US 2678559 A
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M y 18, 1954 H. c. DRAKE 2,678,559
ULTRASONIC RAIL TEST DEVICE Filed Dec. 29, 1951 FIG. I
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I, INVENTOR. R HARCOURT c. DRAKE ATTORNEY Patented May 18, 1954 ULTRASONIC RAIL TEST DEVICE Harcourt C. Drake, Hempstead, N. Y., assignor to Sperry Products, Inc., Danbury, Conn., a corporation of New York Application December 29, 1951, Serial No. 264,145
This invention relates to the testing of rails in track by ultrasonic vibrations. Such vibrations are generated by an electro-acoustic transducer in the form of a piezo-electric quartz crystal which is electrically energized at high frequency and which converts the electric oscillations into mechanical oscillations. The quartz crystal is mounted on a suitable support which engages the rail through a couplant, such as oil, and is moved continuously along the rails. This movement, however, creates a problem because the rail lengths are joined together by joints which allow considerable vertical play. As a result, there is frequently met the condition where the receiving end of the succeeding rail is higher than the end of the leaving rail, causing the crystal support to strike heavily. At best this causes rapid wear of the support, and under the worst conditions can cause upsetting and destruction of the entire search unit.
It is the principal object of this invention, therefore, to provide means for preventing excessiv wear of the support and possible upsetting of the search unit because of higher receiving ends on succeeding rails.
Further objects and advantages of this invention will become apparent in the following detailed description thereof.
In the accompanying drawings,
Fig. 1 is a side elevation of a search unit applied to a rail, and shows the theory underlying the invention.
Fig. 2 is a side elevation of a car and search unit, with means for remedying the condition shown in Fig. l. a
Fig. 3 is a View similar to Fig. 2, showing a modified form of the invention.
Referring to Fig. 1, there is shown a portion of on rail of a track. Such rail consists of a plurality of rail lengths R, R joined together at their ends by a joint which comprises a joint bar J, bolt B extending through bolt holes, and other elements not shown. There is possibility of vertical misalignment of the rail ends, particularly under stress of heavy loads, and a condition is frequently met where the next or succeeding rail R has its receiving end slightly higher than the leaving end of rail R, as shown in Fig. 1.
Such a condition as described above is highly undesirable in testing rail in track by ultrasonic vibrations. In this method of testing, a quartz crystal Ill is mounted on a support I i. The support is usually of plastic material, and a couplant such as oil is interposed between the support and the rail to facilitate transmission of vibrations into the rail. The crystal and its support constitute a search unit which may be suspended from a carriage l 5 by means such as a link 16 pivoted at ll to the carriage and at IE to the search unit. The carriage is adapted to ride upon the rail surface by means such as wheels [9 and is supported on a beam 2!] by means of bolts 2| fixed to carriage l5 and extending loosely through openings 22 to permit the carriage to adjust itself to the contour of the rail surface. Springs 23 normally press the carriage toward engagement with the rail, while springs 24 interposed between the carriage and the search unit press the latter toward engagement with the rail. The beam 2!! may be pivoted on the front of a car 21 at 28 and can be raised and lowered by means of cable 25 and pulley 26 on the car.
In the above arrangement it will be apparent that when the condiiton shown in Fig. 1 is encountered, and the search unit is travelling in the direction of the arrow, excessive wear and damage to the search unit can result from striking the raised receiving end of rail R. Therefore to insure that no such projection is encountered in the path of the moving search unit, I take advantage of the fact that there is a certain amount of play between the joint bars and the rails joined thereby. Such being the case, I provide just ahead of the carriage I5 a heavily weighted wheel 30 which will engage the receivin end of each rail just ahead of the search unit and depress the receiving end to a point at least flush with the leaving end of the preceding rail, and in some cases even slightly below such leaving end. The weight is applied to the rail in sufficiently close proximity to the search unit to give said unit the full advantage of the rail depressing effect of the weight on the rail. This will insure unopposed sliding movement of the search unit from one rail to the next.
In a modified form of the invention, shown in Fig. 3, where it is possible to mount the search unit on the rear of the car, the entire carriage l5 may be supported from a rearward extension 32 on the car 21, sufficiently close to the rear wheel 35 so as to take advantage of the weight of the car in depressing the receiving end of rail R.
Having described my invention, what I claim and desire to secure by Letters Patent is:
1. An ultrasonic rail testing device comprising a car adapted to travel along the rails, the leaving end of each rail being joined to the receiving end of the succeeding rail, an ultrasonic search unit carried by the car and comprising an electroacoustic transducer and a support for said transducer adapted to slide along the rail, and means for preventing engagement of said support with the upwardly projecting receiving ends of the rails, said last-named means comprising a weight carried by the car in engagement with the rail and sufiicient to depress the rail end, and means for mounting said Weight in advance of said search unit.
2. An ultrasonic rail testing device comprising a car adapted to travel along the rails, the leaving end of each rail being joined to the receiving end of the succeeding rail, an ultrasonic search unit carried by the car and comprising an electroacoustic transducer and a support for said transducer adapted to slide along the rail, and means for preventing engagement of said support with the upwardly projecting receiving ends of the rails, said last-named means comprisin a weight carried by the car in engagement with the rail and sufficient to depress the rail end, and means for mounting said weight in advance of said search unit and in sufiiciently close proximity to give the search unit the full advantage of the rail depressing efiect of the weight on the receiving end of the rail.
References Cited in the file Of this patent UNITED STATES PATENTS Number Name Date 2,276,011 Billstein Mar. 10, 1942 2,527,986 Carlin Oct. 31, 1950