US1554241A - Plant for treating metal articles - Google Patents

Description

1/wanton 3 Sheets-Sheet 1 Sept. 22, 1925.

D. L. SUMMEY PLANT ToR TREATTNG METAL ARTICLES Filed July 28, 1923 ou mW Sept. 22, 1925. 1,554241 D. L. suMMEY PLANT FOR TREATING METAL ARTIcLlzs Filed July 28, 1923 s ysheets-sheet 2 vwemtoz sept. 22, 1925.

. D. L. SUMMEY PLANT FOR TREATING METAL ARTICLES Filed July 28, 1923 3 Sheets-Sheet 5 5441x114 coz Patented sept. z2, 1925.

i UNITED sTArEs PMENT OFFICE.

DAVID L. SUMMEY, F WATERBURY, CONNECTICUT, ASSIGNOR TO SCOVILI MANUFAC- TUBING COMPANY', OVF WNATERBURY, CONNECTICUT, A. CORIORATION 0F CONNECTI- CUT.

PLANT FOR TREATING METAIJ ARTICLES,

application mea my es, iaas. serial No. 654,294.

To all whom it may cof/warn."v

Be ,it known that I, DAVID L. SUMiIEY, a citizen of the United States, residing at Waterbury, county of New 'I-Iaven, and State of Connecticut, have invented certain new and useful Improvements in Plants for Treating Metal Articles, fully described and represented in the following specifica-` tion and the4 accompanying drawings, forml0 ing a part of thesame. A w

This invention relates to plants for treating metal articles. `More particularly the invention relates toplants for annealing, cooling and finishing metal articles.

It is the principal object of the invention to provide a plantl for treating metal articles efliciently and leconomically and with a minimum manual labor requirement.

With this general object in view the linvention consists inthe combinations, details of construction and arrangements of parts which will first be described in connection with the accompanying drawings and then more particularly pointed out.

* In the drawings- Fig. 1 is a view in vertical longitudinal section of one end of ametal treating plant constructe'd in accordance with the invention' Fig. 2 is a view in side elevation showing the other end of the plant; v

Fig. 3 is an enlarged transverse sectional view' through the annealing furnace;

Fig. 4Ais a bottom plan view of part of the conveyor'chain;

Fig. 5 1s a sectional views7 taken onk the line* 5-5 of Fig. 2;

Fig. 6 is an enlarged view in side elevation of the automatic charging mechanism;

Fig. 7, is a similar View, withparts in section, of part of the charging mechanism in a different position; i

Fig. 8 is a sectional view taken on the broken line 8-8 of Fig. 6;

Fig. 9 is a sectional View taken on the line 9-9 of Fig. 7 and, Fig. 10 is a detail view showingA in section part of the charging mechanism. Vhile plants embodying the invention are- 50 capable of a variety of uses, the plant here shown is particularly adapted to the treatment of brass shells or cups. In making various articles of brass, a shell is drawn from vbe heated in an a plate or other blank. The drawing operation may produce shells. which go directly tothe machines that form the iinished pro-- duct or the shells may require further ldrawing. In either case, following the drawing operation the shells are treated, this treatment including annealingpcooling, pickling and other finishing operatlons.

are annealed or otherwise treated in a furnace 11, here shown more or less conventionally. The furnace shown as an example comprises a main housing 12 having a heating chamber 13 and a paralleling chamber 14 extending longitudinally therethrough. This main housing may be of any suitable construction and the heating chamber 13 may suitable manner, for example, by electric resistor elements such as .shown in a copending application of this ap`- plicant, filed July 28, 1923, Serial No. 654295. Iflde'sired the second chamber may be heated also. At one end of the furnace, the left Referring to the drawings, the articles" end in Fig. 1, is a supplemental housing hood 15 which encloses a charging chamber 16 which communicates with'the longitudinal chambers 13, .14. At the other end of the furnace a supplemental housing hood 115 encloses a discharge chamber 116, also. communicating with the longitudinal chambers. As here shownthe hood 15 rests directly on `the furnace foundation 1() and the discharge chamber 116 is sealed at the bottom by means of a cooling tank to be described.

There is provided means for transporting i the. articles to beptreated through the furf,` nace at such speed as to enable the heat treatment, such as annealing, to be accomplished. As here shown as an example, extending tihrough, the heating chamber 12 are a pair of'rails 17 on which slide conveyor buckets 18.' Each bucket has on one side a `pair of perforated lugs 19 and on the other side a pair of perforated yokes 20. lugs of one bucket are inserted in the yokes ofthe next bucket and suitable pivot pins 21 passing through the alining perforations connect the buckets to form an endless conveyor chain. The bucket bottoms have guide The Y lugs 22 which coact with the rails (Fig. 3)

to keep the chain properly positioned. At the charging end of the furnace the buckets` pass-over two complementary hexagonal pulleys 23 located in the charging chamber l5 and mounted on a shaft 24. As appears in Fig. 1, the rails 17 extend into the charging chamber to cooperate with the pulleys so that the buckets can pass from the uppermost faces of the pulleys directly onto the rails. At the discharge end of the furnace, the bucket chain passes over two hexagonal pulleys 25 located in the discharge chamber 116 and mounted on a shaft 26. As shown in Fig. 1, the rails 17 extend outwardlytoward the pulleys 25 so that the buckets can pass directly from the rails to the uppermost faces of the pulleys. As shown in Fig. 8, the faces of the pulleys are shouldered, as at 27, to cooperate with the guide,

lugs 22 of the buckets. From the lower part of pulleys 25, the inverted buckets pass onto rails 28 located in the return chamber 14, the rails 28 extending into the charging chamber 16 and the inverted buckets passup around pulleys 23 to take conveying position again. To drive the' bucket chain, as here shown as an example, on the shaft 26 is a gear 31 meshing with a pinion 32 on a shaft 33. Also on shaft 33 is a worm gear 34 meshing with a worm 35 driven by a motor 36. The motor is operated and the gearing proportioned so as to move the buckets through the lheating chamber 13 at a speed to accomplish proper heating of the articles under A treatment, this movement, in the present embodiment, being continuous.

There is provided means for automatically delivering the articles to be treated to the furnace, and in constructionspf the type above described, the articles may conveniently be delivered to the buckets while they are in the charging chamber 16. Further, with constructions embodying bucket conyveyors as above described, the charging means may conveniently include a meas- When the uring hopper. Although capable of various constructions, in that here illustrated as an example, above the pulley shaft 24, so as tobe `above a bucket as it rst takes upright position, is an opening 37 in hood 15. On the hood adjacent this opening is a hopper housing 38 open at the top. Partly in the housing 38 and extending into the chamber 16 through opening 37 are two complementary gates 39 mounted to swing toward and away from each other. To this end, each gate has a hub 40, one being pinned to a rock shaft 41, the other to a rock shaft 42. gates are swung to closed position, their lower edges abut against a suspended sill 43. At the ends of the gates 39 are wings 44 which, with the gates, enclose a V shaped space when the gates are'closed. As appears in Figs. 6 and 8, the hopper housing has guide walls 45 extending upwardly from the hubs 40 of the gates and gulde flanges 46 extending upwardly from the wings 44, so that articles supplied to the open top of the housing are properly confined. As will now be apparent, the gates 39, wings 44 and part of the housing 38 form a hopper of a given capacity and the contents may be dumped upon swinging open the gates. In the present embodiment, this given capacity is substantially the capacity of one conveyor bucket.

While the hopper may be filled in any suitable manner, as here shown as an example, above the open top of the housing 38, is a bin 47 having a funnel-shaped lower portion and a pivotally-mounted bottom door 48. This door may be swung downwardly by means of a handle 49 to the broken line position of Fig. 1. In this position, the door acts as a chute to guide the articles into the hopper. lVhen the hopper is filled the door is closed, closing movement being aided by a counterweight 50. The bin may be kept supplied with articles by means of a dumping barrel 51 on a hoist 52.

As will now be apparent, when the gates 39 are swung apart to ope-n the hopper, the hopper contents can drop by gravity into a bucket. Vhilc the gates may be opened in any suitable manner, in constructions embodying the invention to the best advantage, the operation of the opening means is Vcontrolled by the relative position of the buckets. For example, there may be provided means tending to open the gates, a latch element for preventing operation thereof and an escapement mechanism for tripping the latch element as each bucket takes a receiving position below the hopper. Although capable of various constructions, as here shown as an example, mounted on the rock shafts 41, 42, are intermeshing segmental gears 53. The shaft 42 extends outwardly from the housing 38 and secured to the extension is a rocker arm 54 having a weighted lower end 55. -W'hen the gates are closed, the weight portion 55 of arm 54 is raised above its center of gravity and is normally latched in such position to hold the gates closed. To this end, as here shown as an example, below the weight portion 55 of arm 54 is an arm 56 pivoted to a bracket 57 on hood 15 and having a stop lug 58 which, in the latching position of the arm, holds the weight portion 55 of arm 54 raised (Fig. 6). The arm 56, at the end opposite its pivot, is mounted on a piu 59 carried by a block 60 slidable up and down in the bracket 57. The block 60 is normally connected, by means to be described, with a second block 61 also slidable in the bracket 57. Vhen the connected blocks 60, 6l are moved down, arm 56 is lowered suliciently to trip lug 58 from latching position. This frees the weight portion 55 of arm 54 which swings down under gravity until stopped by a lug 158 on arm 56, thus rocking shaft 42. Through gears 53, shaft 41 is simultaneously 70, it rocks arm 65 the next l shown as an example,

. 75 adapted to hook over a "end of the pulley dog riding up just described, in the present embodimentV the second block 61 is connected by an adjustable link 64 with a-lever arm 65 mounted on a rock shafti66. Also is a dog 67 riding on an escapement wheel 68. This escapement wheel is mounted on the 69 located outside hood 15 and in which the shaft is journaled. The escapement wheel has a number of dog-elevating teeth70 equal tothe number of pulley faces, in this instance, six. The dog is held to its duty by means of -a spring 71 connecting lever arm `65 and part of the bearing 69.

Referring more particularly to Fig. 6, as the pulley shaft 24 rotates, the escapement wheel 68 rotates in clockwise direction, the the successive teeth. As the dog 67 crops oil the high point of a tooth shaft 66 and thus swings lever down, which, through link 64, pulls down the blocks 60', 61, to trilp the latch lug 58. The escapement wheel is so arranged that the gates are openedwherra bucket is in position below the hopper to receive acharge, as above described.

,After an operation of the latch-trippingmechanism link 64 will be slowly moved upwardly as the dog 67 starts to ride up tooth of the escapement wheel. Means is provided whereby the hopper gates can be closed and the latch reset as soon as a charge has been delivered and regardless of the dog 67. To this end, as here on the lower block 61 is pivoted a trigger 74 having a catch upperl block 60. Between the two blocks is a spring 77 tending to separate them. When the parts' are in. weight-latching position Y(Fig. 6), the trigger 74 is hooke over lug 76 and the two blocksl 60, 61 are, in effect, a unit and they move down as a. unit under the pull of link 64 above described. During this movement, however, and.' after the latch lug 58 has been tripped, trigger 74 strikes an adjustable trip screw 78 on the bracket 57 and the trigger is swung to remove its catch 75 from lug'7 6 (Fig. 7). Thereafter, the upper block 60 is fre/eJ to move back to former position regardless of the lower block.

To close and re-latch the gates, the operatorn swings the rocker arm ,54, thus rocking on this rock shaft' shaft 24 beyond a bearing 'they cooling means.

lug 76 on the shafts 41, 42 in the reverse direction and swinging the gates to closed position. Thisv movement is aided by a counterweight 142 on the4 rock shaft 42. This reverse `movement of the rocker arm 54, of course, again raises the weight 55 and the block 60 moves upwardly under the force of 77 to reset the arm in a position for its lug 58 to latch the-weight in raised position. The hopper may now be refilled' with another measured charge for the next bucket.

Meanwhile, during the rotation o-f the pulley shaft 24 and its escapement wheel, the dog 67 This dog movement rocks shaft 66 and so pushes up link 64 to elevate block 61. As soon as the block has been raised sufiiciently to move the trigger away yfrom the stop screw 78, the trigger is freeto swing back to normal position, a spring 79 tending to hold it lin such position. Upon further movement of the block 61, the trigger catch 75 slides over lug 76 and the two blocks are again hooked together. A pin and slot connect-ion 80, 81, between the trigger and the block v61 limits the trigger movements. With the construction described, the operhas been riding up the next tooth.'

ator has plenty of time to close the hopper, n

:be employed.

After a bucket receives its charge, the conl ltinued conveyor movement carries the bucket along the rails 17 into and through the heating chamber 13 where the charge is annealed or otherwise treated, as above described.

There is provided means for cooling the heated articles and means for automatically delivering the articles from the furnace to Although capable of various constructions, in that here shown, extending under hood 115 .and into chamber 116 is a tank 85 for containing a cooling liquid, for example, water, part of the tank being ylocated under the point! where the buckets turn down over pulleys 25. A's the buckets approachi an inverted position, the contents are automatically dumped out and drop by 'gravity into the liquid in "the tank;`

toward the tank. Shells some- -130 j suitable manner.

water sprays from pipe 86, however, by filling the shells and driving out the air, cause them to. sink.

There is provided means for automatically delivering the articles from the cooling means. As here shown as an example, extending into the tank 85 is an endless conveyor belt 87 which passes around a pulley 88 and over guide rollers 189. The pulley 88 is located near the bottom and inner end of the tank'so that the upper strand of the belt extends well under the discharge chamber and well below the liquid level. This upper strand is arranged at such an inclined thatit emerges from the liquid out.- side of and beyond the hood 115.

The beltis driven in any suitable manner. A. shown, the belt passes over a drive pulley 89 mounted on a shaft 90 supported on a standard 100. 0n this shaft is a worm gear 91 meshing with a worm 92. The latter is driven through gears 93, 94 from a motor 95. The belt is provided with cleats 96 for engaging the articles and as the upper strands moves upwardly the articles in the. liquid are taken by the belt and conveyed thereby out of the liquid to a point removed from the furnace and tank.

There is provided means for concentrating the articles discharged from the bucket in a space adjacent the rise of the conveyor belt. As here shown as an example, below the path of the falling articles is a guiding funnel 97 which extends into the liquid with its bottom edge just above the belt. As the articles fall into the liquid or confined within the space embraced by the funnel and so prevented from drifting about to points where the rising belt would not reach them.

The invention, in its entire-ty, includes finishing means to the action of which the articles are automatically subjected after delivery from the cooling means. This finishing means may include pickling, soda applying and other finishing operations. Although capable of various constructions, in that here shown as an example, adjacent the point where the belt. 87 turns down over the pulley 89, is located la gravity feed chute 99 which receives the articles as they automatically fall from the belt and conducts them to the end of a long finishingr drum 101. This drum is rotatably suspended by a plurality of circumferential rings-102 riding in pairs of oppositely disposed grooved rollers 103. It is rotated by means of chains 104 running over sprocketsl 105, the chains being driven in any Vithiin the drum ,'is a. screw conveyor element 106. As the drum rotates, the articles are caused to pass along the same and during such passage are given various finishing treatments.

Below the forward end of the drum is a temperatures.

tank 107 for containing a pickling liquor. On the drum, positioned to pass through the pickling tank as the drum rotates, is a scoop 108 which scoops up some of the liquor on each rotation. This liquor is delivered to the interior of the drum through a series of holes 109 in the drum wall located radially in line with the scoop. Vhen the scoop reaches an upright position the liquid carried up thereby fiows by gravity through the holes 109 into the drum and so over the articles. Beyond the holes 109 and above the tank 107 the' drum has a belt of holes 110 extending all the way around the drum and through these holes the pickling liquor flows back to the tank 107. Beyond tank 107 in the embodiment illustrated is a wash-water ta.nk 111 and the drum has a scoop 112 like scoop 108, the wash 'water being supplied and removed in a manner identical with the circulation of the pickling liquor. Beyond the Wash water unit is a soda unit 113 for supplying a. soda solution to the articles. This unit is identical with the units described except that the scoop and bands of holes are narrower, as appears in Fig. 2. Beyond this soda unit is a soap solution unit 114 for treating the articles with a soap solution. This unit is identical with the soda unit. As the articles progress through the drum they are first pickled, then washed, then treated with a soda solution and then with a soap solution. Finally they are dried. This may be accomplished in any suitable manner. In Fig. 2 two drying units 115 are illustrated diagrammatically. Beyond the drying units, is a delivery chute 117 by which the articles may be discharged.

In the plant described, certain of the metal furnace parts aregqnade of a. material capable of withstanding continued high In case heating elements, such as above referred to are used, namely, nickle-chromium alloy resistors, the metal furnace parts may conveniently be made of nickle-chromium alloy also, thus having the same heat resisting characteristics as the heating elements. In the plant here shown, the bucket chain, the upper rails 17, and the discharge pulleys 25 are made of nickle-chromium alloy.

To review the operation, motor 36 rotates, through the gearing described, the pulley shaft 26 and so drives the conveyor chain, the upright buckets moving from the left to right, as viewed in Fig. 1. Assuming that the hopper contains a charge, when a bucket reaches upright position, as illustrated bv the bucket shown in section in Fig. l, the dog 67 drops off the high point of a tooth of the escapement wheel and causes tripping of the latch lug 57 as above described. Veight 55 b'eing released, swings down under gravity and rocks shaft 42, thus causing the hopper gates to swing open. Thereupon the measured charge drops by gravity into the slowly moving bucket; Meanwhile, vtrigger 7 fi has been operated to permit separation of the two blocks 60, 61 and the operator swings the gates to closed position by means of lever 54, whereupon the latch will be re-set. The operator then opens the bin door and a new charge slides into the hopper. As the escapement wheel rotates, the latch-tripping parts are returned to their former positlon as above described.'

y Continued movement of the filled bucket carries the same through the heating chamber 13 for the heat treatment, for example,

annealing. As the bucket turns down over the pulleys 25 in. the discharge chamber 116 the articles are dumped out and fall into the liquid in tank 85 where they are quenched. The emptied bucket continues its course and slides, inverted, along the rails in the returnchamber 111 until it passes up around pulleys 23 to its original charging position. With an endless conveyor moving in a closed furnace there is a material economy inl heat requirements and. with a continuously moving conveyor excessive motive power requirements are avoided.

Meanwhile the articles discharged into the cooling tank are kpicked up by the belt- 87 and carried to a point'removed from the tank where they drop into chute 99 as the kbelt passes down over pulley 89. The belt 87 may be run at such a speed as to remove substantially all the charge of one bucket before the next bucket dischargesl it loa-d.

The chute 99 directs the articles into the finishing drum 101 where they are moved along by the rotation of the screw conveyor element 106. In the drum they are sub` jected to the action of a pickling liquor,

washed, treated by a soda solution and a soap solution and dried. The pickling liquor removes the scale; the soda` solution serves to neutralize such pickling liquor as may remain after washing, andthe soap solution assists in neutralizing any traces of pickling liquor and leaves a film which, when dried, prevents tarnis'hing and assists passage of thelarticle in the next drawing operation. The articles are finally discharged from the drum by chute 117 which may direct them to any suitable receptacle or conveyor.

The` plant above described is capable of` suitably` eecting the treatment of metal articles and particularly treatment following a drawing operation and in preparation for a subsequent drawing or forming operation. The plant Vis adapted to effect this treatment in an elcient manner and without harm to the articles. Furtherfthe entire operation from the time the articles are delivere'dto the hopper to the discharge from the finishing drum is automatic.

Certain features here shown are claimed What I claim is: 1. In a plant for treating metal articles, the combination with a heating furnace, of means for automatically delivering the articles thereto, a cooling tank, a conveyor for transporting the articles through they furnace at a rate to enable the heat treatment to be accomplished and delivering them autoin the copending application above referred maticallyto the cooling tank, a conveyor for I automatically delivering the articles from the cooling tank, and finishing means, including means for applying a picklin liquor, then washing, then applying a so la solution and a soap solution, to the action of which the articles are automatically subjected after delivery from the lcooling tank..

2. In a plant. for treating metal articles, the combination with a heating furnace, of means forautomatically delivering the articles thereto, a bucketk chain for conveying the articles through the furnace at a rate to 1 enable the heat treatment .to be accom-v plished, pulleys over 4which said chain passes, a cooling tank located below one pulley and into which the articles may fall by gravity as the buckets pass' over saidpulley, a con- A are automatically subjected.

3. In a plant for treating metal articles, the combination with a heating furnace, of an endless conveyor for transporting the articles through the furnace at a rate to enable the heat treatment tofbe accomplished,

-ickling liquor, a washingY pulleys over which said conveyor passes, a f

cooling tank located below one pulley and into which the articles may fall by gravity as the conveyor passes overl said pulley, "a conveyor for automatically vdelivering the articles from the cooling tank, and finishing means to the action of which the articles are automatically subjected after delivery from said last named conveyor. j j

4. In a plant for treating metal, articles, the combination with a heatingfurnjace, of means for automatically delivering the articles thereto, a cooling tank, a conveyor for transporting the articles throughthe furnace at a rate to enablethe heat treatment to be accomplished and delivering them automatically to the cooling tank, a conveyor for automatically delivering the articles from the cooling tank, and finishing means to which the .articles areautomatically delivered by said second conveyor and to the action of which the articles are automatically subjected after delivery thereto.

-5. In a plant for treating metal articles, the combination with a heating furnace, of an endless conveyor for transporting the articles through the furnace at such 'speed as to enable the heat treatment to be accomplished, means for automatically delivering the articles to said conveyor, pulleys over which said conveyor passes, and a cooling tank located below one of said pulleys and into which the articles may drop by gravity as the conveyor passes over said pulley.

6. In a plant for treating metal articles, the combination with a heating furnace, of a chain of conveyor buckets for transporting the articles through the furnace at such speed as to enable the heat treatment to be accomplished, means for automatically de- K means for directing livering the articles to said buckets,'pulleys over which said chain passes, and a cooling tank below one of said pulleys and into which the articles may fall by gravity as a bucket passes over said pulley.

7. In a plant for treating metal articles, the coinbination with a heating furnace, of an endless conveyor for transporting the articles through the furnace at such speed as to enable the heat treatment to be accomplished, pulleys over` which said conveyor passes, and a cooling tan-k located below one of said pulleys and into which the articles may drop by gravity as the conveyor passesv over said pulley.

8. In a plant for treating metal articles, the combination with a heating furnace, of a cooling tank for containing liquid located adjacent the rear end of the furnace, means for transporting the articles through the furnace at such speed as to enable the heat treatment to be accomplished and automatically dumping them into said cooling tank, an endless conveyor having one end located in said tank to be below the liquid level and having means for engaging the articles in the liquid to deliver the-m from the tank, and means for preventing the articles from oating on the surface of the liquid.

9. In a plant for treating metal articles, the combination with a heating furnace, of a cooling tank for containing liquid located adjacent the rear end of the furnace, means for transporting the articles through the furnace at such speed as to enable the heat treatmentto be accomplished and automatically dumping them into said cooling tank, an endless conveyor having one end located insaid tank to be below the liquid level and having means for engaging the articles in the liquid to deliver them from the tank, and jets of water against' the articles adjacent the surface of the liquid in the tank to prevent -the articles fromv floating on the surface.

10. In a plant for treating metal articles, 1n combination with a heating furnace, an endless chain of buckets for/conveying the articles through the furnace, means for driving the bucket chain at such a speed as to enable the heat treatment to be accomplished, and means for automatically delivering measured charges of the articles to the successive buckets.

11. In a plant for treating metal articles, and in combination, a heating furnace, a plurality of conveyor buckets movable therethrough, means for moving the buckets, means for automatically delivering articles to be treated to said buckets, and means dependent on the relative position of the buckets for controlling the operation of said delivery means.

12. In a plant for treating metal articles, and `in combination, a heating furnace, a plurality of conveyor buckets moving therethrough, a hopper having a gate and arranged to deliver articles to the conveyor buckets by gravity when said gate is opened, and means controlled by the relative position of the buckets for opening said gate.

13. In a plant for treating metal articles, and in combination, a heating furnace, means for conveying articles to be treated through said furnace, a hopper having a gate and arranged to deliver articles to the conveyor means automatically when the gate is opened, and means controlled by the relative position of the conveyor means for opening said gate.

14. In a plant for treating metal articles, and in combination, a heating furnace, a chain of conveyor buckets movable therethrough, pulleys over which the buckets pass, means for driving the conveyor chain, a hopper located above the point where the buckets take an upright position and having a dumping ate, whereby articles in the hopper are de ivered to the bucket by gravity when the gate is opened, and means dependent on the relative position of the buckets for causing said gate to open.

15. In a plant for treating metal articles, and in combination, a heating furnace, a chain of conveyor buckets movable therethrough, pulleys over which thebuckets pass, means for driving the conveyor chain, a hopper located above the point where the buckets take an upright position and having a dumping gate, whereby articles in the hopper are delivered to a bucket by gravity when the gate is opened, and means including an element actuated once for the passage of each bucket into upright position beneath the hopper, for causing said gate to open.

16. In a plant for treating metal articles, and in combination, a heating furnace, a plurality of conveyor buckets moving therethrough, a hopper having a gate and arranged to deliver articles to the conveyor buckets by gravity when said gate is opened, means tending to open sai-d gate, releasable` latch means for preventing operation of said opening means, and means controlled by the plurality of conveyor buckets moving therethrough, a hopper having a gate and arranged todeliver articles to the conveyor buckets by gravity when-said gate is opened, means tending to open said gate, a latch element for preventing the operation ofl said opening means, and an escapement mechanism for tripping said latch elem-ent as each bucket takes a receiving position below the hopper.

18. In a plant for treating metal articles,

Aand in combination, a heating furnace, a

plurality of conveyor buck-ets moving therethrough, a hopper having a gate and arranged to deliver articles to the conveyor bucketsby gravity when said gate is opened, means tending to open said gate, a latch element for preventing theoperation of said opening means, an escapement mechanism for tripping said latch element as each bucket takes a receiving position below the hopper, and .means by which the latch may be reset after each tripping operation.

19. In a plant for treating metal articles, and in combination, a heating furnace, a plurality of conveyor buckets moving therethrough, a hopper having a gate andarranged to deliver articles to the conveyor buc ets by gravity when said gate is opened, means tending to open said gate, a latch Ielement forpreventing the operation of said ope-ning means, a notched escapement wheel moving in unison with the buckets, a springpressed dog riding on said wheel, an operating element for tripping said latch, and a connection between said operating element and said dog. v

20. In a plant for treating metal articles, and in combination, a heating furnace, a

plurality ofv conveyor buckets moving therethrough, a hopper having a gate and arranged to deliver-articles to the conveyor buckets by gravity when said gate is opened, means tending to open said gate, a latch element'for preventing the operation of said opening means, an` operating element for tripping said latch, a notched escapement wheel movinginunison with the buckets, a spring-pressed dog riding on said wheel, and a separable connection between said dog and theoperating element whereby the latchmay be reset as soon as it has been tripped regardless of the position of the dog.

21. In aplant for treatmg metal articles,

yand in combination, a heating furnace, a

plurality of conveyor buckets moving therethrough, a hopper having a gate and arranged to deliver articles to the-bucketsv by gravity when the gate is opened, a rock shaft, a connection between the gate and the rock shaft, a weighted arm mounted on the rock shaft and arranged to be raised when the gate is closed, whereby the weight tends to swing` down and open said gate, a latch element for holding said weight raised, and,l means for tripping said latch.

22. In a plant for treating metal articles, and in combination, a heating furnace, a plunality of conveyor buckets moving therethrough, a hopper having a gate and arranged to deliver articles to the buckets by gravity when the gate is opened, a rock shaft, a connection between the gate and the rock shaft, a weighted arm mounted on the rock shaft .and arranged to be raised when the gate is closed, whereby the weight tends to swing down and open said gate, a latch element for holding said weight raised, and means controlled by the relative position of the bucket for tripping said latch.

23. Ina plant for treating metal articles, and 4in combination, a heating furnace, a plurality of conveyor buckets moving therethrough, al hopper having a pair of complementary gates .and 'arranged to deliverl articles to the conveyor by gravity when the gates are opened, a rock shaft on which one gate is mounted, arconnection between the rock shaft and the other gate for causing simultaneous gate movement, a weighted arm mounted on the rock shaft and arranged to be raised when the gates are closed, where- .said latch.

24. In a plant for treating metal articles, and in combination, a heating furnace, a plurality of conveyor buckets moving therethrough, a hopper having a gate and ,arranged to -deliverarticles to the buckets by gravity` when the gate is opened, means tending to open the gate, a latch for preventing operation of said Ao ening means, an escapement wheel moving 1n unison with the buckets, a dog Vriding on said escapement wheel, a connection between said latch for tripping the latter and including two separable blocks, a catch for causing said blocks to move as a unit, and means for tripping said catch at the end of the latch tripping stroke, whereby the latch may be reset regardless of the position of theescapement dog.

25. In a plant for treating metal articles, and in combination, a heating furnace, a plurality of conveyor buckets movable therethrough, a measuring hopper having a capacity substantially -that of' one bucket and having a gate, the hopper being Jarranged to deliver the articlesto the conveyor buckets by gravity when the gateis opened, means preventing operation of the opening means, and means controlled by the relative position of thebuckets for tripping said latch. 26; In a plant for treating metal articles,

5 and in combination, a heating furnace, a

plurality of conveyor buckets movable therethrough, a. measuring hopper having a capacity substantially that of one bucket and having a gate, the hopper being arnanged to 10 deliver the articles to the conveyor buckets by gravity when the gate is opened, means tending to openthe gate, latch means for preventing operation` of the opening means, means controlled by the relative position of the vbuckets for tripping said latch, and 15 means for delivering articles to the hopper.

In testimony whereof, I have hereunto set my hand.

DAVID L. SUMMEY. I

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