US2684681A - Conveyer and quench tank for heat treating furnaces - Google Patents

Description

y 1954 J. WALLERIUS ETAL 2,684,681

! CONVEYER AND QUENCH TANK FOR HEAT TREATING FURNACES Filed Au 24, 1949 4 Sheets-Sheet 1 July 27, 1954 J. WALLERIUS EI'AL CONVEYER AND QUENCH TANK FOR HEAT TREATING FURNACES Filed Aug. 24, 1949 4 Sheets-Sheet 2 July 27, 1 54 J. WALLERIUS ETAL CONVEYER AND QUENCH TANK FOR HEAT TREATING FURNACES Filed Aug. 24, 1949 4 Sheets-Sheet 3 4 Sheets-Sheet 4 July 27, 1954 J. WALLERIUS ET AL CONVEYER AND QUENCH TANK FOR HEAT TREATING FURNACES Filed Aug. 24, 1949 Patented July 27, 1954 A'EENT OFFICE CONVEYER AND QUENCI-I TANK FOR- HEAT TREATING FURNACES John Wallerius, Glen Ellyn, and John Ade, River Forest, 111,, assignors to Sunbeam Corporation, Chicago, 11]., a corporationof Illinois Application August 24, 1949, Serial No. 112,064

4 Claims.

This invention relates to'a heat treating apparatus and more particularly to heat treating apparatus for coil springs.

Railway and industrial springs are generally subjected to severe service and in order to insure maximum service life proper heat treatment methods must be used in the processing of springs used in'this equipment. These springs vary considerably in size from very smallsprings to extremely. large springs. :For: example the average spring used in this equipment is approximately 12 inches in free height, has a six inch outside diameter and .is formed of 11/; inch diameter stock. However a spring up to .48 inches free height and 14 inches outside diameter is not uncommon. The diameter of the stock used in springs may vary from inch to 3 inches depending on the desired stress characteristics ofthe spring. In addition to widely varying physical characteristics; the steels and alloys used in the formation of these springs also vary considerably. Due to the fact that there is a wide range in physical sizes and the alloys used .in the formation of these springs vary considerably, difficulty has been encountered heretofore in satisfactorily handling these springs during the heat'treating process. .This is because equipment that may possibly be satisfactory forone size spring isnot satisfactory for another size.

One of .the ,dimculties encountered .in heat treating coil springs is that they are veryeasily subjected to distortion during the heating and quenching operation. For example when a heated spring is dropped into a quench tank the impact of the spring againstthe fiuid in the quench tank or the bottom of the tank may cause deformation of the k, spring. Also the spring may not be quenched evenly along its longitudinal axis. To counteract the impact effect of springsrin dropping into the quench tank, cushions are-placed in the quench tank to break the fall of the springs. It is found however that even with cushions deformation of the springs still occurs. Due vto the difiiculties experienced in attempting to usemechanical means for handling coil. springs, current practice is to manually handleall springs of this type. In thecase of the small size springs, they are dumped into the quench tank andare removed therefrom manually by tongs. Larger springs are dipped into and removedfrom a quench tank by a crane. As a consequence the 2 disadvantage of the manual handling of the springs is that it requires considerable floor space and physical effort on the part of the operators.

An object of this invention is to provide a novel heat treating unit for heat treating coil springs of widely varying physical characteristics and alloy compositions.

Another object of the invention is the provision of a heat treating unit of. the above character having a novel quench tank.

Another object of the invention is the provision of a novel quench tank unit of the above character having novel means for conveying springs automatically therethrough.

Another object of the invention is the provision of a novel quench tank unit for mechanically handling coil springs.

Another object of the invention is the provision of a quench tank unit of the above character that automatically handles all coil springs in the same manner.

Another object of the invention is the provision of a quench tank unit of the above char acte'r that eliminates the manual handling of coil springs.

Another object of the invention is the provision of a quench tank unit of the above character that reduces the amount of floor space required as compared to'existing equipment.

Anotherobject of the; invention is the provision of a quench tank unit of the above character that improves the working conditions of a factory.

Another object of the invention is the provision of a quench'tank unit for heat treating springs so that the per unit cost of heat treating coil springs is greatly reduced as compared to current costs.

Other objects and advantages of'the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which- Figure 1 is adiagrammatic side elevational view of. a heat treating unit embodying the present invention;

Fig. '2 is an enlarged fragmentary sectional View .of the charge receiving end of the quench tank;

Fig. 3is an enlargedfragmentary view of the discharge end of the quench tank;

vFig. l is a plan View of the quench tank unit;

Fig. 5 is .an enlarged fragmentary sectional view of. the charge receivingend of thequench tank illustrating the position of the parts when aspring initially engages the upper belt and when a spring is gripped between the belts for advancement through. the quench tank;

Fig, 6 is a fragmentary plan view of the top conveys-r belt showing the details of construction;

Fig. 7 is a side elevational View of Fig. 6;

Fig. 8 is a fragmentary plan view of the bottom conveyor belt; and

Fig. 9 is a side elevational View of the belt shown in Fig. 8.

Referring now to the drawings the invention is shown embodied in equipment for heat treating coil springs of the type normally used in the construction of railroad and agricultural equipment. In general the heat treating equipment includes a hardening furnace I? for heat treating coil springs to the proper hardening temperature, a quench tank unit l3 for quenching the springs and a drawing furnace It for tempering the springs. The hardening furnace E2, the quench tank unit l3 and the drawing furnace I l are preferably arranged in a line so that untreated springs are fed to the hardening furnace and then pass successively through the hardening furnace, the quench tank unit and the drawing furnace in one continuous process.

For purposes of simplifying the drawings only a fragmentary portion of the hardening furnace is shown, as best seen in Figs. 1 and 2. In general the hardening furnace is of conventional construction and includes a bottom is mounted on a support and an end wall It. The latter is formed with a spring discharge opening it. Disposed within the furnace is a moving hearth 2i in the form of an endless belt. The belt is trained over suitable rollers 22 (one only being shown), positioned and supported by the side walls of the furnace to have the top of the belt 21 substantially flush with the bottom of the opening it so that articles conveyed by the belt may pass through the opening after they have been heated in the hardening furnace. An inclined chute 23 supported by the end wall it? is disposed in the opening 59 to receive the springs as they are discharged from the endless belt 2! to transfer the springs to the quench tank unit I3. As shown the chute is formed in two parts, one of which is rigid with the furnace 2 and the other being free to pivot to permit directing the springs to theproper position in the quench tank unit 13.

The drawing furnace M as best shown in Figs. 1 and 3 may also be of conventional construction. To simplify the drawings only the endless conveyor belt 26 which forms a part of the furnace is shown. The belt 26 is mounted on suitable rollers 21 (one only being shown), supported by spaced uprights 28 (one only being shown, see Fig. 3) forming a part of the frame of the furnace it. A chute 29 guides the springs from the quench tank unit l3 to the conveyor belt 26 of the drawing furnace.

One aspect of the invention is concerned with a novel quench tank unit for automatically con- Veying heated springs from the hardening furnace through a quenching fluid and delivering them to a drawing furnace in an undeformed state. To illustrate the invention the quench tank unit comprises a quench tank 3! for containing quenching fluid and a pair of endless flexible belts 32 and 33 arranged to advance the coil springs through the fluid in the tank and shaped to engage the springs to hold them against relative movement with respect to the belts while being conveyed through the tank. While the invention is shown as heat treating coil springs, it is to be understood that other objects and shapes may also be handled by the apparatus described herein. The construction of the tank is best shown in Figs. 2, 3 and 4. In general the tank is an elongated rectangular structure formed by suitable sides 34 and 36, ends 31 and 38 and a bottom 39 secured together in a conventional manner such as by welding. At the article or spring receiving end of the tank 3| the latter is formed with a sludge receiving sump. The latter is defined by a portion 40 extending below the bottom of the tank 39 and an upstanding rectangular shaped portion 3! at one side of the tank and in communication with the bottom portion 40 and the tank proper. With this construction any sludge such as scaling received in the bottom portion 40 of the sump when the articles first engage the quenching fluid, may be cleaned out from the bottom of the tank through the upstanding portion of the sump. The discharge end of the quench tank is also formed with a sump 42 formed by an upstanding portion 43 disposed at one side of the tank so that sludge may be readily removed from the tank therethrough.

The quenching fluid which may be oil, or other suitable fluid, is normally supplied to the tank 3| by a pumping system and is recirculated through the tank to maintain the quenching fluid within preselected temperature limits. Because any conventional system may be used for circulating the oil, the system is not illustrated in detail herein. Only the lines 44 and 46 forming a part of the system are shown herein. A filter 4'! is disposed in a sump d2 formed at the charge receiving end of the tank for an obvious purpose.

The belt 32 (see Figs. 4, 8 and 9) comprises a pair of spaced endless link chains 5| interconnected by spaced rods 52, the ends of which form pivotal connections for the links of the chain. Each link chain fi l is trained over a sprocket 53 and a sprocket 54 at opposite ends of the tank. The sprockets 53 are spaced apart and are mounted on a shaft 56 extending transversely across the top of the tank 31 adjacent the spring receiving end of the tank 3|. The shaft is supported by suitable bearings 57 mounted on the sides 34 and 3% of the quench tank. The sprockets 5% (one only being shown) are spaced apart and are mounted on a shaft 58 supported at the discharge end of the quench tank. The shaft 53 is supported on suitable bearings 59 (one only being shown) suitably supported on opposite sides 35 and 36 of the quench tank 3:. Wire BI is wound around adjacent rods 52 in a spiral manner. The loops of adjacent wires in passing about the rods are positioned so that they are interlocked as best shown in Fig. 8. This woven wire construction forms an endless central portion of the belt. The central portion of the belt is supported at opposite ends of the tank by spaced rollers 62 supported on the shafts 56 and 58 respectively, the rollers on the shaft 55 only being shown.

In general the belt 32 is arranged so that when observing the quench tank unit in elevation (see Figs. 1, 2 and 3) the belt inclines downwardly from the top to the bottom 3i of the tank adjacent the spring receiving end thereof, then extends horizontally through the central portion of the tank adjacent the bottom so that articles advanced therethrough are submerged in the fluid and then inclines upwardly at the discharge end of'the tank fromthe bottom to the top of the tank. Spaced elongated strips '64 having central portions adjacent the bottom 39 of the tank and their ends inclined upwardly toward the top of the tank adjacent'the spring receiving end of the tank and the discharge end of the tank serve as guides for: the lower. portion of the'belt. Suitable cross beams 166 supported on the sides 34 and 36 ofthetanklin turn support the strips. Spaced strips-=6l spaced above the strips 64 and supported by suitable'cross arms 68 serve'as a guide for theupper portion of the belt. At the discharge end of the tank an intermediate portion ofthe-stripsfi l is removed as best seen in Fig, 3. 'Th-eepurposeof this being to provide a space in'the guide's to provide 1 for slack in the endless belt'32. The portions of the strips 64 adjacent the spacing are preferably rounded so as not to interfere with the movement of the belt.

The upper belt- 33 (see -Figs.'4',-6 and '7) ls formed by spaced link chains H. The latter are supported on the quench tank by sprockets l2, l3 and 14. The sprockets-12 are-mounted on a shaft 16 supported ina suitable manner-on opposite sides of the quench tank. The shaft 16 is adjacent the spring receiving-end of the tank and rearwardly of the shaft 56 'as viewed in Figure '2 so that the forward portion of the upper belt 33 is slightly behind thefor-ward portion of the lower belt 32. The sprockets'l3 are mounted on a shaft 1! adjacent the-spring receiving end of the tank but spaced from the shaft 76. The shaft 11 is supportedby suitable bearings I8 mounted on the sides 34 and 36 of the quench tank. The sprockets 14 are mounted on a shaft 19. The shaft l9,munted at the discharge end ofthe tank, is supported by suitable bearings 8| disposed onopposite sides of the quench tank. The chain'links 'll are interconnected at spaced positions by-rods 82-extending between the spaced link chains H. The rods 82 are interconnected by interlocking spiral loops of wire as best seen in Figs. 6 and 7 to define a central woven wire portion of the chain that has flexible portions capable'ofconforming to the general configuration of an article when an article engages the belt and which normally tend to sag when supportedonly by the-rods 82 as shown in Figs. and '7. Thebelt 33 is supported so that without springs between the belts the lower portion of the belt rests freely on the top portion of the belt 32. The upper portion of the belt 33 between the sprocket l3 and 14' is supported by a suitable belt guide 84 supported by spaced uprights 80 and interconnecting cross arms 85.

The sprockets 12 are mounted for vertical movement so that the distance between the belts may be varied to accommodate diiferent sizes of springs. To this end the shaft I6 is rotatably supported at opposite ends by bearing blocks 86 (one only being shown). The blocks 66 aredisposed between generally vertically extending spaced guideways '81 rigid with sides 34 and 36 of the tank. At theirupper end' the guideways are interconnected by a bridging portion 88. Extending through the bridging portion 88 is a screw SQ'c'onnected'to'the block-86. There is a threaded connection'between the bridging portion 88and the screwso that upon rotation thereof the position of the-block 86 relative to the guidewayst'l may be varied. Thus the position of the shaft 16 aridthe- 'belt'"33" may be adjusted *toany desired *position. =A hand wheel 9| is provided for rotating each screw 1 89. To insure uniformity in movement .between the blocks 86 on oppositesidesofsthe quench tank the screws may be interconnected by an endless link chain 32 trained over a sprocket 93 rigidly supported on each screw 89. With this construction rotation of one handwheel al effects simultaneous movement of theblocks 86.

Suitable provision is made for driving the belts 32 and '33. 'In' this instance thebelts are driven simultaneously by a motor 98'. .As shown the motor is'mounted one-platform 99, on top of the quench tank 3| adjacent the discharge end thereof. The motor 98 is'connected to a variable speed unit IN. "The variable speed unit is connected to a'speed reducer't02 by a V belt 103. The speed reduceris disposed in side by side relation'with the motor and'is rigidly secured to the platform-'93. The speed reducer is drivingly connected to-theshaft 56 by a link chain [64 trained over-sprockets I06 and I0! mounted respectively on the shaft '58 and a shaft I05 on the speed reducer unit. A spur gear I03 mounted on the shaft 58 meshes with a spur gear III on the shaft 18 so that the upper sprockets l4 and the lower sprockets 54 are driven in unison.

Provision is made for simultaneously driving all of the sprockets I2, 13 and '14. For this purpose a chain link I I2 is trained over a sprocket H3 rigid with the shaft 19 and a sprocket H4 rigid with the shaft 11 to provide a driving connection betweenythe shafts 19 and 11. In a similar manner a sprocket H6- rigid with the shaft 11 and a sprocket ll! rigid with the shaft I6 are interconnected by a link chain H8 to form a driving connection between the shafts H and 76. A sprocket l I 9 rotatably mounted on an arm l2l secured to the side of the quench tank maintains the proper'tension in the link chain H8 between the sprockets 76 and 11.

As best shown in Fig. 2 a certain amount of slack exists between the sprockets 13 and 12. The slack is necessary in order topermit the sprocket 72 to be elevated, thereby varying the distance between the belts 32 and, 33 to accommodate different sizes of springs. .By driving the sprockets I2 and 13 as well'as the sprocket 14 it is found that the slack between the sprockets l2 and 13 remains the same; that is, the belt is moved uniformly. and the tendency to pile up or have a jerky'movement is eliminated.

The operation of the foregoing construction is as follows. The. coil springs are normally introduced into the hardening furnace 12 where they are heated up to the proper'temperature asthey are conveyed along by the hearth 21. When the springs are heated tothe required temperature they are discharged through the opening l9 and roll down the chute 23 on to the lower belt 32 which extends forwardly. slightlytof the belt 33 at the spring receiving end of the tank. The belt 32 at the spring receiving end of the tank is inclined so that when the springs leave the chute 23 they tend to roll down the inclined upper surface of .the lower belt 32. Simultaneously the'belt is moving through the tank. As a spring rolls downwardly into the tank 3| it becomes submerged in the quenching fluid. Shortly after submergence in the fluid the upper forward surface of the spring engages a downwardly extending or-saggingiportion ofthe upper belt 33 as shown in Fig 5. :The sagging, portions of the belt 33 are relatively flexible and when the spring contacts it the flexibleportionengaged bythe spring tends to conform to the configuration of the spring. The flexible portion of the belt in contacting the spring acts as a drag on the spring and tends to retard its motion. The forward motion of the spring may carry it past the first or second sagging portions that it engages but each sagging portion that the spring engages retards the relative movement of the spring with respect to the belts. The force exerted between the flexible portions of the belt and the spring is very small so that the spring is not deformed when it contacts the flexible portions of the belt. Since the lower portion of the upper belt 33 normally rests on the upper portion of the belt 32, it will be apparent by observation in Fig. that when the spring submerges sufficiently in the tank it eventually engages a sagging portion of the upper belt wherein the contact between the spring and the belt is such that the flexible portion conforms to the configuration of the upper portion of the spring and in efiect defines a pocket for receiving the spring. The relative position of the parts under these conditions is shown in Fig. 5 (see lower spring). Under these conditions the lower spring is gripped between the belts. When the spring gripped between the two belts in this manner the spring is held against relative movement. Since both belts are moving simultaneously in a uniform manner the spring is advanced through the quench tank in a uniform manner. After the spring is quenched the spring is discharged from the quench tank through the chute 29 to pass on to the conveyer 26 of the furnace it.

By driving all the sprockets l2, l3 and I5, uni form movement of the upper belt 33 is assured. Also both belts 32 and 33 are driven from a single power source and consequently moves in unison through the tank so that there is no pressure or force exerted on the springs due to diiferent speeds of travel of the belts. The adjustment of the sprockets l2 permits different sizes of springs to be handled in the quench tank. The conveyance of springs through the unit is antomatic and does not require the intervention of an operator or manual handling of the springs. Moreover, each spring is handled in exactly the same way so that the stresses in each spring of a given size are uniform. Since the handling of the springs is automatic it is evident that the cost of treating the springs is greatly reduced as compared to. processing springs by manual methods.

While there has been illustrated and described a particular embodiment of the present invention, it is not desired that the invention be limited to the construction shown and described, for it will, of course, be obvious to those skilled in the art, that changes and modifications may be made without departing from the present invention in its broader aspects and it is, therefore, aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the present invention.

We claim:

1. For use with a quench tank unit of the type comprising a tank for containing a quenching fluid, first spaced sprockets at oppoiste ends of the tank, first spaced endless link chains supported by said sprockets and passing through the fluid. in said tank, a flexible belt between said link chains and supported thereby, second spaced sprockets at opposite ends of the tank in spaced relation respectively to the first spaced sprockets,

second spaced endless link chains supported by said second spaced sprockets to have portions in overlying relation with said first endless link chains, a second endless flexible belt between said second spaced endless link chains to be in overlying relation with said first flexible belt to engage opposite sides of an article to advance it through the quenching fluid, said second endless belt being supported by said second spaced endless chains at spaced positions to have portions of the belt between said points of support longer than the distance between said spaced positions whereby said portions are flexible from one side of the plane of the support points on the chains to the other upon engagement with an articl to define a pocket for receiving the article to hold the article against relative movement as it is advanced through the fluid between the belts.

2. For use with a quench tank of a type containing a quenching fluid, the combination of first and second endless belts mounted on said tank, one of said belts being in overlying relation to the other to have a portion of the upper belt coact with a portion of the lower belt to convey an article through the quenching fluid, the upper belt having spaced flexible portions longer than the distance between the means supporting said spaced flexible portions whereby said flexible portions normally tend to sag and are flexible to conform to the configuration of an articl when brought into contiguous relation therewith and means for supporting the upper belt with respect to the lower belt whereby when an article initially moves into engagement with the upper belt the sagging flexible portions engage the article and act as a drag to retard movement of the articl relative to the belts before the article is gripped between the belts for advancement trough the tank.

3. For use with a quench tank unit of the type comprising a tank containing quenching fluid and having an article receiving end and an ar ticle discharge end, the combination of a first belt, means for mounting said belt on said tank to have a central portion adjacent the bottom of the tank, an end portion inclining upwardly from a position adjacent the bottom of the tank to the article receiving end and an end portion inclining upwardly from the position adjacent the bottom to the article discharge end, a second belt, means for mounting said belt to have the extreme end portion of the belt spaced above one end portion of the first belt and having a central portion of the belt normally resting on said first belt, said second belt having spaced flexible portions longer than the shortest distance between the ends of said flexible portions, said flexible portions adapted to sag at the article receiving end of the tank and positioned to be engageable by an article moving down said inclined portion of the first belt at the article receiving end of the tank to arrest movement thereof relative to the belts and said flexible portions adapted to conform to the configuration of an article to define a pocket for holding the article against relative movement as it is carried down into the tank, lengthwise of the tank and upwardly to the article discharge end of the tank.

4. For use with a quench tank containing a quenching fluid and having an article receiving end and an article discharge end, the combination of a first endless belt, means for mounting said belt to hav an end portion adjacent the article receiving end and an opposite end portion adjacent the article discharge end, a second endless belt, means for mounting said belt to have a first end portion spaced above and away from one end portion of said first endless belt and a second end portion spaced relatively far above the second end portion of the first belt and having a central portion resting on the first endless belt, said second endless belt having spaced flexible portions longer than the shortest distance between the ends of said flexible portions, said portions adapted to sag toward the second endless belt at the article receiving end of the furnace and positioned to be engaged by an article moving relative to the end of the first belt adjacent the article receiving end to arrest movement of the article and said flexible portions adapted to conform to the configuration of the article to define a pocket for holding the article against relative movement with respect to the belt as it is moved through the tank, and means associated with the mounting means of one of said belts for adjusting the spacing between the ends of the belt adjacent the article receiving end.

References Cited in the file of this patent UNITED STATES PATENTS Number Number 20 24,360 503,174

Name Date Knott Mar. 11, 1902 Kranz Mar. 8, 1910 Cwirko June 14, 1921 Brennan July 11, 1922 Smallidge July 10, 1928 Engel Jan. 8, 1935 Jacobsmeyer Mar. 31, 1936 Guba Dec. 28, 1937 Grow Sept. 12, 1939 Guba June 3, 1941 Rose Sept. 2, 1941 Loux Mar. 16, 1948 Enkur et al Aug. 23, 1949 FOREIGN PATENTS Country Date Norway 1 Jan. 20, 1913 Germany July 28, 1930

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