US2848213A

US2848213A - Heat treating machine

Info

Publication number: US2848213A
Application number: US513936A
Authority: US
Inventors: Quentin M Bloom; Samuel H Herman
Original assignee: Selas Corp of America
Current assignee: Selas Corp of America
Priority date: 1955-06-08
Filing date: 1955-06-08
Publication date: 1958-08-19
Anticipated expiration: 1975-08-19

Description

1958 Q. M. BLOOM Erm. 2,848,213

HEAT TREATING MACHINE 6 Sheets-Sheet 1 Filed June 8, 1955 INVENTORS. QUENTIN M. BLOOM SAMUEL H. HERMAN ATTORNEY Aug. 19, 1958 Q. M. BLOOM EII'YAL 2,848,213 I HEAT TREATING MACHINE Filed June 8, 1955 6 Sheets-Sheet 2 INVENTORS. QUENTIN M, BLOOM BY SAMUEL H. HERMAN ATTORNEY.

1958 Q. M. BLOOM El'AL 2,848,213

HEAT TREATING MACHINE 6 Sheets-Sheet 3 Filed June 8, 1955 INVENTORS. QUENTIN M. BLOOM SAMUEL H.HERMAN ATTORNEY.

Aug. 19, 1958 Q. M. BLOOM irrAL ,2

HEAT TREATING MACHINE Filed June 8, 1955 6 Sheets-Sheet 4 INVENTORJ'. QUENTIN M. BLOOM BY SAMUEL H. HERMAN ATTORN EY.

Aug. 19, 1958 Q. M. BLOOM EI'AL 2,

HEAT TREATING MACHINE Filed June 8, 1955 6 Sheets-Sheet 5 FIG.8

ATTORNEY.

Aug. 19,1958 M, BLOOM HA 2,848,213

I -IEAT TREATING MACHINE 6 Sheets-Sheet 6 Filed June 8, 1955 wfi m w M O M w m a w T m E n u o N B H n n m n n W N M H m m I N L n l E m w m U n n E M u u WM u n N9 1 -L ATTORNEY.

United States Patent HEAT TREATlNG MACHINE Quentin M. Bloom, Huntingdon Valley, and Samuel H.

Herman, Philadelphia, Pa., assignors to Selas Corporation of America, Philadeipliia, Pa., a corporation of Pennsylvania Application June 8, 1955, Serial No. 513,936

14 Claims. (Cl. 2664) The present invention relates to the heat treatment of hardenable ferrous metal articles, and more particularly to apparatus by means of which said articles are moved continuously through a path along which are located pieces of apparatus that successively perform various steps in the heat treatment of the article.

The present invention includes an endless conveyor that has attached to it a plurality of work supporting members upon which the pieces to be heat treated are mounted. These members are moved to dilferent positions with respect to the conveyor at various points along the conveyor path in order to facilitate the handling of the work as well as to locate it properly for the various steps of the heat treatment that are performed upon it.

The apparatus is designed to handle articles of various shapes and compositions. It is particularly designed, however, for use in the heat treating of shell blanks after forging, and, by way of example, will be described as being used for that purpose.

It is a specific object of the invention to provide a machine for heat treating shell blanks from the residual forging heat.

It is an object of the invention to provide a machine which will handle articles to be heat treated, and to move them in sequence through a path where different operatiOns are performed on them at different stations along the path. It is a further object of the invention to move metallic objects through a path and at sequential stations in the path, even out their temperature, quench them, temper them and cool them in a plurality of steps.

Another object of the invention is to provide a conveyor for moving objects through a path in which the object supporting portions of the conveyor are tilted to various positions to facilitate placing the objects thereon and to carry them through the work zones in the proper position with relation thereto.

A further and more general object of the invention is to provide apparatus for heat treating individually a plurality of metallic objects, one after the other, in a duplicate fashion.

The various features of novelty which characterize our invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specific objects attained with its use, reference should be had to the accompanying drawings and descriptive matter in which we have illustrated and described a preferred embodiment of the invention.

In the drawings:

Figure 1 is a plan view showing the entire apparatus;

Figure 2 is a view taken on line 2-2 of Figure 1 showing the conveyor driving mechanism;

Figure 3 is a view taken on line 3-3 of Figure 2 showing a portion of the driving mechanism in plan;

Figure 4 is a viewtaken on line '44 of Figure 2 showing one side of a portion ofthe conveyor;

Figure 5 is a view taken on line SS of Figure 1 showing the loading platform;

Figure 6 is a view taken on line 6-6 of Figure 1 showing a portion of the balancing furnace and the quench tank;

Figure 7 is a view taken on line 7-7 of Figure 1 showing a section through the tempering furnace;

Figure 8 is a view taken on line 88 of Figure 1 showing the section through the air cooling mechanism;

Figure 9 is a view taken on line 99 of Figure 1 showing a section through the water cooling apparatus, and

Figure 10 is a view taken on line 10-10 of Figure 1 showing the discharge platform.

Reference is first made to the plan view of the entire apparatus in Figure 1 wherein the position of the various parts with relation to each other is shown. The various work pieces that are to be operated upon by the apparatus are moved through a path on a conveyor 1 that is guided by idler sprockets 2 and 3 and a driven sprocket 4. The work starts from a loading station 5 where it is placed on the conveyor in a horizontal position. Immediately beyond this station, the work is moved to a vertical position and through a temperature equalizing furnace 6. As the work leaves the furnace, it is moved to or below a horizontal position into a quench tank 7. From the quench tank, the work is returned to its Vertical position and moved in sequence, while in this position, through a tempering furnace 8, an air cooling station 9 that is supplied with air by a blower 11 and a Water cooling station 12. Thereafter, the cooled work is removed from the conveyor onto a platform at a discharge station 13.

The conveyor is best shown in Figures 2, 4 and 5. It will be seen that the conveyor includes a roller chain 14 that passes around the sprockets 2, 3 and 4. This chain is connected by brackets 15 with a numberof carriages 16 that ride along a track formed of angle-irons 17. The track is above and parallel to the path through which the chain is moved. Each carriage is identical and is provided with four rollers 18 that are mounted in pairs on the ends of shafts 19 which in turn are journaled in the carriage. Extending downwardly and to one side of the "carriage is a supporting member 21 that has a shaft 22 therethrough parallel to the direction of movement .of the carriage and the conveyor chain. A U-shaped work supporting bracket 23 is pivoted on each end of shaft 22, so that each carriage has two brackets. Each bracket is provided with a projection 24 extending outwardly from its lower corner for a purpose to be described below, while the upper portion of each bracket is formed as a socket which has fastened in it a work supporting rod 25. Surrounding the rod 25 and loosely mounted thereon is a roller or collar 26.

The brackets are normally held in the vertical position shown in Figures 2 and 5 which position is accurately adjusted by means of engagement between a projection 27 on the bracket and the end of a bolt 28 that is threaded into a socket 29 on the carriage. It will, therefore, be seen that as the chain is moved by the sprocket 4, the carriages will ride along track 17 and carry with them the work supporting members 23. These members may be moved around the pivots 22 relative to the carriages to various positions depending upon the location of a particular carriage in its path of travel.

The conveyor is moved to carry the work past the various stations by rotating sprocket 4 counterclockwise in Figure 1. To this end, the sprocket, as shown in Figures 2 and 3, is keyed to the upper end of a shaft 31 that is journaled for rotation in

bearings

32 and 33. Also keyed to the shaft is a ratchet plate 34 that is rotated intermittently by a pawl 35 on an arm 36 that is pivoted for oscillation around shaft 31. The pawl is kept in engagement with the edge of the ratchet plate by means of an arm 37 extending rearwardly therefrom with the outer end of the arm biased in a counterclockwise direction by means of a spring 38. Arm 36 is oscillated around shaft 31 by a piston rod 39 that is pivoted to the arm and which has a piston on its other end that is received in a double acting cylinder 41. The left end of this cylinder is pivoted to the frame at 42, as is shown in Figure 1. Movement of the arm 36 is limited by

stops

43 and 44.

In operation, air is admitted to the left end of cylinder 41 thereby acting through piston rod 39 to move the arm 36 against stop 44. In this position of the arm, the pawl falls behind one of the teeth on ratchet 34. Air is then admitted to the right end of cylinder 41 to produce movement of arm 36 in a counterclockwise direc tion. This arm acts through pawl 35 to rotate sprocket 4 and thereby index the chain of the conveyor one step. Air is admitted to opposite ends of cylinder 41 in any conventional manner at predetermined intervals of time. The various parts that act on the work holders and the work carried thereby are so located relative to the conveyor that they can act on the work holders during periods of rest or for a predetermined length of time respectively.

As the carriage is moved into the loading position 5. the various work supporting brackets and rods 25 are in a substantially horizontal position as shown in Figure 1 and by one of the holders in Figure 5. The exact position of the work holders is determined by the engagement of collar 26 on the shaft 25 and a rail 45 that follows the path of the conveyor. While the work holders are in their horizontal position, the work, which is in this case shown as being a hot forged shell, is moved from a loading platform 57 to the rods 25. The work holders are then moved from the horizontal position in Figure 5 to the vertical position thereof before being carried along by the conveyor. The work holders are shifted from their horizontal to their vertical position by a lifting mechanism that is mounted on a stand 46 located adjacent to the conveyor and located to engage a work holder in a position it will assume between indexmg movements.

As shown in Figure 5, the lifting mechanism is provided with a lifting bar 47 having a roller 48 on the end thereof which engages the projection 24 of the supporting bracket 23 in front of it. Bar 47 is mounted for parallel movement in a horizontal direction by a pair of links 49 and 51 that are pivoted at their lower ends to the bar and at their upper ends to the frame. The pivot for link 51 is a shaft to which it is attached and which also has an arm 52 attached to it and extending in the opposite direction. The outer end of arm 52 is connected to a piston rod 53 whose other end has a piston on it that is received in cylinder 54. The lower end of the cylinder is mounted at 55 for oscillation around a bracket on stand 46. There is also provided a stop 56 to limit the movement of'ann 47 to the right.

Periodically, while the conveyor is at rest, air is introduced into the upper end of cylinder 54 thereby to produce movement of arm 47 to the left in Figure 5. As this movement continues, roller 48 engages a projection 24 of a work holder in a horizontal position and moves this work holder around shaft 22 as a pivot until the holder or bracket 23 is in its full line position. As the bracket 23 is moved in a clockwise direction, it will reach a point where its center of gravity is to the right of shaft 22 and will then fall into its vertical position. Since the center of gravity of the bracket plus the work mounted on the upper end of shaft 25 is to the right of pivot 22, this bracket will remain in position until such time as it is positively moved in a counterclockwise direction. At times the carriages may have a tendency'to tilt out of tracks 17 as the brackets are being pivoted if the work is heavy. This can be overcome by placing a cover over the tracks at the points where the pivoting of the brackets 23 takes place. The cover can take the form;

of a channel such as the forming the bottom of duct 83 in Figure 6.

After the work supports have been moved into their vertical position, continued travel of the conveyor will move them into the furnace 6. As best shown in Figure 6 of the drawing, this furnace has a narrow entrance 58 which leads into a narrow, elongated furnace chamber 59 that is heated by burners 61 located in the sides thereof. The furnace is constructed in accordance with ordinary furnace practice, and the burners are preferably of the type disclosed in Hess Patent 2,215,079. This is a relatively short furnace and in the application shown is to be used only for evening out the temperature of the various sections of the shell. Beyond the burners, at the exit end of the furnace,.there is provided an arcuate hood 62 having an arcuate portion 63 which, in effect, forms an L-shaped extension to the furnace chamber and through which the work supporting members are moved from their vertical position to a position slightly below the horizontal in order to place the work in a quench tank 7. As explained above, the work holders remain in a vertical position due to their construction. They are moved from this vertical position when they reach the hood portion 62 by means of a lowering mechanism which includes a first portion that moves the holders out of the vertical sufiiciently for them to have a tendency to fall in a counterclockwise direction in Figure 6, and a second portion that controls the lowering of the work holders to place the work in the quench liquid in tank 7.

The first portion of the lowering mechanism includes a pusher 64, the outer end of which is guided by a structural member 65 and the inner end of which is connected to a piston rod 66 having a piston on the end thereof that is received in a cylinder 67. When a work holder or bracket 23 is at a position of rest in which it is aligned with the portion 63 of hood 62, fluid is introduced in the right end of cylinder. 67 to move pusher 64 against the upper portion of work holder and thereby move this holder to the left in Figure 6. At this time, the roller 68 on arm 69 that controls thelowering of the work holder, is in its left or dotted line position, so that it will be engaged by projection 24. Arm 69 is supported for parallel movement by a pair of

links

71 and 72, the latter of which is fastened to a shaft 73 that has an arm 74 also fastened to it and projecting in the opposite direction from link 72. The outer end of the arm 74 is attached to piston rod 75 having a piston on it that is received in cylinder 76 the right end of which is pivoted at 77. After the work holder 23 has been moved to bring projection 24 into engagement with roller 68, fluid will be released from the left end of the cylinder and introduced into the right end thereof at a rate to control the lowering or counterclockwise movement of the holder. This continues until the right end of arm 69 is in engagement with a stop 78. At this time, collar 26 on the work holder is resting on a track 79 extending lengthwise through the quench tank. At the same time, the side of the shell blank will engage a pair 'of rods 81, and its end is moved against a shield 82 as it goes below the horizontal. The shield serves to prevent the work from falling oil? the work holder and also extends lengthwise through the quench tank. It is noted that the carriages 16 are covered by a water cooled duct or chamber 83 for the extent of their travel through the furnace. This is to prevent heat from the furnace being reflected downwardly through the slot in the floor thereof against the conveyor mechanism and also to protect the pivot 22 from the heat.

Continued indexing movement of the conveyor moves the. various work holders and the work carried thereby through the quench tank until they reach a position in front of a lifting mechanism 84 that is similar to the mechanism 68 to 78 inclusive but is intended to operate in the opposite fashion. Mechanism 84 serves to return the work holders and the work carried thereby to a vertical position, so that the quenching fluid can drain from the work and the holders. It is noted that this lifting mechanism can be shifted to various points along the quench tank for the purpose of removing the work from the quench liquid after varying periods of time required for the work to be reduced sutficiently in temperature. The more the work is to be cooled in the quench, the further toward the end of the tank 7 mechanism 84 will be located. In any event, this mechanism will be located at least two indexing movements from the end of the tank in order to give the work time to drain before it continues its movement through its path.

After the work holders leave the quench, they pass around sprocket 3 and into reheating or tempering furnace 8 shown in Figure 7. This furnace is constructed similar to the furnace 6 but is longer than furnace 6, since it is used to raise the temperature of the work pieces an appreciable amount. This furnace is constructed in accordance with ordinary furnace practice and is provided with a narrow entrance, shaped to fit the shells, which leads into a narrow elongated furnace chamber 85 that is heated by a plurality of burners 86 located in the side walls thereof. These burners are preferably of the type disclosed in Hess Patent 2,215,079. The work leaves the furnace through a narrow exit 87. It is noted that this furnace, as well as furnace 6, is provided with a slot 88 in the bottom thereof through which the work holders 25 project as they move through this portion of the path. It is also noted that the conveyor is covered for the extent of the furnace by means of a water cooled duct 89 which serves to prevent transfer of heat from the slot to the conveying mechanism.

As work leaves the furnace 8, it passes immediately into an air cooling zone 9 which extends for a relatively long distance along the conveyor. This zone consists of a duct 91 through which air is forced by the fan 11, which duct is located, as best shown in Figure 8, on one side of the work. Opposite the duct is a shield 92. Air is blown from the duct through a slot 93 that extends along the lower portion thereof, so that the air is directed over the surface of the work as well as into the cavity formed in the interior thereof.

As the work leaves the air cooling zone, it passes into a water cooling zone 12, best shown in Figure 9. Extending under this zone is a Water tank 94 from which water is pumped by a pump 95 through a pipe 06 to a plurality of spray nozzles 97 on one side of the conveyor and 8 on the opposite side thereof. Water is sprayed over the work as it passes through this zone in order to cool the work down to handling temperature.

There is provided a shield around the work pieces while they are in this zone to prevent the spray from getting on the surroundings. To this end, there are provided

side pieces

99 and 101 on each side of the spray and end pieces 102, the latter of which are provided with openings through which the work can pass. Water striking against the shields flows downwardly to a collecting pan 103 and from this pan to the tank 94. A shield is provided to insure that water flowing from the pan will go into the tank. If it is found to be desirable, some suitable form of liquid level control can be used to control the level of the liquid in tank 94 and to control the replacement of water that is lost by evaporation or otherwise.

After the work leaves the water cooling zone, it is moved to a position in front of an unloading platform 105 which is shown herein as comprised of a plurality of rollers down which the work can move by gravity when the work carriers are lowered to a position slightly below the horizontal as shown in Figure 10. At this station, there is provided a mechanism to move the work carriers from their vertical position to their lowered position which is determined by an extension of the rail 45. This lowering mechanism includes a plunger 106 to move the work support in a clockwise direction until the projection 24 thereof can be engaged by a further lowering mechanism 107. The lowering mechanism shown in Figure 10 operates in the same manner as that described above in connection with Figure 6 to lower the work into the quench tank. It is noted that the various mechanisms used to raise and to lower the work supports are similar to each other and operate in the same fashion. Those shown in Figure 10 and Figure 5 have the actuating piston disposed vertically and those shown in Figure 6 and at the end ofthe quench tank have the actuating piston disposed horizontally. This change in the position of the piston is necessitated by the space limitations of the apparatus.

' After the work holders pass beyond the unloading station 13, they stay in their horizontal position as they move around sprocket 2 to the loading station. Track 4-5 gradually moves these work holders from the lower than horizontal position shown in Figure 10 to the substantially horizontal position shown in Figure 5 where the operations are repeated for a new cycle.

The operation of the apparatus should be apparent from the above description. A short summary, however, will be given.

If the work is already hot, such as work moving directly from a forge, it will be placed on the work holders at the last station on the loading platform 57 shown in Figure 1. Work at this station will be in the neighborhood of 1550 F. The work will then be moved to its vertical position and carried immediately into the furnace 6 where its temperature will be balanced throughout its entire section and will be raised perhaps or so. Immediately thereafter, the work is moved into the quench tank which will reduce its temperature to a range between 200 F., and 300 F. After the work is quenched, it will be tempered by the furnace 8 which brings its temperature to approximately 1200 F., or slightly below the critical temperature. This reheated work is cooled by the air flowing from duct 91 to about 600 F., and is spray cooled in station 12 to approximately F., at which temperature it can be readily handled by an operator. The various heating and cooling devices are of such a length and are maintained at such a temperature that the temperature of the work pieces is changed the required amount during the time required for them to move through the respective devices. The operations are entirely automatic, since the various lowering and raising mechanisms are to be operated periodically in synchronism with the operation of ratcheting mechanism that rotates sprocket 4. Such synchronous operation can easily be obtained by those skilled in the art by operating solenoid valves, for example, that are placed in the air inlet lines to the various pistons with these valves being energized and deenergized as the sprocket 4 is stepped around. It will be apparent that the work holders 25 on the ends of the arms 23 can take other forms than the bar shown herein, in order that they may accommodate work pieces of different shapes. It is also apparent that the entrance to the furnaces could be shaped to accommodate work pieces of different shapes.

In the above description, it was assumed that the work pieces placed on the work holders at loading platform 57 were already heated to a certain degree. It will be apparent, however, that cold pieces could be placed on the holders at this point if it was so desired. In such event, furnace 6 would have to be made long enough to raise these pieces to the desired temperature.

While in accordance with the provisions of the statutes, we have illustrated and described the best form of embodiment of our invention now known to us it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit and scope of the invention as set forth in the appended claims, and that in some cases certain features of our invention may be used to 7 advantage without a corresponding use of other features What is claimed is:

1. In apparatus for operating successively upon a plurality of articles, the combination of a conveyor movable through a closed horizontal path, a plurality of article supporting members carried by said conveyor, means to mount each of said members on said conveyor for pivotal movement relative thereto from a normal substantially vertical position to a second position at an angle to the vertical, said mounting means including a pivot and means to hold said members on opposite sides of a vertical plane extending through said pivot when in their respective vertical positions and second positions whereby said members will stay in either position when moved thereto, mechanism located adjacent to said path including means to move said members out of the vertical position and means to control movement of said members to said second position, means extending adjacent to said path and engaged by said members to determine said second position, additional mechanism located adjacent to said path to move said members from said second position to the vertical position, and means to operate on articles carried by said members in both positions thereof.

2. In a heat treating apparatus, the combination of a conveyor including a plurality of carriages moving through a closed horizontal path, a plurality of work supports, means to mount one of said supports on each carriage for movement relative thereto from a normal vertical position to a second position below the horizontal, said mounting means including a pivot on each carriage around which a support moves, said pivot being so arranged relative to each carriage and support on said carriages that said supports will remain in either position when moved thereto, a plurality of heat treating work stations located at spaced points along said conveyor, some of said stations receiving said supports in a vertical position and other of said stations receiving said supports in their second positions, means located in front of said stations to move said supports on said carriages to the position 'in which they are received by the station they are approaching, and means to actuate said last mentioned means.

3. In heat treating apparatus, the combination of work advancing means movable through a path, a first heating means located at one point above said path, a quench tank located beyond said first heating means and below said path, a second heating means located beyond said quench tank above said path, carriages attached to said advancing means and carried thereby through said path,

a work holder pivoted to each carriage, means located at a point in front of said first heating means to move the work holders around the pivots on said carriages into a position above said path to enter said first heating means,

means located adjacent to said path between said first heating means and said tank to move the work holders around the pivots on said carriages to a position below said path in which they are immersed in said tank, and means located adjacent to said path and located adjacent to the end of said tank to move said work holders around the pivots on said carriages out of said tank and into a position above said path to enter said second heating means.

4. In heat treating apparatus, the combination of a conveyor traveling in a closed horizontal path, a quench tank located beneath a portion of said path, a plurality of carriages attached to and traveling with said conveyor, a work holder extending normally in a vertical direction, a horizontal pivot by means of which a work holder is pivoted to each carriage, mechanism located beside said conveyor adjacent to the entrance end of said quench tank including as a part thereof means to move said work holders in a vertical plane around their pivots from their normal position to a position below said conveyer in which articles carried thereby will be immersed in said tank, means in said tank to maintain the articles on said work holders, means also in said tank to limit the movement of the work holders around their pivots on said carriages, and mechanism located beside said path adjacent to the exit end of said quench tank to movesaid work holders back to their normal vertical position.

5. In apparatus for heat treating metal, the combination of means to move a plurality of work pieces through a path including a chain, means to advance said chain, tracks located adjacent and parallel to said path, a plurality of carriages movable along said tracks, means to connect said carriages at spaced points to said chain to be moved thereby, work holding members pivoted to said carriages, said members having a normal predetermined position With respect to said carriages,'means located at a predetermined point along said path to move said work holders out of said normal position to a second position, additional means located at another predetermined point along said path to move said work holders back into said normal position and a cover extending over a portion of said track and the carriages thereon, the pivots between said carriages and the work holders being below and to one side of said tracks, said work holders being so shaped that they extend upwardly from said pivots and inwardly above the cover over said carriages.

6. The combination of claim 5 in which the normal position of said work holders is vertical, and in which said second position of said work holders is substantially horizontal whereby to facilitate the loading and unloading of work pieces thereon, and mechanism to perform work on the work pieces on said work holders as they are traveling between said two moving means.

7. In heat treating apparatus, the combination of an endless conveyer moving through a fixed path, means to advance said conveyer through said path in a sequence of steps, a plurality of workholders, means to mount said holders at spaced points on said conveyer for pivoted movement in a plane substantially perpendicular to the direction of conveyer travel from a vertical position through a dead center position to a substantially horizontal position, the weight of said holder maintaining it in its vertical or horizontal position, a plurality of heat treating devices located along said path and adapted to treat work carried by said holders in their vertical and their horizontal positions, and means located adjacent to said conveyer at points in advance to said devices operative to move said holders to the position in which work thereon can be treated.

8. The combination of claim'7 in which said moving means is located to move said workholders when they are at rest between the step movements of said conveyer.

9. In heat treating apparatus, the combination of a track extending through a path, a plurality of carriages on said track, each carriage having a portion extending below and toward one side of said track, a work carrier pivoted to said portion and being so formed that it extends around said track to a position above said carriage toward the other side thereof, the weight of said carrier holding it in that position with a part thereof extending vertically, means located on the opposite side of said track from that toward which said portion extends operative to move said carrier out of its vertical position, to an extent where it can fall around its pivot, means to control the downward movement of said carrier, and means to limit said movement.

10. The combination of claim 9 including means to return said carrier to a position in which said part is vertical, said means being located beside said track and beyond said first means in the direction of movement of said carriage along said track.

11. In a heat treating machine, a heat treating device, a pair of rails extending through a path past said device, a carriage movable on said tracks, a workholder,

means to mount said holder on said carriage for movement in a direction substantially perpendicular to said path from a normal vertical position through a dead center position to a position substantially horizontal, cooperating means on said holder and carriage to determine exactly said vertical position, means located beside said track to move said holder from its vertical position through its dead center position whereby it can fall to its horizontal position, means to control the movement of said holder as it is falling, means to determine said horizontal position, and additional means located along said path beyond said first means to move said holder from its horizontal position through its dead center position whereby it can fall to its vertical position.

12. The combination of claim 11 including means to hold Work on said work holder when it is in its horizontal position.

13. Heat treating apparatus comprising in combination a conveyer traveling through a closed horizontal path, a first heat treating device above and aligned with said conveyer, a second heat treating device below and to one side of said conveyer, a carriage on said conveyer, a workholder having a portion normally extending vertically above said carriage and a portion off-set to one side thereof, means to pivot said ofi-set portion of said workholder to said carriage at a point adjacent to one side thereof and for movement in a plane perpendicular to the path of carriage travel, adjustable means between said carriage and ofi-set portion to determine the normal position of said vertical portion, means operative to engage said vertical portion and move said workholder around said pivot so that it may extend to the side of said conveyor on which said second device is located, means to align said workholder to travel through said 10 second device as said carriage moves with said conveyer, and means located beside said conveyer to return said workholder around said pivot to its normal vertical position aligned with said first device.

14. Heat treating apparatus comprising in combination a conveyer moving through a horizontal path, first and second heating devices located at spaced points along said path and vertically above said conveyer, a quenching device located along said path between said devices and to one side of said conveyer, a carriage on said conveyer having a part projecting toward said side, a workholder on said carriage having a vertical portion centered with respect thereto and a portion ofi-set toward said side, means to pivot said ofi-set portion to said part of said carriage whereby said holder can move on said carriage from a vertical position aligned with said heating devices to a position to the side of said conveyer aligned with said quenching device, means to locate accurately said holder in said positions, means located along said path ahead of said quench device to move said holder from its vertical position to its position aligned with said quench device, and means located along said path ahead of said heating devices to move said holder into its vertical position aligned with said heating devices.

References Cited in the file of this patent UNITED STATES PATENTS 383,030 White May 15, 1888 1,783,155 Talley Nov. 25, 1930 2,322,777 Purnell June 29, 1943 2,393,521 Duncan et al. Ian. 22, 1946 2,504,815 Detuno Apr. 18, 1950 2,548,683 Remington et al. Apr. 10, 1951 2,642,212 Currivan June 16, 1953