US1782451A - Heat-treating furnace - Google Patents

Description

NOV. 25, 930, H, 1 WAISNER l 1,782,451

HEAT TREATING FURNACE Filed NOV. 7, 1927 4 Sheets-Shee l Nov. 25, 1930, H, WMSER 1,782,451

HEAT TREAT ING FURNACE Filed Nov. 7, 192'? 4 Sheets-Sheet 2 aonnogo @Qoaonoo 11m/Emma ATTYS H. L.. WAISNER 1,782A

HEAT TREATING FURNACE Nav. 25, w30.

4 Sheets-Sheet 5 INvENTma BY wmrmw ATTYS Nov. 25, 1930. H. l.. WA-lsNER HEAT TREATING FURNACE Filed Nov.

7, 1927 4 Sheets-Sheet 4 INvENT'oR ATTYs tlon,

Patented Nov'. 2s, reso UNITED STATES PATENT OFFICE HORAGE L. WAISNER, OF ROCKFORD, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO MECHANICS UNIVERSAL JOINT COMPANY, OF ROCKFORD, ILLINOIS, A CORPORA- TION OF ILLINOIS HET-TRFATING FURNACE Application led November 7, 1927. Serial No. '231,639.

I This invention relates to heat treating furnaces generall but has more particular reference to one aving a mechanical feed and adjustable to accommodate differentl sizes or 5 kinds of work.

The principal object of the present invention is to provide a furnace for local heat treatment purposes which, while designed to produce and maintain therein a high thermal head for theproper heating of the part or parts of the work equiring such treatment, is so designed thatF the rest of' the work is shielded and remains entirely unaffected by heating.

15 Work requiring local heat treatment, as in the case of trunnions on the arms of anniversal joint yoke, presents a rather difficult problem in that where theiheating is too sudden there is danger of cracks developing or severe strains being set up, whereas where the heating is slower there is danger of having more of each work piece affected by the lheat treatment than is desired as a result of the heat being dissipated from the portion to be heated. For example, when the trunnions were heat treated by dipping the yokes in molten lead, cracks developed in the arms thereof and many yokes failed to pass inspection for that reason. Hence the necessity for slower heatin became evident. The present furnace, as lereinafter des'cribed, permits slower heating without danger of heat dis" sipation from the parts where the heat treatment is desired to those parts which should not be, heated.

, Another, important object of the invention resides in the provisionof means in the nature of bailles serving to direct the heat toward the part or parts to be heated, the said balies being so arranged as toshield the rest of the work.

Still another important object lies in the provision of means whereby the baiiles. as well as the mechanical feed, may be quickly and easily adjusted for the handling of differenty jobs. For example, universal joint yokes, which happen to be the articles under special consideration in. the present invenare made in various sizes for different being heated to other portions not intended' sized cars ortrucks, and a sin le furnace as herein constructed may, by slig be made to handle any size which may be encountered.

The invention embraces various novel feat-ures which will be brought out in the course of the following specification in which reference is made to the accompanying draw ings, whereinq Figure 1 is a side view of my improved heat treating furnace;

Fig. 2 is. a central, vertical, longitudinal section through Fig. 1v with the lower part of the frame broken away;

Fig. 3 is an enlarged cross-sectional view on the line 3-3 of Fig. 2;

Fig. 4 is anenlarged fragmentary side elevation of one of the universal joint yokes in its holder, illustrating the novel form of tips employed on the holder;

Fig. 5 is a left hand'end view of Fig. 2; and

Fig. 6 is a rather diagrammatic view in secv tion to better illustrate the action of the baiiles inside the furnace and to indicate their adjustability as well as the adjustability of the Work piece with the mechanical feed, andy to illustrate the action of the air blast.

t adjustment, i

The same reference numerals are used throughout the views to indicate corresponding parts.

The furnace of my invention, as stated above, embodies various features, some of which have special utility is used in the heat treating of universal joint yokes. However, it will be understood that these and other features incorporated in the furnace might be used for the general run of local heat treating. The furnace, in other words, might be modified from its present special construction in various minor details to suit the requirements of any articular work which it may be desired to lieat treat and, for the most part, it will be evident that in such cases the present invention need not be seriously departed from. No limitation should, therefore, be regarded as imposed on the present invention by reason of any reference herein to its use in the heat treating of universal joint yokes.

- Before proceeding to a description of the where the furnace yals one example herein illustrated of the kind ofl heat treatlng operation which the same is capable of performing, namely,

universal joint yokes 10. When these yokes were dipped in molten lead for the heat treatment of the trunnions, the arms 9 were frequently found to have cracks developed therein as a result of the too sudden heating. According to the present invention, care is taken to avoid the heating of the arms 9 and to confine the heating to the trunnions; the arms 9 and the rest of the body part of the yoke being cooled so as not to be affected by the heatmg of the trunnions by reason of any conduction from the trunnionsthrough the arms. The arms are shielded during the heating of the trunnions and an air blast is played onto the body of the yoke to keep the temperature thereof as low as possible. The yokes are forged and then practically corn- Y pletely machined, only the trunnions being left slightly oversize. hey are then heated at suitable temperatures following which they are quenched `and then tempered to relieve any strains which might exist therein. After this, the trunnions are ground to size and the yokes are ready for use. The aim in this neat treatment, according to the present invention,

is to avoid too sudden heating and any other conditions which might tend to develop cracks or abnormal strains. Such slight strains as are set up as a result of this heat treatment are easily relieved in the tempering operation which immediately follows.

The shell or casing 11 of the furnace is supported on a frame or base 12, the latter affording a place for the support ofthe driving motor 13, variable speed gear box 14, and reduction gear casing 15, furnishing the power for the driving of the mechanical vfeed for feeding the work through the furnace at the desired speed. Chain driving connections for the chain conveyor 16 are indicated at 15 and 15". The variable speed gearing in the box 14 permits of whatever variation in nthe rate of travel of the conveyor may be deemed advisable for diierent jobs. The work is placed in the holders 17 byan attendant standing at the front of the furnace (the left hand end as seen in Fig. 1) and is removed with tongs by an attendant standing at the back of the machine who also takes care of the quenching thereof. The work is carriedv on the holders 17 through anI elongated rebox or heating chamber 18 extending lengthwise of the furnace and duringits travel is subjected, on both sides, to the action of the gas llames from the burners or nozzles 19 mounted in the opposite side Walls of the furnace. The yokes travel in the manner shown most clearly in Fig. 2 with the trunnions disposed in the direction of travel, thus presenting the the heat treatment of the trunnions 8 on the arms 9 of in passing through the furnace.

trunnions broadside to the action of the burners. The flames from the burners, as shown 'in Fig. 6, are deflected upward ly on the inclined tops of baiiles 2() and are thus caused to envelop the trunnions, the spent gases being allowed to escape through due openings 21 provided direct y over the path of travel of the y kes in the top of the heating chamber. The bailles 20 extend lengthwise of the heating chamber 18 and are disposed at opposite sides thereof, as shown, so that the yokes travel therebetween The bafin addition to directing the flames pro also serve to shield t e latter in a manner believed to be self-evident from the diagrammatic showin in Fig. 6. The heating is, therefore, con ned almost entirely to the trunnions. In addition to minimizing the heating of the bodies of the yokes l also provide an air blast manifold 22 which delivers air -ets from beneath into the heating chamber to play onto the yokes so that the bodies and arms thereof are kept below their lower critical temperatures and therefore are not-hardened upon quenching. The air discharged from the manifold 22 is directed in a line toward the fines 217 thus aiding the draft for the burners 19. The products of combustion are entrained with he` air as `it passes -upwardly through the ues.

The furnace is lined with firebrick 23, the flue openings 21 being formed therein in the manner' indicated. Fire clay is also used in the construction of the inside of the furnace, as indicated at 24. The gas nozzles 19 are introduced through openings in the walls of the furnace and are suitably provided with special tips 25 which give good flame distribution. The nozzles are threaded at their outer ends as at 26, for reception in the openings 2i provided in evenly spaced relation along he inside wall of each of the manifolds 28. The outside wall of each manifold is provided by a back plate 29 removably xed thereon so that access may be had to the nozzles, the latter being arranged to be screwed into and out of place by use of a screw driver, the slots for which appear in the'drawing. The nozzles are removed from time to time' for inspection and cleaning or replacement of the tips; hence the provision of the removable back plates is of considerable advantageQGood gas distribution to all of the nozzles is also insured by having the gas supply pipes 30 delivering into the manifolds at points spaced evenly longitudinally of the manifolds. The condition docs not arise where some of the nozzles, as for example at the ends ofthe manifolds, are starved more or less. The uniform gas distribution, ofcourse, makes for uniform heating which is of great im ortance. The valves 31 are provided to regu ate the flow of gas in fles, erlv onto the work order that the desired temperature may be maintained in the furnace. vThe three pipes for each manifold are .suitably connected in common to an air and gas mixer in order to produce Bunsen flames at the burners 19.

Equal distribution of the air discharged from the manifold 22 is secured in a somewhat similar manner as in the distribution of the gas. The manifold 22 has a series of evenly spaced jet openings 32 in the wall thereof along one side. A pipe V33 is sealed in one end of the manifold 22 and extends therein substantiall the full length thereof and has a number ofy relatively widely spaced openings 34 providedin the wall thereof along one side diametrically opposite from the openings-32 in the wall of the' manifold 22. The inner end ofthe pipe 22 is suitably closed to insure discharge ofthe air at the openings 34 into the manifold 22. Air is supplied to the pipe 33 through a hose connection 35 communicating with the outer end of the pipe. Uniform distribution is secured in the discharge of the air through the openings 32 since the discharge is in no way confined to the immediate locality of the openings 34 in the pipe 33. The discharge of the air is, furthermore, fairly gentle and not with ,as much force as might be implied by the use of the expression air blast. Only sufficient air is supplied to insure the keeping cool of the bodies and arms of the yokes.

The conveyor 16 operates over a drive sprocket 36 and an idler sprocket 37, the latter being adjustable with relation to the former in order to take up slack in the conveyor. The brackets 38 and 39, which provide mountings for the sprockets 36 and 37, are carried on the ends of guide rails 40. Angle iron strips 41 ixed on the upper ends `of the rails .40 provide guideways between the inturned iianges thereof and the upper edges of the guide rails 40, as indicated at 42, for the sli ing reception ofshield plates 43, one of which is provided for each of the work holders 17 and extends substantially from opposite sides of the conveyor chain to be received at its lateral edges in the guidewa s 42. The plates 43 are called shield p ates for the reason that they have openings 44 therein at only a central point to permit the air blast to reach only the bodies and arms of the yokes and not the trunnions. The plates 43,l however, serve also by their travel through the guideways 42 to keep the work holders 17 moving along a straight and even path of travel. Thus, the exposure of the trunnions in the heating chamber is uniform from end to end thereof. The amount of exposure desired ob viously depends on the size of the trunnions and since there is an appreciable variation in the size of trunnions for dierent sized universal joint yokes, I have rovided means for adjusting the elevation o the guide rails 40.y The adjustment of the latter will, of course, result in the adjustment of the conveyor as a unit and all of the work holders will consequently be adjusted to an equal degree to vary the amount of exposure of all of the work pieces inthe heating chamber to precisely the same degree. It vwill be observed that the guide rails have bolts 45 extending through slots 46 in lugs 47 provided on the members of the frame 12. These bolts serve to guide the rails 40 for up and down movement and preventendwise displacement thereof. A pair of cams 48 is provided on each of two shafts 49 and 50. A lever 51 is fixed to the shaft 49 to permit the turning of the cams to secure the desired elevation of the guide rails, the two i shafts 49 and 50 being interconnected by a link 52 and levers 53 and 54 so that the turning of one shaft causes the vturning of the other. A ratchet gear 55 fixed on the shaft 49 has a pawl 56 engaging the same to serve in holding the cams 48 in any desired state of adjustment. The change in exposure of each work piece resulting from the adjustment of the guide rails-is indi-4 cated in dotted lines in the diagram of Fig. 6 where the yoke 10 is shown in full and dotted lines.

When the elevationk of the conveyor is changed some slight adjustment of thebafiles 20 is usually necessitated, as indicated in dotted lines in Fig. 6. The bullies, it will be observed, have the body portions thereof made of firebrick mounted on metallic base pieces 57 and held in place by plates 58 and angle irons 59. The adjustment of the bafiles may be made bythe operation of rods 60 attached to the base pieces outwardly through tubular guides 61 for connection with levers 62 pivoted on the outside of the casing 11. The levers 62 engage ratchet sectors 63 to hold the same in any position of adjustment. Two levers are preferably provided for each baille, one at each end thereof (see Fig. 1). Thus, the same amount of adjustment may easily be made at both ends of the baies and the bafies 1will, therefore, be kept/ substantially paral e The lbase pieces 57 of the bales are suitably cast to provide longitudinally extending Water-' circulatin passages 77 and 78 in communication witg one anotherI at one end thereof, as indicated at 79, and having inlet and outlet hose connections and 81 comm'unicating therewith at the other end. The inlet hoses 80 are suitably interconnected by a T fitting and the outlet hoses 81 likewise in order to simplify the water cooling system. The flexibility of the hose connections obviously permits of the adjustment of the bales toward and away from one another, as

57 andl extendingl above described. The baies, by reason of the water cooling, are protected from overheating under the direct play of the gas flames thereon.

The inlet and outlet ends of the furnace are closed by end plates 66 and 67, respectively, which have openings, as indicated at 68, for the water hose connections and central openings 69 to permit the passage therethrough of the work holders 17 with the yokes in place thereon. Bolts 70 serve to fasten the plates 66 and 67 in place on the ends of the casing 11. When the furnace is being adjusted to operate on a run of larger or smaller yokes, the end plates 6 6 and 67 are removed and other end plates substituted having the proper sized openings 69 therein. The thought is to avoid, as much as possible, any indrafts of cold air or escape of heat through thei openings at the opposite ends of the furnace.- The bolt holes in the plates 66 and 67 are provided slightly elongated so that the plates may be set to give the work the proper clearance in entering and leaving the furnace.

The tops of the bales 20, as clearly appears in Figs. 3 and 6, are conformed to provide fiat ledges S2 at the lower end of the inclined portions 83. Any dirt or dust during the operation of the furnace will tend to collect on these ledges. IThe end plates 66 and 67 have sight openings 84 provided therein in line with the ledges through which the accumulation of dust and dirt can be observed and through which an air nozzle may be entered to permit the same to be cleaned out. Covers 85, swingable out of the way. serve normally to close the sight openings. lVhere the baffles are brought together as, for example, as shown in dotted lines, in Fig. 6, there is a likelihood of some dirt and dust dropping down from the ledges 82 onto secondary ledges 82 provided by the angle irons 59. When that occurs the air nozzle may be introduced through the openings 68 in the end plates 66 and 67 (see Fig. 5) to clean out such dust and dirt. Obviously, keeping the furnace clean makes for generally more eicient operation. f

In Fig. 4, I have illustrated tips 71 which are arranged to be mounted on the arms 7 2 of the work holders 17 to engage and support the yokes just beneath the trunnions thereof in the manner clearly shown in igs. 2-4. The tips 71 are slightly relieved at the ends thereof, as indicated at 73 in Fig. 3, to form seats for the trunnions for the better holding thereof. The free ends of the tips are also offset, as indicated at 74, to provide flat portions to rest in engagement with the sides of the yokes beneath the trunnions. The end portions of the tips are of considerably reduced cross section, as most clearly appears in Fig. 4, for the urpose of minimizing the heat conduction rom the trunnions to the arms of the work holders. A pair of openings 75 is provided in each half of the length of the tip to permit the fastening of the tips in either of two positions as by means of rivets 76. Thus, after a new set of tips has been in service for a certain length of time and the ends thereof which have been exposed to the heat in the furnace have burned off more or less, the tips may be removed, reversed end for end, and fasten( d in place again so that the other ends thereof may be used. An appreciable saving in maintenance expense is thereby derived.

I claim:

' 1. A heat treating furnace comprising, in combination, a casing providing an elongated heating chamber therein, an endless conveyor operating through said casing having means thereon for holding work to feed a portion of th same through the casing, means for directing flames onto the work from both sides as the same is fed through the casing, means so disposed as to shield a part of the work on both sides thereof from the action of said flames, comprising baies arranged to direct the flame toward the part or parts of the work to be heat treated while at the same time serving to shield the rest of the work.

2. The combination as set forth in claim 1 wherein the last mentioned means comprises baffles arranged to direct the flames upwardly toward the part or parts of the work to be heat treated, the said bales being adjustable horizontally toward and away from one another to suit the work being handled and wherein the endless conveyor is adjustable vertically to vary the amount of exposure of the work in said casing above said batlies.

3. In a furnace of the character described, a casing providing an elongated heating chamber therein, an endless conveyor operating lengthwise of said chamber for feeding work therethrough to be subjected to heating therein, the said conveyor extending beyond the inputl and output ends of said chamber at the ends of said easing. means on said conveyor for holding the work pieces so that only a part of each is exposed for heating in said chamber,

tending beyond the ends of the casing for supporting the conveyor, and means for adjusting the last mentioned means relative to the frame whereby to adjust the conveyor in relation to the heating chamber so asv to change the amount of exposure of the work pieces therein.'

4. A furnace as set forth in claim 3 including air blast means disposed lengthwise with respect to the. conveyor for delivering air onto the unexposed parts of the work pieces to keep the same cool, said air blast means being adjustable with the conveyor whereby to maintain a predetermined relationship therea frame supporting the casing, means carried by the frame and ex` with regardless of adjustment ofthe con-` veyor with 1ts lsup ort. g

5. A furnace o the character described com rising a casing providing an elongated heating chamber therein, a support for the casing, an endless cha-in conveyor beneath said casing operating lengthwise of the heating chamber, work holders mounted on said conveyor and extending up into the heating chamber while traveling along the upper flight of the chain conveyor, said work holders being arranged to support work pieces so that a part of each is exposed in the heating chamber a guide on said support for the upper flight of the chain conveyor to insure the same amount of exposure of each work iece throughout the travel thereof in the eating chamber, and means for adjusting the elevation of the guide with relation to the support whereb to vary the amount of exposure of the wor pieces in the heating cham: ber.

6. A furnace as set forth in claim 5 wherein the last mentioned means comprises apair of cam shafts mounted on the support and having the guide resting on the cams thereof, the guide being held against endwise movement with relation to the support but uided for vertical movement with res ect thereto, a hand lever attached to one o said shafts for turning the same, means extending between the shafts to transmit rotation from one to the other, and means for holding said shafts in adjusted osition.

In a furnace o the character described, an air blast device comprising an air supply pipe, and a tubular manifold extendingsubstantially the length of the pipe and having the latter sealed therein, the pipe having several relatively lar e air discharge openings in the wall thereo along one side and having the inner end thereof closed and the outer end thereof arranged for connection with an air supply means, and said manifold having a plurality of closel spaced relatively small air jet openings in t e wall thereof along one side, the last mentioned openings being disposed in diametrically opposed relation to the lirst mentioned openings substantially as and for the purpose describ-ed.

8. In a furnace of the character described, the combination of an elongated chamber, means operating lengthwise of the chamber for feeding work therethrough to be subjected to heating therein, only a certain part of each ,work piece being exposed in said chamber, means in said chamber for heating the exposed arts, and means disposed longitudinally o the ath of movement of the worlr pieces for deliverin an air blast onthe work pieces during t e travel thereof through the heating chamber to keep cool the unexposed parts of the work pieces.

9. In a furnace of the character described, a casing providing an elongated heating chambery therein, lengthwise of the at opposite sides of the heating a work carrier operating heating chamber, burners chamber, ar-

ranged to have the flames thereof played onto the opposite sides of the passes through the chamber, baliies at opp work as it s1te sides of the chamber between which the worlg is arranged to pass, said baffles serving to direct the Haines against the part of the Work to be heated and to sh ield the rest thereof, and means for delivering an air blast between the bailles against the unexposed part of the work, said heating chamber being4 closed on top over the baffles to confine the flames of the burners to the the work but beingprovided exposed part of with a Hue openmg in line with the air blast means so that the air discharged from the l through the flue opening and products of combustion from th 10. In a furnace of the charac a casing providing an elong chamber t erein, lengthwise. of the at opposite sides of the ranged to have the the opposite sides heating a work carrier heating chamber, burners atter escapes entrains the e burners.

ter described, ated heating operating chamber, ar-

iiames thereof played onto of the work as 1t passes through the chamber, baliies at opposite sides ofthe chamber between which the work is arranged to pass, said baliles serving to direct the flames against the be heated and to shield means for delivering an baiiies against the unexposed part of the work to the rest thereof, and air blast between the part of the Work, said burners being disposed in a plane below the exposed art of the work to be heated and said bales being upwardly inclined from the burners toward the work to deflect the flames upwardly so that they pla Vproperly onto the exposed part of the wor to be heated and being directed away from the rest of the work that is not said heating chamber having a ii the top midway between the bu rectly over the Work to conduct of combustion away from the b 11. Ina furnace of the charac a casing providing chamber therein, a

at opposite sides of the heating to be heated, ue opening in rners and dithe products urners.

ter described,

an elongated heating work carrier operating lengthwise of the heating chamber,

burners chamber, ar-

ranged to have the ames thereof played onto the opposite sides of the work as it passes through the chamber, bailies at opposite sides of the chamber between which varranged-to pass, said baliles s rect the flames against the part to be heated. and to shield the the `work is erving to diof the work rest thereof,

means for delivering an air blast between thebailles against the unexpose Lawork, and means disposed bet d part of the Ween the air blast means and the work to shield a part of the work from the air blast so th air is played only on the par at the cooling t thereof intended to be cooled and not on the part being heat treated.

12. In a heat treating furnace comprising a conveyor having .work holding devices thereon for holding work pieces in the heating zone of the furnace for heat-treatment, the work pieces having only that part thereof exposed which it is desired to heat treat, tips on the work holders for supporting the Work pieces, each of said ti s having one part thereof arranged to be astened on the work holder and having the other part thereof arranged to support the work piece, only the latter part being exposed in the heatin zone of the furnace 1n operation, said tips eing reversible end for end and arranged to be held in either position on the Work holder for the purpose described.

13. A heat treating furnace comprising, in combination, a casing providing an elon gated heating chamber, a mechanical conveyor operating throngl ing work therethroug means for directing flames toward the'work, an inclined bale for delecting the flames onto the part or parts of the work to be heat treated, there being a led e whereon dust and dirt from Within the casln and o' the baille is arranged to collect, t e casing having openings 1n the end walls thereof in line with said ledge permitting inspection of the inside of said casing and the introduction whereby to clean out accumulated dust and dirt from said ledge, and means normally closing said openings.

14. A heat treating furnace comprising, in combination, a casing providing an elongated heating chamber therein, a mechanical conveyor for feeding work through said casing, means in the opposite side Walls of said casing for directing flames onto the opposite sides of the work, a pair of bales at opposite sides of said conveyor in said casing for delecting the flames toward the part or parts of the work to be heat treated, and means for adjusting each ofr said baffles comprising rods attached thereto and extending outwardly through the side walls of said casing, levers pivoted on the outside walls of said casing and connected to said rods to reciprocate the latter, and means for detachably holding the levers in adjusted osition.

In witness of the foregoing aix my signature.

HORACE L. WAISNER.

said casing for feedy

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