US1472529A - Furnace - Google Patents

Description

H. A.'KUNlTZ FURNACE Filed July 1, 192

3 Sheets-Sheet 1 BY M ATTORNEYS @ct 3O 1930 H. A. KUNITZ 5 Sheets-Sheet 2 INVENTOR H. A. KUNITZ FURNACE v Filed July 1. 1921 3 Sheets-Sheet 5 III I i N ENTQR 14/ Ma BY I ATTORNEYS treated, conveyin Patented Get. 30, 1923.

HANNIBAL A. KUNITZ, 0F SPRINGFIELD, MASSACHUSE'ITS, ASSIGNOR TO ADVANCE FURNACE & ENGINEERING COMPANY, OF SPRINGFIELD, MASSACHUSETTS, A COR- PORATION OF MASSACHUSETTS.

FURNACE.

Application filed July 1, 1921. Serial K0. 481,998.

To all whom it may concern Be it known that I, I-IANNIBAL A. KUNITZ, born in Tunis of a German father and a French mother and not positively knowing of what citizenship I am, but having formally declared my intention of becoming a itizen of the United States in accordance with the United States naturalization laws, and having diligently prosecuted my application for United States citizenship to date, and now residing at Springfield, in the county of Hampden and State of Massachusetts, United States of America, have invented new' and useful Improvements in Furnaces, of which the following is a specification. 1

The present invention relates to furnaces such as are used for heating various articles of manufacture preparatory to subjecting them to hardening, tempering,annealing, or other heat-treating operations. More particularly, the invention relates to furnaces of this general character which are provided withmeans for automatically introducing into the furnace the articles to be the articles through the furnace, and final y discharging them therefrom. v

Furnaces of the particular type above referred to have been constructed with an elongated heating chamber adapted to contain a series of shallow trays in which the articles to be heated are placed, the chamber havin openings at its opposite ends for the intro uction nd discharge of the trays, and a sliding doo has been provided upon the outside of the furnace for normally closin the opening at the discharge end thereo In these furnaces the tra s are advanced step-by-step through the eating chamber by means of horizontal transporter bars which are movable both longitudinally and vertically and are located in longitudinal grooves in the floor of the furnace. Between successive ste movements. of the trays a sufiicient perlod of time elapses to insure proper heating of the "articles; During' these heating periods the transporter bars are maintained in their lowermost positions, out of contact with the trays and the latter rest upon the floor of the furnace. At the expiration of each heating period, the transporter bars are raised to lift the series of trays off from the furnace floor amount of heat is lost through the opening at the discharge end of the furnace so that adjacent this end the temperature within the heating chamber is reduced to a degree which is ineffective to produce the desired results. It is very important, in order to insure proper heating .of the articles, that the foremost article or tray of the series shall not be advanced beyond the effective heating space until it is ready to be finally discharged from the furnace. In other words, a substantial distance should intervene between the foremost article of the seriesand the delivery end of the furnace during the heating period. Accordingly, it has been proposed to advance the transporter bar, at each step movement, through a total distance equal to the length of a tray plus the length of the ineffective heating space at the delivery end of the furnace plus also, a certain amount of clearance for the sliding door. In this Way, the foremost tray is moved from a position within the effective heating space to a position entirely clear 'of the furnace, as desired, and the trays successively introduced into the furnace are spaced apart by a distance equal to that part of the feed movement which is in excess of the lenth of one of the trays. A substantial distance, therefore, intervenes between each tray of the series and consequently the operating capacity of the furnace is materially reduced.

One of the objects of the present invention is to increase the effective operating capacity of furnaces of the character above indicated without correspondingly increasing the size of the furnace.

With this object in view, one important feature of the resent invention consists in the provision, 1n conjunction with a feed device for advancing a series of articles step-by-step through a furnace, of means for causing the foremost article of the series to be fed a greater distance, at each step movement, than the other articles of the series.v

In the furnace illustrated as embodying the present invention, the feed device comprises a pair of horlzontal, longitudinally movable transporter bars similar to those described" in said prior application. In the preferred embodiment of the above named feature of the invention, the floor of the present furnace is recessed beneath the portion of the main heating chamber occupied by the tray or article next to be discharged from'the furnace and provision is made whereby, after the series of articles has been advanced a distance only slightly in excess of the length of each individual article, the transporter bars are lowered a distance insufiicient to deposit the foremost aItlCle of the series upon the recessed portion of the furnace floor, but sufiicient to deposit all the other articles of the series upon the main portionof the floor and thus to arrest their further advance. Subsequently to the lowering of the transporter bars an additional longitudinal feed movement is imparted thereto continuing the advance of the foremost article until it has been completely discharged from the furnace. Another object of the invention is to provide, in a furnace having a feed device for advancing a series of articles therethrough, means for automatically supplying articles to the feed device in order that they may be introduced thereby into the furnace.

To this end, a supply magazine is located adjacent the receiving end of the furnace, the magazine being constructed and arranged to support an upright stack of articles to be heated and to permit the removal of the articles, one-by-one, from the bottom of the stack, and a feed member is provided on the transporter bar which is adapted, upon the advance of said bar, to engage the lowermost article and remove it from the magazine so that it will be deposited upon the transporter.

To provide for more thorough and uniform heating of the articles, a further feature of the invention contemplates timing and coordinating the movements of the transporter bars in such a manner as to maintain them stationary in their uppermost positions throughout what may be termed a heating period at each cycle of operations of the feed device so that during this interval of time the articles will remain elevated somewhat above the floor of the furnace thus causing the lower faces to be effectively exposed to the heat.

The invention further consists in the features of construction and combinations of parts hereinafter described and particularly pointed out in the appended claims, the advantages of which will be apparent to those skilled in the art.

The various features of the invention will be best understood from a description of the preferred embodiment thereof, illustrated in the accompanying drawings, in which I Fig. 1 is a view, in side elevation, of a furnace constructed in accordance with the present invention, a portion of the furnace wall beingbroken away and parts of the feed device shown in section to more clearly reveal its construction;

Fig. 2 is a detail sectional view, taken on the line 22 of Fig. 1;

Fig. 3 is a detail sectional view, taken on the lin 3-3 of Fig. 1;

Fig, 4 is a ems-sectional view, taken on the line 44 of Fig. 1;

Fig. 5 is a longitudinal sectional view of a rotary valve for controlling the movements of the feed mechanism and other moving parts associated with the furnace, the rotary element of the valve being shown in the radial position it occupies during the periods of inaction of the feed device;

Fig. 6 is a diagrammatic view illustrating the connections between the rotary control valve and the several cylinders;

Figs. 7, 8, 9, 10, 11, and 12 are cross sec tional views, taken, respectively on the lines 7-7. 88, 9-9, 10-10, 11-11, and 12-12 of Fig. 5;

Fig, 13 is a diagrammatic view illustrative of the means for actuating the rotary control valve; and- Fig. 14 is a series of six sectional views taken in a plane extending longitudinally through the furnace floor and illustrating diagrammatically the positions of the articles being ope-rated upon at different stages of each cycle of operations. l

The illustrated furnace is similar, in many of its structural details to furnaces heretofore constructed. In common with such prlor constructions, the present furnace comprises an elongated body portion 15', of fire-brick or other heat-resisting material, having a continuous passage 16 extending longitudinally from one end thereof to the other. The bottom and op osite sides of the furnace are enclosed am protected by means of a base plate 17 (Fig. 4) andside frames 18, respectively, the lower edges of the latter resting upon projecting marginal portions of the base plate. lihe furnace is supported above the floor by means of suitable pedestals 19 secured to the base plate 17. The left-hand portion of the passage 1(3, viewing Fig. 1, is somewhat enlarged vertically to form the main heating chamber of the furnace, while the righthand portion of the passage 16 constitutes a re-heating chamber.

he articles are advanced through the furnace by imeans of a pair of horizontal transporter bars 20 which are both longi vention and will hereinafter be described in detail.

The means for effecting the vertical movements of the transporter bars 20 is substantially the same as the corresponding means described in said prior application.

.Briefly described, the transporter bars 20 are raised and lowered by means of a vertically-movable support comprising a pair of longitudinal. bars 24 severally arranged in the lower portions of the grooves .21 underlying the transporter bars. To facilitate the longitudinal movements of the transporter bars relatively to the supporting bars 24, the latter are provided with longitudinal grooves 25, of curved cross-sectional shape,

in which rest the lower portions of balls 26, the upper portions of which project into corresponding grooves 27 in the lower faces of the transporter bars. Each of the supporting bars 24 is carried by a plurality of vertical supports 28 which extend downwardly belowthe furnace and are secured at their lower ends to a longitudinal beam 29. The two beams 29 are tied together by means of suitable transverse members 30 so as to form a single unitary lifting frame. Thev lifting frame is supported by means of four links 31, a pair of which are pivotally connected at their lower ends to each of the longitudinal bars 29 adjacent the opposite ends thereof. *The upper ends of the four links 31 are pivotally connected to the inwardly directed extremities of two pairs of arms 32, said arms being severally secured to a pair of rock-shafts 33 which are journaled in bearings on the under side of the furnace adjacent its opposite ends. At least one of the vertical supports 28 is made wide enough for the provision of a vertical guiding'slot 35 in which is received a pin 36 carried by the base plate of the furnace and by means of which the lifting frame comprising the supporting bars 24 is constrained to move in a vertical path. The vertical movements of the supporting bars 24 areeffected by simultaneously rocking the shafts 33. To this end, a pair of toggle levers 38 are provided which are severally' secured to the rock-shafts 33 at one side of the furnace and extend toward achother. The opposed'endsof the toggle-levers 38 are connected by means of links 39 with the lower end of a piston rod 40, the latter being provided with a piston 40 which is movable within a cylinder 41 and to be exhausted from said end to lift the piston and tho pistonirod 40 and thus to raise the supporting bars 24 or to lower said piston rod and said supporting bars. The construction and modeof operation ofthe parts thus far described is substantially the same as that of corresponding parts of furnaces heretofore generally used for the purposes set forth.

The present furnace is adapted for use in heating articles of various forms and sizes. Small articles may. be placed in shallow trays and the trays introduced into the receiving end of the furnace. If the articles are generally flat, however, and large enough to bridge across the grooves 21 in the floor of the furnace, the trays may be dispensed with and the articles may be directly engaged and moved by the transporter bars. In the drawings, the furnace is illustrated as acting upon annular gears, a supply of the gears being contained in a magazine 43 from which they are automatically delivered directly to the transporter bars, as Will be hereinafter described.

In furnaces commonly used heretofore, the articles being heated are caused to'remain stationary between successive feed movementsof the transporter bars 20 for sufficient periods of time to insure the proper heating of the articles, the length of these periodswarying with the character of the articles. At the expiration of each heating period in said furnace, the articles are raised to clear the floor of the furnace,

advanced'through a step movement and then deposited on the floor preparatory to the occurrence of the next heating period while the transporter barsare. returned in readiness for the next feed movement. \Vith this mode of operation, as heretofore pointed out, the transporter bars are necessarily advanced a distance considerably in excess of the length of the articles or trays of the series in order to provide for the required clearance to allow for the presence of an ineffective heating space at the discharge end of the furnace. As a result of this excess feed movement the articles or trays must, in said furnace, be spaced apart a distance equal to the extent of the excess feed, and thus the capacity of the furnace is reduced.

In accordance with the present invention, however, provision is made for causing the foremost articles of the series to be advanced through a greater distance, at each step movement, than the other articles of the series, or, in other words, causing the neccausing a similar amount of excess movement to be imparted to the other articles of the series. Thus, the necessity of having all the articles of the series spaced apart by a distance equal to the extent of the excess feed movements is obviated. To accomplish this result, the floor of the furnace is recessed adjacent the discharge end of the furnace, as indicated at 44 in Fig. l, to a horizontal plane below that occupied by the upper edge of the transporter bars when the latter are in their lowermost positions and, at each cycle of operations, the transporter bars are given an initial feed movement equal only to the length of the individual articles to be heated, after which the transporter bars are lowered to such an extent that while the foremost article of the series remains resting upon said bars, all the other articles of the series will have been deposited upon the floor of the furnace thereafter, at the same cycle of operations the transporter bars are given an additional forward feed movement, which is suffirient to discharge the foremost article through the opening at the discharge end of the furnace. This additional advance movement of the transporter bars is imparted to the foremost article since this article is still supported entirely by the bars, but said movement is ineffective to further advance any of the other articles of the series, since the transporter bars are not in cont-act therewith.

Furthermore, in accordance with the present invention, the series of articles within the furnace are raised above the floor of the furnace and advanced one step therethrough, prior to the beginning of each heating period, this forward step movement advancing the foremost article of the series to a point which is within the effective heating space at the discharge end of the furnace. The articles are maintained in their elevated positions, slightly above the furnace floor, throughout the duration of each heating period. Thus, the greater part of the lower sides of the articles are exposed to the heat of the furnace and consequently a more thorough and uniform application of heat is obtained. At the expiration of each heating period the first movement of the articles in the present furnace is a downward movement caused by the lowering of the transporter bars, which, for the convenience of description, will hereinafter be considered the first stage in the cycle of operations of the mechanism.

The means for moving the transporter bars longitudinally, comprises a pair of cylinders 45 and 46 (Fig. 1) which are horizontally disposed and arranged in axial alinement beneath the furnace. The initial movement of the transporter bars which is effective to produce a step movement of the series of articles within the furnace is derived from a piston 46 (Fig. 6) within the cylinder 46, while the additional feed movement of the transporter bars for the purpose of discharging the foremost article of the series from the furnace is derived from a piston 45 (Fig. 6) within the cylinder 45. To effect the above results the cylinder 46 is rigidly secured to the floor and its piston is provided with a rod 47, while the cylinder 45 is mounted to slide bodily back and forth in longitudinal directions and is connected directly to the outer end of the piston rod 47 so as to be reciprocated thereby. The piston of the cylinder 45, in turn, is provided with a piston IOdf48, the outer end of which is connected by the means of a link 49 with the lower end of bracket 50, the latter depending from the outwardly projecting ends of the transporter bars 20 and serving also to rigidly connect said bars so that they will move in unison. To permit sliding movements of the cylinder 45, the latter is maintained upon a carriage 52 (Fig. having lateral projecting tongues' or flanges 53 adapted to slide in guideways 54 formed in a base plate 55 which is rigidly secured to the floor. As shown, the guideways 54 may be conveniently formed by recessing the upper face of the base plate 55 to receive the carriage 52 and securing a pair of gibs 56 to the base plate in such a way as to overlap the flange 53 of the carriage, and thus to prevent upward displacement of the latter. To actuate the pistons to the cylinders 45 and 46 each of these cylinders is adapted to be supplied with fluid under pressure and to be connected to exhaust said fluid by means hereinafter to be described. When the fluid under pressure is admitted to the cylinder 46 to effect the initial feed movement of the transporter bars, suitable pressure conditions will be maintained in cylinder 45 to cause the iston of the latter cylinder to move therewith. The additional feed movement of the transporter bars for the purpose of discharging from the furnace the foremost article of the series, is subsequently effected by the movement of the piston within the cylinder 45 and relatively thereto.

Inasmuch as the opening at the dischar e end of the furnace opens directly into tEe main heating 0 linder, provision is made for closing thls opening except during the passage therethrough of the articles. The opening at the receiving end of the furnace being remote from the main heating chamber, a closure therefor is unnecessary and, as shown, none has been provided. The means for enclosing the opening at the discharge end of the furnace comprises a vertically-sliding door 58 which is normally maintained in closed position, as illustrated in Fig. 1, but is automatically movable to open position just prior to the imparting of the additional feed movement to the transporter bars for the purpose of discharging an article from the furnace.

To this end, the door 58 is mounted in suitable guideways at the discharge end of the furnace and is suspended by means of a cable 59, the upper end of which is fixed to a curved segment 60 pivotally supported by a bracket 61 secured to the top of the furnace. The segment 60 is movable by means of an arm 62 projecting therefrom, the outer end of which is connected by a link 63 with one of the toggle-levers 38 at ezvpoint intermediate the ends of the latter.

1th this arrangement, when the toggle-levers 88 are swung downwardly at the beginning of each cycle of operations to lower the transporter bars, the door 58 will be raised to open position. This occurs just prior to the additional feed movement of the transporter bars, which carries the foremost article of the series through the d scharge opening. Whenthe toggle-levers 38 are subsequently swung upwardly to raise the transporter bars, preparatory to the next feed movement thereof, the door, will be lowered into closed position.

After passing through the discharge opening, the articles may be removed in any desired way. As shown, a table 65 is providcd for receiving the discharged articles.

This table 65 is adapted to be tilted after anart'icle has been deposited thereon to cause the article to slide off from the table. Upon leaving th table 65, the article may fall into a suitable receptacle, which,i f desired, may constitute a quenching tank, 'or the article may be delivered to a suitable conveyer by means of which it Will be transferred to de vices for performing operations thereon. To this end, the table 65 is pivoted at 66 to brackets 67,..which are secured to the delivery end of the furnace. table 65 or to the pivot 66 is an arm 68, the lower end of which is connected by a link 69 to one arm of a rocker member 70 which is mounted to oscillate upon the rock-shaft 33 at the adjacent end of the, furnace. The rocker member 70 is provided with a second arm 71, the lower end of which is connected by a link 72 with a piston rod 73 carrying a piston 74f movable within a. vertical cylinder 74, the latter being rigidly secured to the side frame '18 at one side of the furnace. The magazine 43 which contains a supply of the articles to be heated is located immediately above the transporter bars at the receiving end of the furnace and is rigidly supported by a bracket 75 secured to the end wall of the furnace. As shown in Figs. 1 and 2, the magazine comprises a tube-like shell. vertically disposed and having a pair of inwardly-projecting lugs 76 at its lower end for supporting a stack of annular or Fixed to the disk-shaped articles. ,The cylindrical side wall of the magazine is adapted to fit closely the circular outline of the articles contained in the magazine to maintain said articles with their edges vertically alined. The side wall of the magazine is cut away, adjacent its lower ,edge, to provide an opening 77 of such size as to ermit the removal, in the direction of fee of a single articleat a time from the magazine. The side wall of the magazine is also cut away from. the. top to bottom, as indicated at 78, (Fig. 2), to facilitate the loading of the article therein.

The articles are successivel removed from the magazine 43 by means 0 feed members 79, one of which rises from each of the transporter bars 20 and is so located on the bar as to lie beneath the opening in the annulai articles when the bars'. are in their fully retracted positions, as indicated in Fig. 1. Upon a subsequent rise of the transporter bars, the feed members 79 are raised into position to engage the inner edge of the lowermost annular member in the magazine, and when the transporter bars are advanced to impart the next feed movement to the series of articles in the furnace, the feed members 79 will feed the articles engaged thereby through the o ening 77. When the article which is being ed from the magazine is clear of the supporting lugs 76, it will drop upon the upper faces of the transporter bars and subsequently be advanced by said bars with the other articles of the series. At the expiration of the next heating period, the downward movement of the transporter bars retracts the feed members'7 9 from the plane of the article last engaged by the feed members 79, thereby permittin the transporter bars to be subse uent y retracted without causing 'retrogra e movement of said article.

The means for controlling the admission to the several cylinders 41, 45, 46 and 74 of compressed air or other fluid under pressure, and for controlling the ex haustof the fluid from these cylinders com-- prises a rotary valve 80 (Figs. 5 and 7 to 11 inclusive). As shown, the rotary valve-80 comprises a substantially cylindrical casing 81 and a rotor 82 which fits closely within the casing 81. The rotary valve 80 may be secured to any convenient part of the furnace, or may be located at any desired place adjacent the furnace. One end of the valve casing 81 is connected by a pressure supply pipe 83 with a suitable source of compressed air, the pipe 83 conducting the air to an inlet chamber 84. at one end of the valve casing. Within the valve casing 81, at the opposite end of the Valve 80, an exhaust chamber 85 is provided and an exhaust .pipe 86 may be connected therewith, if desired, to conduct awav the exhaust fluid. An annular shoulder ,87

is formed at the exhaust end of the valve casing to receive the thrust of the rotor 82 caused by the admission of air to the, pressure inlet end of the valve. A suitable thrust bearing 88 may be interposed between the shoulder 87 and the adjacent end of the rotor. Projecting axially at the exhaust end of the valve is a shaft 89 which extends through a stufling-box 90 carried by the valve casing and has secured to its outer end a ratchet wheel 91 for actuating the valve.

The compressed air or other fluid under pressure for actuating the pistons of the several cylinders enters the rotor 82 through a pair of parallel longitudinal passages 93 which are arranged in the same axial plane, the passages communicating at one end with the inlet chamber 84 and being closed at their opposite ends. Each of the longitudinal pressure passages 93 is provided, at regular intervals throughout its length, with one or more branch passages 94, the latter being arranged in planes normal to the length of the passage 93. The branch passages 94 are adapted to be moved by the rotation of the rotor 82 progressively into registry with a series of ports in the valve casing, the latter being connected by suitable conduits 95, 96, 97, 98, 99 and 100 with the several cylinders.

The rotor 82 is also provided with two parallel longitudinal passages 101 which are arranged in an axial plane perpendicular to the plane of the pressure passages 93. The passages 101 severally communicate with the exhaust chamber 85 at one end of the valve and are closed at the opposite end of the valve. The exhaust passages 101 are provided wit-h a plurality of branch pass- .ages 102, oneor more of which are arranged in each of the vertical planes occupied by the branch pressure passages 94.

The manner in which the conduits 95 to 100, inclusive, areconnected with the several cylinders is illustrated diagrammatically in Fi 6. As therein shown, the conduits 95 an 96 are connected with the front and rear ends, respectively, of the cylinder 45 and the valve 80 is actuated to connect one of said conduits with the pressure chamber 84 and the other with the exhaust chamber 85 for the purpose of causing the piston to move in one direction. and to reverse said conditions for the purpose of causing the piston to move in the opposite direction. The conduits 97 and 98 are connected with the front and rear ends, respectively, of the cylinder 46, and the valve 80 is actuated to effect the reciprocation of the piston within said cylinder in a manner similar to that just described in connection with the cylinder 45. The conduits 99 and 100 are connected with the upper ends of the cylinders 41 and 74, respectively. The lower ends of the cylinders 41 and 74 are connected by means of conduits 103 and 104, respectively, with the pressure supply pipe 83. With this arrangement, the lower faces of the pistons within the cylinders 41 and 74 are subjected to (onstant pressure tending to raise the pistons. \Vhen, however, the valve 80 is actuated to effect the supply of pressure through the conduits 99 and 100 to the upper ends of said cylinders, the pressure above the pistons in said cylinders will overbalance' the pressure applied beneath the pistons since the areas on the lower sides of said pistons which are subjected to pressure are less than the areas on the upper sides thereof by an amount equal to the diameter of the piston rod.

Each cycle of operations of the mechanism may be convenientlydivided into six distinct steps or stages, as follows: First, the transporter bars are lowered to deposit all but the foremost article of the series upon the floor of the furnace second, the transporter bars are advanced to discharge the foremost article from the furnace and deposited upon the tilting table third, the table 65 is tilted to deliver the article supported thereby to a suitable receptacle; fourth, the transporter bars are retracted preparatory to imparting a feed movement to the series of articles; fifth. the transporter bars are raised to lift the series of articles above the furnace floor; and sixth, the bars are advanced to impart a feed movement to all the articles within the furnace. Accordingly, the rotor of the valve 80 is adapted to be rotated step-by-step through the six radial positions, sixty degrees apart, to connect the various cylinders with pressure or with exhaust according to the movements which are to be given to the different parts of the mechanism. In Figs. 7 to 12 inclusive, the rotor of the rotary control valve 80 is shown in the radial position which it occupies after the sixth step of the ratchet wheel, or in other words. during one of the heating periods. During this period, thentic-les within the furnace are supported upon the transporter bars, just clear of the furnace floor as illustrated diagrammatically at F in Fig. 14.

The means for rotating the rotor of the valve 80 is illustrated diagrammatically in Fig. 13. The ratchet wheel 91 which, as before described, is secured to the rotor shaft 89, is actuated by a feed pawl 108 carried by an arm 109 which is arranged adjacent one side ofthe ,ratchet wheel and is adapted to oscillate upon the shaft 89. The pawl carrying arm 109 is os=illated to effect the step by-step rotation of the ratchet wheel 91 by means of a solenoid 110, the core of which is connected at 111 with an outer end of said arm. Any suitable commercial form 1 of timing device 112 may be employed to control the movements of the ratchet wheel by energizing or deenergizing the solenoid at proper times.

During each cycle of operations of the mechanism, the timing device 112 functions to successively initiate the six steps or stages thereof. To effect the movements of each stage of the cycle, the solenoid 110 is energized by the timing device 112 to actuate feed pawl 108 to rotate the ratchet wheel 91 through one sixth of a revolution and thereby to impart a step movement of one sixth of a turn to the rotor of the valve 80. Between successive cycles, or throughout the duration of the heating periods, the various mechanisms of the furnace are inactive and the rotor of the valve 80 is positioned radially as shown in Figs. 7 to 12 inclusive.

To produce the desired movements constituting the first stage of a cycle, the rotor of the valve 80 is turned sixty degrees in a clockwise direction, after the valve rotor has been thus turned, pressure will be ap-' plied through the conduit 100 to the upper end of the cylinder 41, to overbalance the constant pressure beneath said piston, thus causing the piston to move downwardly.

This downward movement of the piston ef fects the lowering of the transporter bars. As the transporter bars are lowered, all the articles of the series withln the furnace except the foremost article, are deposited upon the furnace floor in the positions shown at A in Fig. 14. The foremost article, however, being directed above the recess 44 in the furnace floor, to be supported by the transporter bars after the latter have been lowered. As the transporter bars are lowered, the door 58 at the discharge end of the furnace is raised through its connections with one of the toggle levers 38. During this first stage of the cycle, the trans orter bars are maintained in the longitudinal position to which they were advanced by the initial feed movement imparted thereto. To this end pressure is maintained in the conduits 96 and 97. I 1

The second stage of the cycle is illustrat-' ed at B in Fig. 14, and is initiated by a further rotation, in the same direction, of the valve rotor. During this second stage, a horizontal feed movement is imparted to the transporter bars for the purpose of discharging the foremost article and depositing it upon the tilting table'65. \To effect this movement, pressure is supplied through the conduit 95 to the front end of the cylinder 45 while the. rear end of said cylinthe third stage of the cycle. During this Stage, the table is tilted upwardly, as illustrated at C in Fig. 13, to cause the article supported thereby to be delivered to a suitable receptacle or conveyer. This is effected by supplying pressure to the upper end of the cylinder 74, through the conduit 99 to overbalance the constant presa sure in the lower portion of this cylinder.

During the fourth stage of the cycle which is initiated by the fourth step movement of the valve rotor 82, the transporter bars are retracted to their extreme forward positions as shown at D in Fig. 14. This result is effected through the combined ac-.

tions of the cylinders 45 and 46. To accomplish this result, pressure is supplied,

through the conduits 96 and 98 to the rear ends of the cylinders 45 and 46, while the forward ends of said cylinders are connected to permit exhaust therefrom. During this stage of the cycle, the cylinder 74 is connected with the exhaust chamber through the conduit 99, thus allowing its piston to be raised by the constant pressure beneath it.

The fifth turn of the valve rotor 82 initiates the fifth stage of the cycle, during toggle levers 38 are moved upwardly and the door 58 is closed to prevent the escape of heat from the furnace preparatory to the start of the next heating period.

The sixth step movement of the valve ro tor 82 initiates the sixth and last stage of the cycle which is illustrated at F in Fig. 14. uring this stage, the transporter bars are advanced through the first part of their horizontal feed movement to advance the entire series of articles one step through the furnace. To effect this movement the rotor of the valve'80 is again turned sixty degrees, connecting the front end of thecylinder 46 with pressure through the conduit 97 and permitting the fluid at the opposite side ofthe piston of said cylinder to exhaust through the conduit 98. The timing device 112 then causes the solenoid to remain deenergized throughout a sufiicient length of time to constitute a heating period, during which time the rotor of the valve is maintained stationary to preserve the same conditions of pressure and exhaust as prevailed at the start of the last stage of the cycle. Thus the transporter bars are maintained in their elevated positions throughout the heating period and in foremost article of the, series.

the longitudinal positions to which they were moved by the action of the piston in substantiallv equal to their length, and an additional f eed movement of the transporter bars is relied upon to effect the dischargeof the foremost article without imparting any further movement to the other articles in the furnace; Consequently in the resent furnace, the articles may be fed theret rough in close relationship so that the capacity of the furnace is greatly increased.

-VVhile it is preferred to employ the specific construction and arrangement of parts shown and described it is to be under-- stood that such construction and arrangemcnt is not essential except so far as defined in the claims and may be changed or modi fied without departing from the spirit and true scope of the invention.

What is claimed as new is:

1. In a furnace, means for feeding a series of articles step-by-step therethrough, and means cooperating-therewithfor causing the articles to be advanced through an increasee distance at the last feed movement imparted thereto but in the same direction as said stephy-step movement.

2. In a furnace of the type having an elongated chamber through which a series of separated articles are assed while being heated, means; for feeding the series of articles step-by-step through said chamber to successively advance the foremost article to the delivery end thereof, and means cooperating therewith for effecting a further advance of said foremost article to discharge it from the chamber. I

3. In a furnace of the type having a elongated chamber through which a series of separated articles are passed while being heated, the combination of a feed device for moving a series of articles step-by-step through said chamber to successively advance the leading article to the delivery end of the chamber, and means for varying the relative positions of said feed device and certain of said articles to enable the feed device to advance the foremost article of the series throu h a greater distance than the others at eac periodic operation thereof.

4. In a furnace of the type having an elongated chamber through which a series of separated articles are passed while being heated, a feed'device for moving a series of articles step-by-step through said chamber to successively advance the foremost article to the deliver end thereof, means for imparting an additional feed movement to said feed device after each of said step movements to further advance said foremost article, and means for preventing said ad ditional movement of the feed device from advancing the other articles of the series.

5. In a furnace adapted to permit the passage therethrough of a series of articles while being heated, a feed member for advancing the articles of the series step-by step to successively bring the leading article of the series to one endof the furnace,

means for actuating said feed member, auxiliary mechanism for continuing the operation of said actuating means between said step movements of. the articles to effect article of the series to said delivery opening,

and means for rendering said feed device ineffective except as to the foremost article of the series during a portion of each periodic movement of said device.

7. In an elongated furnace adapted to permit the passage therethrough of a series of articles while being heated, a floor constructed and arranged to support an article at the delivery end of the furnace at a lower elevation than the other articles of the series, a feed device for periodically raising all of the articles of the series above the furnace floor, advancing them one step to bring the leadin article to the delivery end of the furnace, t ereafter depositing all but the foremost of said articles upon the floor and continuing the advance of said foremost article to discharge it from the furnace.

8. In a furnace adaptedto permit the passage therethrough of a series of articles while being heated, a floor constructed and arranged to support a series of articles extending through the furnace with the foremost article at a lower elevation than the others, the floor having alongitudinal groove extending therein, a periodically-operable feed bar in said groove normally positioned to support all of the articles of the series above the floor of the furnace, means for actuating the feed bar to impart step movements to the series of articles to successively advance the foremost article to the delivery end of the furnace, means operative between said step movements for lowering the feed bar to deposit all of the articles of the series except the foremost upon the floor of the furnace and for further actuating the feed bar to impart an additional movement to said foremost article.

9. In a furnace, a longitudinally-movable transporter normally maintained stationary in its uppermost position to support a series of articles above the floor of the furnace, and periodically-operated means for advancing the transporter to impart a step movement to the series of articles supported thereon, lowering the transporter to deposit said articles upon the floor of the furnace, retracting the transporter, and raising it to its normal supporting position.

10. In a furnace, the combination of a magazine for containing a supply of articles to be heated, a feed device for advancing the articles through the furnace, and upon which the articles are supported while being advanced, and means carried by said feed device for automatically transferring articles from the magazine to the feed device.

11. In a furnace, the combination with a feed device for advancing through the furnace in separated relation a series of articles to be heated. of a magazine containing a supply of said articles and means for transferring the articles singly from the magazine to the feed device.

'12. In a furnace, means for feeding a series of separated articles step-by-step therethiough and for introducing a new article into the furnace at each step movement of the series, and means for causing the articles to be advanced through an increased distance at the last feed movement imparted thereto.

13. In a furnace adapted to permit the passage therethrough of a series of articles to be heated, conveyer means for advancing the articles step-by-step through the fur nace in a horizontal direction, said means advancing the foremost article of the series farther in the same direction than the others, and means for periodically supplying new articles to said conveyer means.

14. In a furnace, the combination with an intermittently-actuated feed device for advancing through the furnace in separated relation a series of articles to be\heated, of a magazine adjacent the feed device for holding a supply of said articles, and means on the feed device for removing an article from the magazine and transferring it to the feed device at each actuation of the latter.

15. In a furnace, the combination with aperiodically-actuated transporter for feeding a series of separated articles step-bystep through the furnace, of a magazine constructed and arranged'to hold the supply of said articles in upright stack formation above the transporter and to permit the removal of the articles singly from the magazine in the direction of feed, and afeed member on the transporter for engaging the lowermost article in the stack at each periodic operation of the transporter and transferring said article to the transporter.

16. In -a furnace adapted to. permit the passage therethrough of a series of articles while being heated, the combination with a supply magazine adjacent one end of the furnace for holding a vertical stack of articles, the magazine being constructed and arranged to permit the removal in the direction of feed of the lowermost article therein, of a feed bar longitudinally reciprocable for advancing the series of articles step-by-step through the furnace, a feed member rising from the feed bar, means for raising the feed bar prior to its advancing movement to position said feed member in the plane of the lowermost article in the stack and for lowering the feed bar after it has been ad.- vanced to permit said feed member to return beneath the magazine.

17. In a furnace adapted to permit the passage therethrough of a series of articles while being heated, a longitudinally-mot able transporter, means for actuating the transporter to advance the series of articles step-by-step through the furnace, a magazine for containing a supply of articles to be operated upon, means on the transporter for removing the lowermost article from the magazine and advancing it into the furnace, and means operative after the transporter has advanced through a portion only of its movement to renderthe continued advance of said transporter ineffective to further feed any of the articles of the series except the foremost.

18. In a furnace having openings at its opposite ends for the introduction and discharge of articles, a door for closing the opening at the discharge end of thefurnace, periodically-operable means for advancing a series of articles step-by-step through the furnace to successively bring the leading article to the discharge end of the furnace, means cooperating with said feed means between said step movements for imparting an additional feed movement to the former to discharge the foremost article from the furmice, and means for opening the door to permit such discharge and thereafter closin' the door and for rendering said additionafeed movement ineffective to advance the other articles of the series.

19. In a furnace having openings at its opposite ends for the introduction and dis charge of articles, a door for closing the opening at the discharge end of the furnace means for feeding a series of articles stepby=step through the furnece to successively advance an article to the discharge end of the furnace and for continuing the advance of said article to discharge it from the furnace, means for raising the articles prior to each advance of the series and for lowering the series of articles prior to each additional movemeni of the foremost article thereof, and means for opening the door during the lowering of said series or" articles and for closing the door during" the raising of said emiclw.

20, In e ijurnece adapted to permit; the passage iherethrough of articles to be hee ed, a floor upon which the articles may be supported, a longi-eudinel groove in said emme floor, av horizontal transporter bar movable vertically and longitudinally in said groove, e supply magazine adjacent one end of the furnace for holding a, supply of said articles, means periodically operative 0 import successive downward, backward, upward, and forward movements to the transporter bar to advance articles step-by-sceg through the furnace, and an upward projection at the rear of the transporter bar for entering the magazine to remove a single er'isicle therefrom and to advance said article tovverd the furnace at each cycle of operations of the transporter her.

HANNEBAL A, KUNETZ.,

Images