US2263621A - Rail quenching apparatus and method - Google Patents

Description

Nov. 25, 1941. R. E. FRICKEY RAIL UENbHINe APPARATUS AND METHOD 6 Sheets-Sheet 1 Filed Jan. 10, 1939 INVENTOR. Faga/ E. Fr/cvgg WWW/4% ATTORNEY NOV. 25, 1941. c E 2,263,621

RAIL QUENCHING APPARATUS AND METHOD Filed Jan. 10, 1939 6 Sheets-Sheet 2 mmvma fogs'l/ Z. Fr/kkez M2 HEEL.

A TTORNEY 111:. El, h H,

6 Sheets-Sheet 5 m mHlmP INVHVTOR. Paga/ f. Fr/fc'keg ATTORNEY Nov. 25, 1941. R. E. FRICKEY RAIL QUENCHING' APPARATUS AND METHOD Filed Jan. 10, 1933 Nov. 25, 1941, R. E. FRICKEY RAIL QUENGHING APPARATUS AND METHOD Filed Jan. 10, 1939 l 6 Sheets-Sheet 4 INVENTOR. Royal .5. Fr/cL eg ATTORNEY BY Q Q m m-HKP F Nbv. 25, 1941. R. E; FRICKEY 2,263,621

RAIL QUENCHING APPARATUS AND METHOD Filed Jan. 10, 1939 6,Sheets-Sheet 5 INVENTOR. Foga/ 1.. 'Fr/c'eg BY 419? g ATTORNEY Nov. 25, 1941. RE. FRICKEY RAIL UENCH NG' APPARATUS AND METHOD Filed Jan. 10, 1939 6 Sheets-Sheet 6 INVEN TOR. Paga/ Fr/cA eg A TTORNEY Patented Nov. 25,1941

Royal E. Frickey, San Francisco, Galif., assignor to Welding Service, Inc., San Francisco, Calif.,

a corporation of California Application January 10, 1939, Serial No. 250,108.

(01. ace-6) 12 Claims.

This invention relates generally to the construction of quenching apparatus for the hardening of railroad rails. It also relates to methods for hardening the ends of railroad rails by a chilling or quenching operation.

In Frickey and Kalenborn Patents Nos. 2,070,- B89 and 2,013,461, there is disclosed an apparatus and method for the hardening of railroad rail ends, involving a rapid heating of the end of quenching apparatus in accordance with. the present invention.

Fig. 2 is a cross-sectional detail taken along the lines 2-2 of Fig. 3 and showing means for V adjusting the timing.

Fig. 3 is a plan view ofthe timing means illustrated in Fig. 2.

Fig. 4 is a cross-sectional view taken along the line 4-4 of Fig. 1.

the rail followed by application of a liquid chillin Fi 5 is a cross-sect o al ew a n along the ing medium. Also in my Patent No. 2,103,716 there is disclosed an improved method involving the use of a high frequency electromagnetic field, for controlled heating of the upper surface of the rail ball at the end of the rail.

The chilling apparatus disclosed in said Patents 2,070,889 and 2,013,461 makes use of an open bottomed box into which a chilling liquid like oil is introduced. Such chilling apparatus has been successfully used in field operations on rails which ave been laid. Where it is desired to carry out hardening operations at the mill, by use of a chilling medium, the open bottomed box type chilling equipment, such as disclosed in said Patents Nos. 2,070,889 and 2,013,461 is subject to certain disadvantages. It is not susceptibleto such accurate control of the hardnes pattern as is frequently desired,or as is possible with the present invention. Furthermore the use of a box involves the problem of making a seal with the rail, and the use of gaskets for this purpose is troublesome and may interfere with the desired hardness pattern. 1

It is an object of the present invention to;

provid a quenching apparatus and method ca: pable of precise control of the hardness pattern, and which can make use of an inexpensive chilling medium such as water. I

Another object of the invention is to provide a quenching apparatus and method capable .of

relatively rapid operation whereby it can be used successfully for commercial hardening of rail ends at the mill.

A further object of the invention is to provide a substantially automatic form of quenching apparatus which will give uniform results in successive operations without careful supervision by an operator.

Additional objects of the invention will ap-i pear from the following description in which the preferred embodiment has been set forth in detail in conjunction with the accompanying drawings. a

Referring to the drawings:

Fig. 10 is a cross-sectional view taken along the line I0l 0 of Fig. 9.

Fig. 11 is a bottom plan View of the machine.

Fig. 12 is an enlarged cross-sectional detail, showing one of the side assemblies for engagement with the side of the rail balls.

Fig. 13 is an enlarged cross-sectional detail taken along the line l3--| 3 of Fig. 6.

Fig. 14 is a diagrammatic view for the p p of illustrating cyclic-movement of the nozzle relative to the rail.

Fig. 15 is a circuit diagram illustrating electrical connections to the equipment.

The present apparatus makes use of a nozzle from which water or like chilling liquid is jetted. The jet of chilling liquid is directed from above the upper heated surface of the rail, wherebythe liquid immediately contacts with the rail and then flows as a uniform stream to its point of removal. Mechanism driven by a motor serves to move the nozzle cyclically to obtain a predetermined hardness pattern.

To describe the machine as illustrated in the drawings, it consists of a suitable'frame-work I made of suitable structural members, the lower part of which carries means for seating upon the upper surface. of a rail ball. Thus at the lower end of the frame (Figs. 1, 4 and 5) .there is "a base II which can be formed as a suitable metal casting. The lateral members l2 and I3 (Fig. 11) form a part of this base, and are pro- Fig. 1 is a side elevational view illustrating chine upon a rail, and to assist in guiding the apparatus to proper position, two pair of guide members l1 and -|8 are provided. The guide members I1 are carried by the slotted arms L! which in turn are adjustably bolted to the fixed lugs 2| of the frame. Guide members I6 are likewise carried byslotted arms 22 which are adjustably bolted to-the frame lugs 23.

Near the forward end of the machine assemblies 26 are provided which are adapted to engage the sides of the rail ball, and. which serve to collect a part of the water discharged from the nozzle. These assemblies are likewise secured to slotted arms I9, which in turn are adjustably bolted tothe base of the machine. Each assembly 26 includes a trough or groove 28, for receiving liquid, a, lip 29 which is adapted to be positioned adjacent the side edge of the rail ball, and a gasket 3| of suitable material such as asbestos fiber, which is adapted to be pressed upon the upper side edges of the rail. Plates 32 establi'sh actual contact with the sides of the rail ball, and serve to retain the gaskets 3| upon the assembly. By removal of the wing nuts 33 the parts of this arrangement can be dis-assembled for the purpose of renewing the gasket 3|.

At thatend of the machine where the assemblies 26 are located, there is also a liquid deflector 34 (Fig. 10). This deflector can be attached 'to the frame of the machine, as shown in Fig. 9, and itserves to direct liquid discharged from the adjacent end of the rail, as well as from the troughs= 28 in the assembly 26, to a convenient sump. Liquid s collected can be returned for re-use.'

Fig. 10 illustrates how the machine is set upon a railroad rail, preparatory for a chilling operaated at a constant but relatively slower speed. For supplying water to the nozzle 38, a hose or pipe connects to a source of liquid of substantially constant temperature and pressure.

tion. The. guides 11 and I8 are in close proximity to the sides of the rail, and the end of the rail which has previously been heated preparatory to the quenching operation, occupies a position between the assemblies 26.

Positioned to overlie the upper surface of the rail, there is a nozzle 36 for the discharge of chilling liquid, such as water. The tip 31 is inclined downwardly towards the surface of the rail, and affords an elongated or substantially flat orifice 38, which is substantially greater than one-half the width of the rail ball. The tip 31 of the nozzle is disposed at such an angle to the upper surface of the rail, that the jet is discharged downwardlyand longitudinally of the rail, as for example at an angle of about 15.

The means for supporting and imparting motion to the nozzle 36, includes the following:

To the rear of the nozzle 36 there is a sleeve 39,

carried by the lateral member 2 of the base. Rod 46 is slidably disposed within this sleeve. and one end ofthis rod has a ball and socket coupling 4| to the nozzle. This ball and socket coupling enables adjustment of the nozzle 36 to any desired position, after which it may be tightened to retain the nozzle properly adjusted.

The attachment of coupling 4| to the rod 46 includes an adjustable sleeve 42. The other end of rod 46 is provided with a roller 43, adapted to engage the'outer periphery of a cam wheel 44. Rod 48 is always urged in a direction towards cam wheel 44, by means of the tension springs 45. Cam wheel 44 is carried by the lower end of a shaft 46, and this shaft extends from-a gear reduction box 41. gear reduction box 41, connects with the electric motor 49, which can be a constant speed synchronous type. Since the electric motor 49 operates at a constant speed, cam wheel 44 is oper- The driven shaft 48 of For example in actual practice I have kept water in a storage tank at a fixed elevation above the machine, with the tank equipped with a thermostatically controlled heater to maintain the water at a predetermined temperature level above atmospheric, as for example a temperature such as 140 F. Pipe 5| connects to a valve 52, which in turn connects to the pipe 53, and hose 54. The hose 54 extends generally upright and has its lower end coupled to the nozzle 36. The valve 52 has a manual operating lever 56, which is in v the position illustrated in Fig. 6, when the valve is closed. A spring 55 serves to urge lever 56 toward closed position. By movement of hand lever 56 to the right as viewed in Fig. 6, the valve can be opened to deliver water to the nozzle 36.

In conjunction with the handle 56 of valve 52, there is a magnetic holding device 51 (Figs. 4 and 13). The rock shaft 58 of device 51 carries a yoke-like arm 59, which is connected by link 6|, to the lever 62. Lever 62 is attached to the same shaft 63, as the operating handle 56. Deenergization of the magnetic device 51 releases lever 56 thus permitting this lever to move to closed position. Yoke-like arm 59 also forms a tilting mounting for a pair of mercury tubes 64 and 65. These tubes form contact devices for a purpose to be presently explained.

In order to carry out the quenching operation automatically and over a predetermined period of time, means are provided for automatically energizing the motor 49 when the valve handle 56 is moved to open position, and also for automatically de-energizing this motor when the nozzle has completed a cycle of movement. In addition, timing means is provided for de-en'ergizing the magnetic device 51 to effect automatic closure of valve 52. Referring first to Fig. 5, the shaft 46 which serves as a mounting for the cam wheel 44, is extended upwardly beyond the housing of the gear box 41, where it carries the cam wheels 61, 68 and 69 (Figs. 1, 2, 3 and 5). These cam wheels operate contacts 1|, 12 and 13 respectively. Each of the cam wheels 61 and 68 has a circular periphery except for the provision of a notch 16, which serves to permit contacts 1| and 12 to open. In other words for substantially 360 rotation of the cams 61 and 68, the contacts 1| and 12 remain closed, but for a minor part of the angular movement, as for example 10 or |5, contacts 1| and 12 are open. Cam wheel 69 also has a notch 11, which functions in the same manner with-respect to contacts 13 (see Fig. 3).

In order to adjust the time period of the quench, I provide means for limited angular adjustment of cam 69 with respect to shaft 46. Thus as shown in Fig. 2 the cam wheel 69 is mounted for rotation relative to shaft 46, and

secured to this cam wheel there is a worm gear 19. Secured to the adjacent part of the shaft 46 there is an arm 8|, and journalled to this arm there is an adjusting shaft 82. Shaft 82 carries a worm 83, engaging the teeth of worm gear 19. Thus rotation of wormgear 83 enables accurate angular adjustment of the cam wheel 69, relative to the shaft 46. One can therefore adjust the precise point in the rotation of shaft conductor 96 leads directly to the motor.

- ience in handling the apparatus, tubular, handles 81 may be mounted along the sides of the frame.

Referring back to the main cam wheel 44, particularly as illustrated diagrammatically in Fig. 15, its cam surface may be divided into a plurality of portions a, b. c and d. Before describing operation of the machine as a whole, it can be pointed out that the starting point for cam 44, at the commencement of a' cycle of operation is as shown in Fig. 15. When. the driving motor 49 is energized at the commencement of the cycle, the cam wheel 44 rotates'clockwise as viewed in Fig. 15, and therefore cam wheel 43 moves rapidly down th cam surface a. This serves to cause movement of the nozzle 36 from a point adjacent the tip of the rail, to a point a suitable distance back from the end of the rail, as for example in the neighborhood of 4 to 4 inches. Fig. 9 illustrates the position of cam roller 43 immediately after full retraction of the nozzle. Continued rotation of cam wheel 44 at a constant rate causes cam roller 43 to ride upon the surface b, until the roller .43 engages the surface 0. Riding of the roller upon surface b causes the nozzle to be again advanced towards the end of the rail to a point which is still spaced from the end of the rail by a suitable distance, as for example from 1 to 1 inches. The nozzle now remains in this position while the roller 43 rides upon the surface 0, and until the roller engages the surface (1. Engagement with surface 11 causes the nozzle 36 to be again projected to a point at the tip of the rail, corresponding to the starting point. As will be presently explained the motor is de-energized and. cam wheel 44 stopped when it has completed one revoluand g4 connect the contacts of mercury switch 65 directlyin shunt with the contacts 12. Contacts 13 together with the winding of magnetic device 'l-are connected in series and across a direct current supply source 95. Hand lever 56, valve 52, lever and link 62 and 6|, are diagrammatic representations of the corresponding parts previously described. The motor 49 is of the three-phas synchronous type, supplied from the alternating current lines Ll, L2 and L3. One An-- other conductor 91 .from the motor connects to 'one side of the contacts I I, and the other side of these contacts is connected by conductor 98 to the current supply line L3. Another conductor 99 from. the motor connects to one side of the .contact 12, and the other side of these contacts connects by conductor IOI to the current supply line LI It will be apparent that when either the mercury switches 64 and 65, or the contacts H or 12, are closed, the motor 49 is energized.

The positioning of- thecams 61, 68 and 69, and also the main cam wheel 44, illustrated in Fig. 15; conforms substantially to the position- .shaft 46 has rotated a predetermined amount,

ing of these parts before a cycle of operation is initiated. It'will be noted that contacts 13 are closed whereby magnetic device 51 is energized,

'andcontacts H and 12 are opened, because of the positioning of the cam recesses 16 of cams 61- and 68. Energizing of magnetic device 51 is not suflicient to move the valve 52 to open position. To initiate a cycle of operation, the operator swings the handle 56 to open the valve 52, and this movement causes a tipping of mercury switches 643 and 65, to close the contacts of the same. Since the contacts of these mercury switches are in shunt with contacts H and 12, the motor 49 is thereby energized to commence rotation of the main cam 44. After the depending upon the setting of the cam. 69, recess 11 comes in such position as to cause opening of contact 13, with the result that the magnetic device 51 is de-energized for a short interval. It may be pointed out that before de-energizing device 51, it exerts sufiicient force to retain the handle 56 in on position, against the tension spring 55. However, upon de-energization as described, the handle 56 swings back to closed or off position to close valve 52. Swinging of handle 56 back to closed position of valve 52, is

closed, thereby causing the supply of current to.

the motor to be cdntinued. Shaft 46 therefore continuously rotates until cam recesses 16 move back to the position illustrated in Fig. 15, 150 cause opening of contacts TI and I2. The motor then ceases to operate, and the shaft 46 comes to rest.

Operation of the apparatus as a whole should be apparent from the foregoing, but can be briefly reviewed as follows: With the motor 49 de-energized and the parts substantially in the position illustrated in Fig. 15,the operator takes the complete apparatus and seats it.upon the end of a railroad rail, which is to be quenched. Because of the weight of the apparatus it is desirable to employ suitable suspension means such as a supporting cable and counterbalance. The positioning of the device upon the rail willbe substantially as illustrated in Fig. 10. Care should be taken to have the upper surface of the rail horizontal.

The heating operation employed before the apparatus is seated upon the rail, should be such as to heat an upper layer of the rail ball,

near the end of the rail, to a temperature above its critical value. The heating means employed should be capable of accurate control so that the amount of heat applied, the pattern of the heat, and the temperatures attained at different points in the heated layer, are the same for successive the rail ball, and relatively close to the tip of the rail. Fig. 14 illustrates several different positions of the nozzle 36. The right-hand position illustrated corresponds substantially to what may be the initial position of the nozzle, as the apparatus is seated upon the rail. In this instance the tip of the nozzle is approximately /2 inch from the rail end. The operator now throws the handle to on position, which results in simultane-.

ous energization of motor 49, and the discharge of a stream of water from the nozzle 36. This stream of waterstrikes the upper face of the rafl at an angle as previously described, whereby the discharged water flushes forwardly over the heated surface. Due to rotation of the main cam the nozzle 36 immediately commences to retract from the end of the rail, and the rate of retraction is such that it is completely retracted in a minor fraction of the complete quenching period,

v as for example in 4 /2 seconds for a total quenching period of 30 seconds. Immediately after full retraction which is represented by the left-hand position of nozzle 30, in Fig. 14, the nozzle is advanced to the intermediate position as illustrated in Fig. 14, after which it is held stationary, until the end ofrthe operating cycle. As an example of suitable practice the advance to intermediate position may be carried out in about 3 /2 seconds for a total chilling period of 30 seconds. At all times, irrespective of the position of the nozzle, suflicient water in the form of a fiat jet is discharged from the nozzle to flush completely over all of the area of the upper surface of the rail between the nozzle and the tip of the rail. In other words at all times there is some water being discharged over the tip of the rail. Some excess water discharges laterally into the troughs of the assemblies 26, and because of the gaskets 3| no water is permitted to flow down the sides of the rail ball. In other words'there is complete blanketing of the exposed surface of the heated rail for that area between the tip of the rail and the nozzle.

, As a result of the cyclic movement of the nozzle during a chilling operation, I produce a pre determined hardness pattern involving in general the production of a hardness of an optimum value for a short distance of about 1 to 1 /2 inches back from the tip of the rail, with the hardness from that point gradually decreasing to the value of the untreated rail metal, at a region in the neighborhood of 3 inches from the end of the rail.

These figures are to be taken as general, since it will be evident that the length of the hardened area may vary between reasonable limits, and may vary with different size rails. It will be understood from the foregoing that with the cycle of movement described for nozzle 36, the longest chilling period is for a short area near the tip of the rail, where the greatest hardness is desired.

During the initial retraction of the nozzle for portion a of the cam, the metal over the entire heated area is quenched below its critical temperature. For the remainder of the chilling cycle heat is withdrawn in such a manner as to secure a controlled drawing or tempering of the metal.

7 After the chilling operation some further drawing occurs because of heat remaining in the rail below the chilled area. In this connection I prefer to blanket the end of the rail immediately after the chilling operation, as for example by the use of suitable heat insulating box. During such further drawing there is a re-distribution of residual heat, and the upper layer of metal near the end of the rail is tempered to the desired hardness. As an example of typical practice, at the completion of the hardening operation the metal near the end of the rail can have a hardness of about 400 Brinell, and the hardness of the remainder of the hardened area can fall off gradually from about 400 Brinell to about 260 .also exercised of the hardness pattern laterally of the rail ball. The gaskets 3i insulate the upper edges of the rail ball from the flowing stream of water, and therefore these edges are not hardened to the same degree as the upper layer of metal immediately underlying the stream of liquid. If desired the width of the gaskets 3| can be adjusted in order to narrow or widen the width of the hardened area, with respect to the total width of the rail ball.

It will be evident from the foregoing that the apparatus and method constituting the present invention, makes possible the hardening of rail ends to a high degree of accuracy, with a predetermined optimum hardness pattern. The invention is well adapted for use at steel mills, for

the hardening of rail ends in large quantities,-

before the rails are shipped to be laid. An optimum degree of hardness is attained directly at the tip of the rail, where the rail is customarily subjected to the pounding of rolling stock. The hardness can be confined to the top of the rail ball with no undue hardness along the upper edges of the ball, such as might cause an uneven wearing away of the inner surface of the rail. The quenching cycle is controlled automatically, and therefore an operator can secure precise results for a great number of successive operations, it being only necessary to apply the apparatus at a proper time to the rail, following a proper heating operation.

I claim:

1. In a method for the hardening of heated rail surfaces, the step of flushing a chilling liquid over the heated surface of the rail, and causing the area of the heated surface in contact with the liquid to vary over the chilling period for producing a predetermined hardness pattern.

2. In a method for the hardening of heated rail ends by use of a nozzle from which a chilling liquid can be jetted, the step of causing the chilling liquid jetting from said nozzle to flush over the heated surface of the rail, and causing the nozzle to move relative to the rail to vary the area of the heated surface in contact with the liquid and thereby produce a predetermined hardness pattern. 7

3. In a method for the hardening of heated rail ends characterized by use of a nozzle from which a chilling liquid can be jetted, the step of directing the liquid issuing from said nozzle upon the upper surface of the rail adjacent the rail end whereby the chilling liquid flushes over the upper surface of the rail ball, and causing relative movement between the nozzle and the rail to vary the area of the heated surface in contact with the liquid and thereby produce a predeter- -mined hardness pattern.

'4. In a method for the hardening of heated rail ends, characterized by the use of a nozzle from which a chilling liquid like water can be jetted, the steps of directing the jet of liquid from the nozzle upon the upper surface of the rail ball adjacent the end of the rail, whereby liquid issuing from said nozzle is caused to flush over the upper surface of the rail ball, and moving the nozzle cyclically with respect to the rail, the cycle of movement commencing at a point near the tip of the rail, and proceeding with movement of the nozzle back from the tip of the rail, and then towards the tip of the rail.

5. In a method for the hardening of heated rail ends, characterized by the use of a nozzle from which a chilling liquid like water can be jetted, the steps of directing the jet from said nozzle whereby the liquid is caused to flush over the upper surface of the rail ball, and causing the nozzle to move cyclically in a general direction longitudinally of the rail, said cycle commencing with movement of the nozzle from a point adjacent the tip of the rail backwardly from the tip of the rail, the initial part of such movement being relatively slow and the latter part being more rapid, then causing the nozzle to move in a reverse direction towards the tip of the rail at a. relatively rapid rate, and lastly retaining the nozzle at a point spaced from but adjacent the tip of the rail.

6. In a method for the hardening of'rail ends following a heating operation in which an upper layer of the rail ball near the end of the rail is heated to a temperature above its critical value, contacting the entire heated area with a chilling liquid to rapidly reduce its temperature below its critical value, and then continuing contact of only a portion of the heated area with a chilling medium for a predetermined period of time, said first-named contact being fora period of time which is a minor fraction of the total period of chill.

'7. In a method for the hardening of rail ends following a heating operation in which an upper layer of the rail ball near the end of the rail is heated to a temperature above it's critical value, contacting the entire heated area with a chilling liquid to rapidly reduce its temperature below its critical value, and then continuing contact of only a portion of the heated area with a chilling medium for a predetermined period of time, said first-named contact being fora period of time which is a minor fraction of the total period of chill, said portion being nearest the end of the I rail.

8. In apparatus for the chilling of heated rail ends to effect hardening of the same, a nozzle adapted to jet a chilling liquid upon the upper surface of the rail, means for supporting said nozzle adjacent the upper surface of the rail, and means for cyclically moving the nozzle relative to the rail, said last named means including means for effecting a-dwell in the movement of said nozzle with said nozzle positioned at an intermediate point of the heated rail surface, whereby to subject only a portion of said heated surface to the chilling liquid during said dwell.

9. In apparatus for the hardening of heated rail ends by application of a chilling liquid, a nozzle serving to jet a chilling liquid, means for supporting said nozzle in relatively spaced relationship with the upper surface of the rail ball,

driving motor, means including a cam element and means serving to cyclically move said nozzle parallel to the upper rail surface, said last named means including means for efiecting a dwell in the movement of said nozzle with said nozzle positioned at an intermediate point of the heated rail surface, whereby to subject only a portion of said heated surface to the chilling liquid during said dwell.

10. In apparatus for the hardening of heated moving the nozzle relative to the upper surface of the rail, the operation of said last named means being automatically initiated by opening of said valve, and timing means serving to effect automatic closure of said valve.

11. In apparatus of the character described for effecting hardening of heated rail ends by chilling, a nozzle serving to discharge a chilling liquid upon the heated rail surface, means serving to support said nozzle for movement adjacent to and parallel to the upper surface of the rail, a

for causing said motor to impart cyclic movement to said nozzle, said cyclic movement commencing with the nozzle adjacent the tip of the rail, and involving rapid movement of the nozzle backwardly from the tip of the rail, and then a slower reverse movement of the nozzle back towards the tip of the rail, and means for supplying a chilling liquid at predetermined pressure to said nozzle.

12. In apparatus of the character described for hardening of heated rail ends by chilling, a nozzle for the discharge of a chilling liquid, means serving to mount said nozzle adjacent the upper surface of the rail for movement parallel to the rail, a motor, drive means including a cam element causing the motor to impart cyclic movement to the nozzle, the cycle commencing with the nozzle adjacent the tip of the rail and serving first to retract the nozzle from the tip of the rail and then to reverse movement of the nozzle and to cause the same to again approach the tip of the rail, a source of chilling liquid under pressure connected to said nozzle, valve means adapted to be opened and closed for controlling supply of liquid to the nozzle, means serving to initiate said cycle of movement upon opening of said valve, and timing means serving to automatically close said valve after a predetermined p riod of time after commencement of said cycle.

ROYAL E. FRICKEY.

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