US1423466A - Interlocking blade shroud - Google Patents

Description

tears JOI-IN EDWIN SNYDER, 0F PHILADELPHIA, PENNSYLVANIA, ASSIGNOR T0 IESTING- HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CRPORATION OF PENN-` SYLVANIA.

INTERLOCKING BLADE SHROUD.

Mesaee.

Specification of Letters Patent.

llatenteol July i8, 3.922.

To f/,Z whom t may concer/n.:

Be it known that I, IOHN ll'nwiN iiivrnnn, a citizen of the Uni ted States, and a resident of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented a new and useful Improvement ia Interlocking Blade Shrouds, of which the following is a specification.

This invention relates to blade shrouds such as are employed in turbines for looking together and shrouding the outer ends of blades, and particularly as employed in connection with impulse blading.

The movable blades of a turbine are subjected not only to a relatively high centrifugal stress, but also to a bending stress caused by the force of the motive fluid acting on the blades. It is well known that unless securely locked together, the blades will whip or vibrate, particularly so in turbines of large size which are adapted to operate at relatively high speed.

An object of my invention is to produce a new and improved blade shroud by means of which the outer ends of movable blades may be shrouded and securely locked together.

A further object is to produce a new and improved interlocking blade shrouding which is stronger, more simple and easier to assemble than other blade shrouding new in use and known to me.

These and other objects which will be made apparent throughout the further description of my invention are attained by means of apparatus embodying the features herein described and illustrated in the drawings accompanying and forming a part hereof.

In the drawings: Fig. l is a perspective view of a blade shrouding embodying my invention.

Fig. 2 is a perspective view of a modification of the shrouding illustrated in Fig. l.

Fig. 3 is a perspective view of a locking member employed in connection with the shrouding illustrated in Fig. 2.

In Fig. l I have illustrated a row of blades 5, each of which is provided with a shroud forming tip or head 6. As illustrated, the blade tips 6 are concave on the forward side and convex on the rear. the curvature being such that the tips nest together and form a continuous shroud over the ends of the blades. This arrangement insures the prop er spacing of the blades and eliminates the separately attached lshroud sometimes employed with such blading.

As shown, the concave rear face of eacr: blade tip 6 is provided with an integrally formed key 7 of bulb cross-section which adapted to lit in a similarly shaped groove or slot-8 in the convex or forward face of the adjacent blade tip and to thereby securely lock the tips together. The blades may be assembled by sliding the key 7 of one blade into the slot 8 of another, and so on. After a row of blades are assembled they may then be mounted on the rotor or turbine element in any suitable manner.

In Fig. 2 I have illustrated a row of blades 9 having integrally formed shroud ing members or tips 1 0 similar to those illustrated in Fig. l and adapted to nest together in the same manner. However. the interlocking arrangement for the shrouding members 1.0 comprises, as illustrated, a sepY arate key ll which is adapted to tit in grooves l2 in adjacent faces of the blade tips l0 and to thereby securely lock the tips together.

In Fig. 3 I have separately illustrated the key 1l. As shown, it is of double crosssection, the slots l2 in the shroud members l0 being of similar cross-section when matched together as the blades are assembled. By double bulb cross-section, I mean two cylindrical portions which are connected b v a relatively narrow web, although it is evi dent that T, triangular, or any other form of enlarged head may be employed on the interlocking key if desired.

The construction illustrated in Fig. 2 enables the blades to be assembled on the rotor or other turbine element in the usual manner, the key ll being subsequently driven in so as to interlock the shroud members and form, in effect, a continuous and rigid shroud, which may be easily and cheaply manufactured.

While I have shown my invention in but two forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed there upon as are imposed by the prior art or as are specificially set forth in the appended claims.

What I claim is 1. In combination with the impulse blades of a turbine, a shroud member formed'on the end of each blade and having convex and concave faces formed to cooperate With the faces of adjacent blades, and an interlocking` key for locking adjacent faces together.

2. A shroud member for blading having faces for cooperating with adjacent faces of other blades, and an interlocking key for rigidly locking said adjacent faces together.

8. shroud member for blading having faces for cooperating with adjacent faces of other blades7 and an interlocking laterallyv extending key for rigidly locking said adjacent faces together.

4. In combination. a turbine blade, i

shroud member formed thereon and cooperating With other shroud members to form a continuous shroud, and a key folA lowing the contour of the shroud members for locking said members together.

5. In combination with the impulse blades of a turbine, a shroud member formed on the end of each blade and having convex and concave facesvformed to cooperate with the faces of adjacent blades, and an interlocking key for locking adjacent faces together and following the curvature of said faces.

In testimony whereof, I have hereunto subscribed my name this 29th day of September9 1920.

JOI-IN EDWIN SNYDER.

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