completes a circuit for the generator held through resistance 8| which' preferably has been set at a value to give' a predetermined motor speed. Re-

ferring to Figure l1, controlswitch AI is' oper- .ated before the moldsreach the liquid level LL.

andthe molds are then lowered at a slow rate until the liquid level reaches the line ain Figure 11 when control switch A2 is operated by the control panel, and this switch energlzes relay 22 82 and disconnect relay Resistance 82 establishes a denite speed o1' dippingv until the liquid level reaches line b in Figure ,11.v At this time control switch VA3 is operated by the panel 8a, and this switch connects in resistance 88 and de-energizes relay 22. 'Resistance 83 establishes a denite dipping speed until the liquid level reaches the line c at which gizes relay 28. This establishes afproper dipping line d inv Figure 11, and

when the liquid level reaches tlielinedjcontrol switch A5 operates to energize relay is which in turn enersizes'reversing relay I8 to reverse Vthe motor-field 2b, and

also energizes relay 25 which connects in resistance 85 and de-energizesrelay closes the energizing TR through the upper motor field .2b causes reversal in the direction 'of rotation of the motor 2 and the mold carriage sistanceA 85. On the upward movement of the mold carriage, control switches A8, Al; A8 and A9 Vare operated byfthe control panel when the liquid level reaches thelines c, b, a; and LL respective1y, as shown in Figure 11,-te estabiish the proper speeds of withdrawal of the molds from the tank. Operation of control switch A9 enerhigh-speed out relay HSo which in turn energizes relay H Sd to fully excite the generator G and thereby drive the mold carriage at high speed to its upper position. The carriage continues to rise opened by the nnger Uisa, and this 'de-energizes until up limit switchULS is relay I Ito open the generator-motorecircuit.

1Ii? a second dip is required, another cycle may be carried out by simply pressing starting button 'I'he next step in the'moldi'ng operation is to move the mold carriage Ia-lb-Ic into position over tank 9, and this results in opening of switches C8 and 39, and the closing of switch C9. The opening of switch 89 de-energizes relays 30 and 40 to restore these relays to the position shown in Figure 12 whereby the control circuits are switched from the control switches associated *with tank 8 to the control switches associated with tank 9, and resistances 9|, 92, etc., are connected in circuit instead of resistances- 8|, 82,

wheellcuntilthepointer mrfaeeofmeistexintenk Upon prv-sing the starting button Sl', relays Ilfr and'HSd are again energized and themold carriage is lowered at high speed Auntil'the mold reaches the lposition Vshown in Figure 11 with re- Y time control switch A8 operates to energize relay A24 which connects in resistance 84 and deeenerspect to the liquid level mand at this time control switch BI operates to establish a slower dipping speed until the liquid level reaches the line a in Figure 11. The dipping operation from this point on until the liquid level reaches the line d.

is the same as described above in connection with tank 8. During the downward movement oi' the mold carriage, the switch 88 is maintainedl at open, position by rotation of the motor 2. When control switch B8 operates relays I8 atthe point d in Figure 11, relay I8 energizes reversing relay I8 to reverse the motor 2 as explained hereinbei'ore.

and the initial reverse movement oi' motor 2 causes switch 83 to move to closed position and to therebyv energize clutch magnet SId of time delay relay 8|. Magnet 5Id opens contact 8| a to thereby de-energize relay I8 and also closes contact SIb vtoenergize relay motor 8Ic, and these' contacts are latched in operated position. Thus the motor 2 is stopped in a position where the liquid level is approximately at the line d in Figure 11, and the molds are allowed to remain immersed in the Vlatex for a predetermined time which may be controlled by the setting of the'relay 8|.V 'The purpose of using the rotation. responsive switch .53for starting the dwell period is to insure starting of the dwell period at a time when there -is Speed determined by reno possibility that the momentum of the driving l during the dwell period.

As soon as relay motor IiIc counts oil' the dwell motor 2 will cause .coasting of the mold carriage time, contacts 5Ia and 8|b are released and returned to their normal position to re-energize relay I3 which in turn closes the generator-motor 1 circuit to start raising the mold carriage. During upward movement of the mold carriage, control sw'itches'BG, B'I, B8 and B9 operate at proper times to establishthe desired speeds of withdrawal, andthe upward movement of the carriage is stopped by opening of the up vlimit switch ULS Vwhen the carriage reaches its upper position.' At the same time, switch is operated to energize locking magnet LM which releases locking barA 6k, and the rotary mold frame moves from the position shown in solid lines in Figure 2 to the 4position shown in dotted lines in Figure 2. The molds are allowed to stand in this position for a certain period in order to prevent the formation of thickenedtips on the dipped ar ticles due to the action of gravity on the coat.

ing when themolds are in the full line position shown in Figure 2. VWhen the molds are rotated to' the dottedline position, for thickened articles.

there is no tendency portions to form on theends of the 'l It is not always necessary rotate the molds 'in the manner described immediately above, and s in this case the switch 29 may be left in open position so that the magnet LM will not be energized. Also, in case it is desired to have the molds rotated to up position over both tanks, the switch element 30h may b e dispensed with and the circuit to magnet LM may becompleted through switches 29 and 58 independently of the relayV 30.'

etc. Also, the circuits to locking magnet LM and to the time delay relay 8f are rendered effective. The operator makes proper adjustment of nana rs Switch blade 30a instead of relay 38, or it may be omitted entirely,

and the leads controlled by this switch may be permanently connected to supply conductor IIb.

ae'isiusuouemgthe may be operated by relay-8|) Since relays 30 and 40 are energized in parallel and operate simultaneously, vonly one relay may be employed to control all of the contacts which are now controlled by relays 30 and 4U.

Relay I2 may be omitted, and stop push button SP may be inserted in the energizing circuit of relay i3. l,

A separate relay need not be employed to perform the function of transfer relay TR, but the contacts which are controlled by this relay may be controlled by relay l5.

In the arrangements shown in Figures 13 to 28, the same reference numerals are employed to indicate elements havingthe same functions as corresponding elements in Figures l to 11.in

elusive.

In Figure 13 the tank 8 is mounted upon hydraulic lift H8 for vertical adjustment through a limited range, the tank being positioned within an opening in the iioor F of a suitable building. The tank 9 is also mounted for vertical adjustment upon a hydraulic lift, H9. Lifts H8 and H9 may be pneumatic lifts if desired, and it will be understood that these lifts are operated from a suitable source of fluid under pressure and by suitable control devices to adjust tanks 8 and 9 to any desired vertical position within the range of movement.

The dipping tank 9 must be maintained at a predetermined level or elevation during the dipping operation, andfor this purpose we employ an adjustable finger 54 mounted in the path of movement of the rim of the tank as shown in Figure 14. The finger 54 may be supported in any suitablevmanner for vertical adjustment such as by the index arm 54a mounted for'vertical sliding movement on a suitable frame and being adjustable vertically by means of a lead screw 54h provided with an operating wheel 54e. The free end of the index arm 54a is provided with an index pointer co-operating with a suitable stationary index scale 54d. For any given mold, the index arm 54a will beset in a predetermined position, and the tank 9 will be maintained in contact with the lower end of finger 54. For molds of short length, the arm Sla will be adjusted in the upper I of the tank 9,'the linger may extend over the tank and be maintained in contact with the upper surface of the liquid in the tank.

Tank 8 may also be provided with an arrangement for setting the tank at a predetermined elevation in lthe same manner as tank 9.

, Mounted directly above each of tanks 8 and 3 is dipping apparatus generally like that described in connection with Figures 1 and 2- Since this apparatus is identical for both tanks 8 and 3, only one installation will be described. The arrangement includes a fixed frame I which supports motor 2 for driving vertically movable frame 3 upwardly and downwardly through lead screw 3c, cross-head 3b and guide rods 3a. A pair of horizontal track elements 3d and 3e are supported on opposite sides of vertically movable frame 3 by a construction illustrated in Figure l5, this construction being Asomewhat different from that shown in Figures l and 2. A mold carriage I is mounted for movement on track elements 3d and 3e by suitable wheels 4e mounted at the fourcorners of the carriage.

For the purpose of supporting the molds from the carriage I, a horizontal frame 4c is supported upper position of rest.

from the carriage 4 below the track elements 3d and 3e as shown in Figure 15. The molds 5, of a different shape from the molds shown in Figures 1 and 2, are secured to a suitable frame generally indicated at 5F which is detachably secured to horizontal frame 4c by means of a number of clamping hooks 4d having their threaded shanks extending upwardly through suitable guide bearings `in frame 4c and provided with hand wheels 4f for clamping the frame 5F to the frame lc, see Figures 17 and 18- The mold carriages are brought into position 'over tanks 8 and 9 by means of an overhead trolley rail R- mounted on suitable supports. The rail R is provided with a gap over each of the dipping tanks, and a section Ra of the rail;`

carried by. vertically movable frame 3, is provided to bridge the gap when the frame 3 is in its upper limit of travel for normal operation. Each mold carriage I is provided with two sets of swivel-mounted wheels 4g and Ih for supporting the carriage on rail R when the carriage is being brought up to and moved away from the tanks. For example, in the case of the two mold carriages shown at the extreme right and left ends of Figure`13, the carriages are being supported on rail R by wheels 4g and 4h, while the two carriages which are located immediately above tanks 8 and 9 are supported on track sections 3d and 3e by wheels 4e. Track sections 3d and 3e are positioned to take the load of the mold carriage and to relieve the load from wheels 4g and 4h when the mold carriage is in position over either tank. By this arrangement, each mold carriage has four points of support which are widely separated and will thus prevent swaying of the molds during the dipping operation.

For the purpose of guiding the mold carriages into proper position within the vertically movable frame above each tank, stationary extensions of horizontal rails 3d and 3e are provided in front of tank 8, to the rear of tank 9, and also in the space between the two tanks. One rail extension in front of tank 8 is shown at 3d' in Figure 13, the extension between the two tanks is shown at 3d",and the rail extension at the rear of tank 9 is shown at 3d"'. These stationary rail sections are all at the same level as the rails 3d and 3e carried by the vertically movable frames when these frames are in their proper Accordingly, when the mold carriage is moved on to rail extensions 3d' and 3e', the weight of the mold carriage is taken by these rails and relieved from rail R. When the carriages are moved beyond rail extensions 3d'" and 36"', the Weight of the carriage is again taken by rail R which leads into a drying chamber or tunnel DT.

It will be understood that dipping mechanism of the type shown in Figures l and 2 may be used in the system shown in Figure 22.

Provision must be made to keep the mold carriage centered in the vertically-movable frame 3 and to prevent the carriage from .rolling out o1' the frame during the dipping operation. For

this purpose two latch elements 19a and |911 are pivotally supportd in slots formed in and near the ends of rail 3d on the frame 3, and these latch elements are positioned. to engage the front and rear wheels 4e of the mold carriage l and to preanais. sswmueeemtnentenairemnsea witharmlia'andllbandeachiatch isbiasedtowardsitshtchinlolltibypnl Itc holding arms lla' and IIb' against aiixedstop ltd. By this arrangement, the latenciement llbmaybebythewcightotthe moldcarriagcasitisrollcdintotheverticallyv accasiomovable frame 3. butas soonas the carriagev comes into center position, the latches willprefrom balngmoved in either direction. The iocreleasing latch a,sothatthecan'iagemaybemoved outoi the frame 3, involves a'hand-wheel 2l mounted onarotaryshaftzlajournalledonframeland havingacrankarmllbsecuredtntheend thereof. A link element llc connect'sthe arm 20h with the arm isa' onlatch lla. Thehand wheel 23 extends out into a position within convenient reach of the operator. By a-partial turn o! Y wheel n me clockwise direction, es' seen in Fisure 17, the latch Mais moved to depressed position, and the carriage 4 maythen be rolled out of the trame 3. Y

Anormally open centering switch CS is mounted on vertically-movable frame 3 and is adapted to be operated to closed position by a cam-finger CSa carried by mold carriage 4 when the carriage is in its proper centered position on' the frame 3,',as shown in Figure 16. This switch is connected inthe generator-motor amature circuit and Aprevents operation of the motor unless a' moldcarriage is :properly centered in the Y vframe 3. e

Each vertically movable dipping frame is vdriven by a separate motor which is controlled from a' suitable control p anel of the' same type as shown in Figures 1 and 2, but in Figures 14 and, 15, the Vcontrol panel is mounted to move with the dipping frame 3 while the control switches are supported on a stationary bracket.

In Figures 14 and 15 the control panel sb for the compound tank is shown supported at one side of the vertically movable frame 3, and the series -of control switches B are supported on stationary bracket I8. As shown in Figure 19, the switches are suppOlted in generallyV the ysame mannerlas ataconstantrateselectedtodrythearti clesor-dryandvulcanizethemiidesired.'

.Aiterthe carriagesleave the dryingtunnel Ul',theyare eonveyedonrail'R, (seeFigure 22) toast'ripping machine generally indicated atSM (onespecincformbeingillustrateldinligures thecarriagesarethenconductedbyrailltalong apath which passes over a'washing tank WT, thenoverarinsingtankRTandarcthenreturned for reuse in subsequent cycles. A numberthe 'articles-have been stripped from the molds,

o! mold carriages 4 are shown in various positions along the closed path oi' travel of the carriages in Figure 22. As the mold carriages pass over washing tank WT and rinsing'tank RT, the rail R is positioned at a lower level to permit 'the molds 8 to become immersedin the washing and rinsing liquids so the molds will be thoroughly clean for a Vnew dipping operation. A suitable conveyor system is employed for conveying thel mold carriages through these two tanks.

The track section located above the stripper shown in Figure 22 is formed as a spur whereby eachvmold carriage is reversed end-forend as'it leaves the stripper and proceeds to the washing tank. With this arrangement, the carriages must be provided with two symmetrically located cam elements to operate the centering switches where the'switches are not located in the center oI-.the track. Il desired, the stripper may be located under'a section of the track included directly in the track loop, whereby the carriages always run with the same end forward.

The control systems for the two driving motors associated with the dipping frames for tanks s and s in Figure 13- are fundamentally the same as the control system shown in Figure 1 2. In the case ot tank 8, if it is not desired to have a dwell period at the bottom position of the dipping frame, the time relay 5I and relay I3 are omitted. Also, since each motor has its own control panel.

relays 3l and 40 are omitted, and only one set oi 4they are supported on shell 8f inFigures 1 and 2, so that the operating' elementsiof the switches may be actuated by the 'projections on panel 8bA as the panel movesup and down. It will tbe understood that the panel 8b. is removable and a panel having the desired arrangement of projectionsnay'be readily mounted in positionior operating the controlV switches. Also, while only seven control switches are shown in the arrangement illustratedv in Figures 11i, 15 and 19 to `control the relatively simple molds shown in Figure 4'20, any desired number of switches may be. em-

' shapes of molds. Y

In operation of the arrangement shown in Figures 13, 14 and 415, the mold carriages with molds properly attached are brought in from the right ployedrfor controlling the' dipping rate of other speed controlling resistances corresponding to res'istances 8l to 88 will be used. Controlswitches lBI toB8 are not provided for tank 8. A1so.lock

ma'gnet LM and its controlling circuit is Y omitted for both tanks. Otherwise, the control circuit for'tank corresponds to that shown in Figure 12, except, that, Afor the simpleform of mold shown in Figures 13 and 20, only six speedcontrolling .resstances and seven control switches are used. In this case,'relays 2 4 and 28, control switches A4 and A8, and resistances 84 and 8l.' yare not required' and may be omitted. It will be understood that up limit switch ULS and safety switches'DS and US are provided'to-control the operation vof the dipping in the same manner asin Figures lj-and 2*,and centering. switch CS serves the function Vof switch AC8 1n V Figure 12. Switch C9 of Figure 12 is Vomitted for tank8 of Figure 13.

Y LM and its circuit;

The control circuit for the motor which con' trois the `dipping in tank 9 corresponds to the arrangement shown in Figure 12, except that the following elements are omitted: locking magnet relays illand 40; switches 39 and C8; control switches Al to A4 and resistances 8| to 88. Also, for the simplemold shown in Figure 20, relays 24 and 23, switches B4 and B8. and resistances 94 and 88 are not required and may be omitted. As in the case of tank 8, limit switch ULS and safety switches DS end US are also provided for tank and

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