US1819509A

US1819509A - Counterflow carburizing machine

Info

Publication number: US1819509A
Application number: US347421A
Authority: US
Inventors: Henry H Harris
Original assignee: Individual
Current assignee: Individual
Priority date: 1929-03-15
Filing date: 1929-03-15
Publication date: 1931-08-18
Anticipated expiration: 1948-08-18

Description

Aug. 18, 1931. HARRls 1,819,509

COUNTERFLOW CARBURIZING MACHINE Filed March 15, 1929 2 Sheets-Sheet 1 Aug. 18, 1931. H. H. HARRIS 1,819,509

COUNTERFLOW CARBURI Z ING MACHINE Filed March 15, 1929 2 Sheets-Sheet 2 Patented Aug, 18, 1931 STATES HENRY H. HARRIS, OF DETROIT, MICHIGAN COUNTERFI-OW CARBURIZING MACHINE Application filed March 15, 1929. Serial No. 347,421.

I This invention relates to heat treating furnaces and has for its object to provide a furnace wherein heat treating or carburizing boxes may be transported therethrough in.

such manner as to heat the boxes and contents in an even and progressive manner whereby the contents may be subjected to temperatures in direct accord with the tem perature of the furnace and the time of exposure to the interior thereof.

Specifically, one of the main features of the invention resides in the revision of conveying means interiorly o the furnace of such construction as to maintain the heat treating boxes in suspended relation in order that they may be subjected to the heat of the convection and substantially free from any heat of radiation.

Heretofore, conveyor chains or an endless succession of connected links have usually been employedas the conveyor, the article containing boxes being supported thereon for transportation through a furnace. It is seen that the radiated heat from the conveyor links to the boxes may be and actually is transferred or radiated to the boxes at an entirely different rate than is the heat of the surroundin air transferred to the boxes .by convection. T e result is that the articles w within the box do not receive heat in an even and progressive manner from all sides of the .boxes but are subjected to heat through the walls and top at one rate of absorption while an entirely difl'erent rate is set up through 85 the bottom of the boxes. Of course, this rate has been computed and allowed for by vary ing the thickness of the walls of the boxes with respect to the bottom, but it is obvious that such corrective measures add com lications which do not lend themselves readily to mathematical solution and altogether cannot be termed satisfactory for many articles. It is a "further object to provide alternate means for conveying boxes through my furnace without regard to their position with respect to each other so that a box, if desired, may be carried through the furnace alone, and also to provide an arrangement employing the suspended principle which is dem pendent on the furnace being filled to capacity less one box in .order to permit of travel therethrough. In other words, it is possible under the teachings of theap lication to provide actuating means for the oxes individually or to construct a mass arrangement wherein a limited number of boxes receive actuation and push other boxes in alignment therewith by an abutting relation.

A still further and important feature of this invention resides in the provision of a furnace of the type described wherein the sus pended boxes or containers are inserted into one end thereof, are caused to travel through the length of the furnace and return to the entering end at a different strata or elevation for removal. Specifically, this object depends primarily on the use of two conveyors having an elevator for transferring the boxes individually from one to the other of the conveyors and in placing them on a lower flight in such manner that their transportation continues in reverse direction, and also in adapting both types of conveyors described to this two flight arrangement.

Other flights might beadded' or merely a siigle flight might be used, if desired.

ther objects of the invention either directly described or indirectly implied will be evident to'one skilled in the art as reference is had to the accompanying drawings wherein is illustrated one embodiment of my invention. by way of example only, and not in a limiting sense, and in which Figure 1 is a side elevation of an improved type of furnace embodying my novel conveying means, partially in section for illustrative purposes;

Figure2 is a transverse section taken along P the line 2 X of Figural;

Figure 3 is a detail view ofone roller, of

the conveyor and a track portion for cooperation therewith as attached to a box;

Figure 4 is a modification of the detail showing of Figure 3;

Figure 5 is a further modification of the detail showing of Figures 2 and 3; and

Figure 6 is a vertical section taken longitudinally through a furnace illustrating an alternate type of conveyor.

Referring more particularly to the drawings, numeral 1 refersgenerally to a heat treating furnace designed for a two flight conveyor and having a door 2 for the entrance and a door 3 for the exit, which doors may be opened by any desired arrangement such as chains 4 and pulleys 5.

Extending through the side walls of the furnace are a plurality of shafts 6 the axes of which all lie in substantially the same plane, a slight tilt being imparted to the angle of this plane if desired to assist the movement of the boxes thereover by gravity if desired. A second row of shafts? extends through the opposite walls and lie in a plane well below that of the shafts '6. Each of these shafts 6 and 7 projects both inwardly and outwardly of the furnace walls resting in suitable bearings 8 and supporting rollers 9 interiorly of the furnace and gear wheels 10 outwardly of the furnace. The rollers are all of equal size and it will be seen that four rows of rollers are provided, the rowsbeing oppositely disposed in pairs while one row is well above the other to provide a.two flight conveyor, the flights of which may be separated by a floor 11 extending throughout the major portion of the length of the furnace in order to direct a flow of heat in such manner that it can best be utilized or taken advantage of to furnish heat to the space adjoining the rollers in a progressive manner.

Article containing receptacles 12 are fashioned in such manner that rims 13 protrude from each and to each of these rims are attached tracks 14; The rims may be formed in a variety of ways depending largely on the particular type boxemployed, as indicated at 13 and 13 in Figures 3 and 5 respectively, it being merely necessary to form the rims in such way that a firm and reliable sup ort for the boxes be provided. The trac s which form an integral part of the boxes may likewise assume numerous'shapes as indicated at 14, 14' and 14" of Figure 3, 4 and 5 accordin to their size and the nature of their duties, it being a salient point that the tracks be given such width as will permit always of a good surface for contact with the rollers irrespective of expansion, contraction or warping and it is also recommended that these tracks be attached to the

rims

13, 13' and 13" with a sliding connection 15 to prevent breakage upon differential expansion of these members. The boxes are given a width in accordance with the width of the furnace so that when they are inserted into the entrance past the door 2, the tracks 14 will ride the rollers 9. The bottoms of the boxes are well above the floor 11 throughout their travel over the upper flight of their travel and a similar s acing is provided for the bottom flight so that the boxes are suspended throughout the time they travel through the furnace.

It was stated that the floor 11 extends throughout the major portion of the length of the furnace. This floor stops'short of the whole length by an amount, preferably just a bit greater than the length of the receptacles or boxes used so that the boxes may be lowered at the rear of the furnace to the lower conveyor. In order to accomplish this lowering, I provide a means which will now be described.

A platform having rollers 18 is attached to the plunger of an desired type of elevating mechanism 19 w ich might be a hydraulic jack and is given a range such that when in an elevated or extended position it will form a table upon which the bottom of one box at a time may roll as its track 14 leaves the last roller 9 of the upper flight. The box is then lowered to a position as shown in Figure 1 where the track 14 again rests upon the rollers of the lower flight where it can resume its travel through the furnace in a reverse direction.

Of course, it is possible to provide a stationary track in place of the rollers and attach the rollers to the boxes withinthe teachings of this application, however, I have illustrated the preferred arrangement and employ the rollers held in the walls because furnace and carry gears 10, shafts 16 extend longitudinally of the sidewalls, either on one or both sides of thefurnace, carrying worm gears 17 for driving a part or all of the shafts 6. These shafts 16 are driven by any suitable means as by gears 17 and electric motors 20 and 20', the motor 20 being geared to the upper shaft 16 while motor 20' is geared to the lower shaft 17.

The operation of the motors and hence the rollers 9 are controlled by the elevator 19, the switch 21 being moved to contact a terminal 22 by the elevator when in an extended position so that a box will be propelled onto the platform and rollers 16 after which the boxes of the upper flight become stationary while the box on the platform is being lowered to the lower flight whereupon the switch lever 21 contacts the terminal 23 which starts the motor 20 and rotates the lower flight of the rollers 9 whereupon the box is carried oil the platform and forwardly of the furnace.

By this arrangement a single box may be taken through the furnace or boxes may be loaded at will.

According to the modification shown in Figure 6, the roller shafts do not necessarily extend through the walls of the furnace as there is no direct driving means therefor. These rollers 9' are merely rotatably stationed in the walls in planes as described with reference to Figure 1. Plungers 24, 25 are provided to replace the longitudinal drive shafts'and electric motors. These plungers may be pneumatically or hydraulically operated. The plunger 24 is mounted at the front end of theupper flight so that as a box is placed upon the lower flight of rollers a piston pushes it toward the rear of the furnace. As a second box is placed on the rollers, a push thereon by the pistoin 26 will propel both boxes until one box shall have attained a positiomfor propulsion upon the elevator platform and rollers 16' which is similar to that described in connection with Figure 1. Of course, I contemplate the use of a safety device, if desired, to prevent ac tuation of the piston 26 unless the platform is in position to properly receive the box. As

soon as the box is lowered to a position where it rests on the lower rollers 9' a second piston-27 may drive the box or; line of boxes forward toward the lower door.

It will be noted that the upper plunger 24 i is pivotally mounted and counterbalanced by a weight 28 so that it may be swung out of position for loading of the boxes.

It will be obvious that many modifications of my invention will readily suggest themselves to one skilled in the art and; I, therefore, desire to be limited in, the application and construction thereof only by the scope of the appended claims, wherein:

What I claim is:

1. In combination with a heat treating furnace, conveying means disposed in spaced relation above the furnace floor and providing a double support at opposite sides of the furnace, and a carburizing box having means projecting outwardly therefrom above the center of gravity thereof and adapted to engage said conveying means for individually supporting the box for movement through the furnace while maintained in suspended relation above the floor, whereby to subject the box to heating substantially by convection only.

2. In combination with a heat treating furnace., a conveyor comprising double supports in spaced relation above the furnace floor along. opposite walls of the furnace, and a box having an extension thereon contiguous to the upper end thereof, and shoe portions flexibly connected to said extension and engaging said supports for movement of the box through'the furnace while maintained in suspended relation above the floor.

3'.-, In combination with a heat treating furnace, article containing boxes, flanges integral with said boxes and extending outwardly therefrom at points above the center of gravity thereof, and a movable conveyor supported in oppositely disposed walls of said furnace for supporting the boxes individually through the flanges of said boxes whereby the boxes may be transported through said furnace in suspended relation.

4. In combination with aheat treating furnace, article containing boxes, flanges integral with said boxesand extending outwardly therefrom contiguous to the upper portion thereof, and a movable conveyor supported in oppositely disposed walls of said furnace at a fixed elevation above the.

floor for supporting the boxes individually through the flanges of said boxes whereby the boxes may be transported through said furnace in suspended relation, said conveyor comprislng a plurality of spaced rollers rotatably mounted on shafts supported individually in the walls of said furnace,

5. In combination with a heat treating furnace, article containing boxes, rims on said boxes supporting fiat track sections in spaced relation with the walls of said boxes and a movable conveyor supported in oppositely disposed walls of said furnace for engagement with said track sections whereby saidboxes may, be transported through said furnace in suspended relation.

6. In combination with a heat treating v,

furnace, article containing boxes, rimson of, track sections of substantial width attached to said projecting portionin spaced relation to the box walls and adapted to engage said conveyor supports for suspending said boxes for movement through said furnace, said track sections allowin expansion and contraction of said boxes as t e temperature varies without disengaging said convey-I or supports.

8. In combination with a heat treating furnace, article containing boxes having rims integral therewith, track sections of substantial width attached to said rims in spaced relation with the walls of said boxes, and a movable conveyor comprising a row of rollers supported in each of two oppositely disposed walls of thef'furnace for reception of said track sections whereby said boxes are supported in said furnace in suspended relation, said tracks by their width compensating for expansion and contraction of the boxes under varying temperatures whereby full support of said boxes is assured at all times.

9. In combination with a heat treating furnace, article containing boxes having rims integral therewith, track sections of substantial width keyed to said rims by means of an expansion joint, said rims always maintaining said track sections in slightly spaced relation with the walls of said boxes and a movable conveyor comprising rows of rollers supported in two oppositely disposed walls of the furnace for reception of said tracks whereby said boxes are supported in said furnace in suspended relation, said expansion joint and the width of said tracks compensating for change of dimensions of said boxes and said furnace under varying temperature to always assure proper support of said boxes in transportation through said furnace.

10. In combination with a heat treating furnace, article containing boxes having rims integral therewith, track sections of substantial width attached to 'said rims in'spaced relation with the walls of said boxes,-and a movable conveyor comprising a row of rollers supported in each of two oppositely disposed walls of the furnace for reception of said track sections whereby said boxes are supported in said furnace in suspended rela-' tion, said tracks by their width compensating for expansion and contraction of the boxes under varying temperatures whereby full support of said boxes is assured at all times, and means for limiting transverse travel of said boxes to prevent said boxes scraping the sides of the walls of said furnace.

11. In combination with a heat treating furnace, article containing boxes having rims integral therewith, track sections of substantial width attached to said rims in spaced relation with the walls of said boxes, and a movable conveyor comprising a row of rollers supported in each of two oppositely disposed walls of the furnace for reception of said track section whereby said boxes are supported in said furnace in suspended relation, said tracks by their width compensating for expansion and contraction of the boxes under varying temperature whereby fullsupport of said boxes is assured at all times and a downwardly depending flange integral with'said'track sections for limiting transverse movement of said tracks with respect to said rollers.

12. In combination with a heat treating furnace, conveyor supports therein in spaced relation above the floor of the furnace extending along the opposite walls thereof, boxes having integral portions projecting outwardly above the center of gravity thereof, track sections of substantial width attached by means of an expansion joint to said projecting portion in spaced relation to the box walls and adapted to engage said convey or supports for suspending said boxes for movement through said furnace, said track sections, because of the expansion joint and the Width thereof, allowing expansion and contraction of said boxes as the temperature varies without disengaging said conveyor support-s.

13. In combination with a heat treating furnace, article containing boxes having projecting portions integral therewith, track sections of substantial width attached to said portions inspaced relation with the walls of said boxes, and rollers in spaced relation above the furnace fioor extending along opposite walls of the furnace for engagement with said track sections for supporting the boxes in suspended-relation, said track sections by their width compensating for expansion and contraction of the boxes under varying temperatures whereby full support of said boxes is assured at all times.

14. In combination with a heat treating furnace, an upper compartment and a lower compartment, article containing boxes, a movable conveyor in said upper compartment and a movable conveyor in said lower compartment for transporting said boxes through each of said compartments, and individual means for driving each of said conveyors and means interiorly of the furnace for transferring said boxes individually from one conveyor to the other. .i

15. In combination in a heat treating furnace, an upper compartment and a lower compartment, article containing boxes, a movable conveyor in said upper compartment and a movable conveyor in said lower compartment for transporting said boxes through each of said compartments, individual means for driving each of said conveyors, means for transferring said boxes individually from one conveyor to the other, and automatic means for discontinuing the impelling means for the boxes travelling over at least one of said conveyors during the period of transfer.

16. In combination in a heat treating furnace, an upper and a lower compartment, article containing boxes, a conveyor in said upper compartment and a separately drivenconveyor in said lower compartment, a door in one end of the upper compartment for inserting said boxes onto the conveyor therein, a door for said lower compartment below said first named door and at the same end of said furnace, a passageway connecting said compartments in the opposite end of said furnace from said doors, the conveyor of said upper compartment being discontinued prior to extension over said passageway. a

roller bearing platform vertically operative in said passage, said platform when in extended position being adapted to receive the boxes from said upper conveyor, means for lowering said platform and thereby delivering boxes to said lower conveyor, said lower conveyor serving to advance the boxes toward the door of said lower compartment.

17 The combination as set forth in claim 16 together with automatic means for dis continuing movement of the boxes on said upper conveyor pending arrival of said platform to a box receiving position with respect thereto. 7

18. In a heat treating furnace, an upper compartment and a lower compartment having a connecting passageway therebetween, a conveyor for each compartment comprising rows of rollers supported in oppositely disposed walls of said compartments, article containing boxes having track carrying'rim s for suspension of said boxes on said rollers,

' the rollers in said upper compartment being discontinued at said connecting passageway, an elevator operating vertically in said passageway, rollers on said elevator for individually receiving the boxes as they leave the rollers of the upper conveyor, said elevator being adapted to lower said boxes whereby the tracks carried by the rims of said boxes rest upon the rollers of said lower conveyor which serves for advancing boxes forwardly through said lower compartment, and. means for automatically restraining movement of the boxes on said upper conveyor prior to said elevator attaining a position to receive another box.

19. In a heat treating furnace, a conveyor comprising a row of rollers rotatably supported by shafts mounted in the walls of the furnace, article containing boxes having track carrying rims for suspending said boxes on said rollers, and means for impelling said boxes over said rollers from one end of said furnace.

20. In a-heat treatment furnace, an upper compartment and a lower compartment having a connecting passageway therebetween, heat treatment boxes having laterally extending flanges, conveyor means for transporting such boxes supported from said flanges through the upper compartment,

22, In a heat treatment furnace, two chambers one over the other with a connecting end passage, heat treatment boxes having slispending means located higher than the center of gravity thereof, conveyor means for transporting boxes supported from the suspending means through the upper chamber as far as the passageway, conveyor means extending below the passage way for transporting such boxes supported from such suspending means in reverse direction through the lower furnace chamber, and means for transporting the boxes down through the passageway and delivering same into coacting relation with said conveyor means for the lower furnace chamber.

In testimony whereof I aflix my signature.

HENRY H. HARRIS.

means for transporting said boxes through the passageway, and conveyor means for transporting said boxes supported from said flanges through the lower compartment.

21. In a heat treating furnace, a plurality of furnace compartments with a connecting passage between successive compartments,

heat treatment boxes having suspending means above their centers of gravity, conveyor means for transporting such boxes supported from said suspending means through each compartment,and means for transporting the boxes from chamber to chamber through the connecting passage.