General Electric Co. v. Bullock Electric Mfg. Co.

• Decision Date: 12 August 1907
• Citation: 155 F. 740
• Parties: GENERAL ELECTRIC CO. v. BULLOCK ELECTRIC & MFG. CO.
• Court: U.S. District Court — District of New Jersey

155 F. 740

GENERAL ELECTRIC CO. v. BULLOCK ELECTRIC & MFG. CO.

United States Circuit Court, D. New Jersey.

August 12, 1907

W. K Richardson and A. D. Salinger, for complainant.

Thomas F. Sheridan and Clifton V. Edwards, for defendant.

LANNING District Judge.

The complainant is the owner of the Morrow patent, No. 504,401 and of the Reist patent, No. 559,910, each for an armature for dynamo electric machines. They are capable of conjoint use. Each patent was issued to the complainant as assignee of the inventor. The defendant is charged with their infringement, and the defense set up as to each patent is invalidity of the patent and noninfringement.

The Morrow patent was applied for May 13, 1893, and granted to the complainant, as Morrow's assignee, September 5, 1893. The figures accompanying the patent are as follows:

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In the specification of the patent Morrow says:

'My invention relates to the construction of armatures; its object being to provide efficient and economical means for building up a laminated core and securing it to its support or carrier. In carrying out my invention I provide an internal cylindrical supporting shell, preferably carried by the usual armature spiders keyed to a shaft, and on the outer surface of said supporting shell longitudinal grooves are cut, into which corresponding projections on the inner surface of an annular armature core are adapted to fit, preferably making a dovetail or undercut joint. The core itself is composed of segmental laminae of such proportions that a predetermined number of them make one layer of the core; and in adjacent layers the segments are so arranged as to break joints. The said segments are provided at their inner edges with projections adapted to fit the grooves on the supporting shell, and registering with each other when the core is assembled. * * * Referring to Fig. 1, the cylindrical supporting shell A, is carried on spiders, A1, keyed to a shaft, A2, in the ordinary manner. At regular intervals along the outer surface of said supporting shell, A, are longitudinal undercut grooves, a, into which fit the dovetail projections, b, on the laminae, B. In making up an armature, the spiders and supporting shell are first assembled, and the laminae of sheet iron punched out in the shape indicated in Fig. I are slipped over the surface of the said shell, with the projections, a, in the grooves, b. After one layer is in place, another, breaking joints with the first, is put on, and so on, until the armature is completed. The dotted lines in Fig. 1 indicate the edges of the laminae in successive layers, showing the manner of breaking joints. It is obviously unnecessary to have the dovetail projections exactly fit the grooves, as shown in Fig. 1, and this is, moreover, manifestly undesirable, since much more care is thereby rendered necessary both in punching the laminae and in finishing the grooves. Slight modifications are therefore shown in Figs. 2, 3, and 4. In Fig. 2 the outer corners of projection, b, are rounded as shown at b1, while the outer edges of the groove, a, are rounded as shown at a1. A firm connection is thus afforded between the parts by the fit of the beveled edges of the groove and projection, while the necessity of a perfect fit at the acute angles, which would be difficult of attainment, is obviated. In Fig. 3, instead of rounding the edges of the groove, a, the laminae are punched so as to have a recess, b2, at the inner acute angles of the dovetail projections. In all of these arrangements, however, the projection, b, extends to the bottom of the groove, a, necessitating a careful milling thereof, as well as a smooth edge on said projection, in order to render the parts readily assembled. It is therefore preferable to chamber the groove, as shown at b3 in Fig. 4. * * * I am aware of patent No. 493,337, granted to Horace F. Parshall March 14, 1893, and therefore do not claim broadly an annular core supported by and dovetailed to an internal cylindrical support, but confine myself to a core made up of segmental laminae punched with internal dovetail projections. It is obviously of material advantage to make the laminae segmental, rather than annular, since the material from which they are punched can in this way be cut much less to waste, while by so assembling consecutive layers as to break joints, as above set forth, a practically solid structure is obtained. A further improvement consists in the modifications in the shape of the dovetail connections, as described, which render the parts much more readily assembled. By making the core with internal dovetail projections integral therewith, a greater depth of free iron for the traverse of magnetism is obtained.'

The patent has three claims, but the second claim only is alleged to be infringed. That claim is as follows:

'An armature core comprising layers of segmental laminae dovetailed to an internal supporting shell, in which the segments in consecutive layers break joints, substantially as described.'

Morrow was not the first to use segmental laminae in building up armature cores. Nor was he the first to use connecting projections and grooves between the spider and the laminae of an armature core. The British patent, No. 238, issued July 6, 1889, to Gibbs & Fesquet; the Geisenhoner patent, No. 414,900, dated November 12, 1889; the British patent, No. 19,011, issued October 18, 1890, to Hopkinson; the British patent, No. 4,858, issued February 7, 1891, to Kapp; the Lundell patent No. 461,795, dated October 20, 1891; and the Smith patent, No. 492,244, dated February 21, 1893-- all describe segmental laminae so assembled as to break joints. In all of these patents of the prior art, however, except possibly Hopkinson and Smith, the segmental laminae are fastened to the frame of the armature by bolts running transversely through the laminae and parallel with the shaft of the spider or armature. In Hopkinson, the method of fastening the laminae to the frame of the armature is not described, unless it be in the language of the specification, which declares that:

'The friction between the plates is sufficient to keep them in place just as well as if they were entire rings.'

In Smith's patent the inner peripheries of the laminae are welded together, thus obviating the necessity of bolts. In none of the abovementioned patents are there any dovetail connections between the spider and the armature.

In British patent No. 4,302, issued to Crompton March 3, 1884, and in United States patent No. 387,343, issued to Crompton August 7, 1888, the laminae are complete annuli, and are provided on their inner peripheries with dovetail grooves, into which are fitted the dovetail ends of the arms of the spider. The arms, however, at their inner ends, fit into the hub that surrounds the shaft in such fashion that the hub may be withdrawn, leaving the arms attached to and held in the laminae by reason of their dovetail connections with the laminae. In the specification of each of these Crompton patents it is said:

'This withdrawal of the central hub or hubs (as the case may be) greatly facilitates the winding of the armature coils onto the core. It also facilitates the insulation of the wires, and afterwards permits of easier access to the internal surface of the ring-core than has hitherto been the case, and thus lessens the cost of repairs or renewals of the coils.'

And in the Parshall patent, No. 493,337, dated March 14, 1893, the laminae are complete annuli. The inner periphery of each of the annuli contains a series of notches or grooves, which the patent declares are 'preferably of a dovetail or undercut shape. ' The specification further says:

'The notches are similarly arranged in all the disks, so that when the disks are assembled the notches will register and form grooves running lengthwise of the core.'

Longitudinal dovetail grooves are also cut in the outer surface of the spider. When the laminae are assembled on the spider and properly arranged, the dovetail grooves in the spider and those in the laminae are opposite to each other, and into them keys are fitted, though the specification says the keys 'may be cast integral with the shell,' or spider. The keys are made somewhat smaller than the grooves, and are fastened in the grooves by Babbitt metal or similar material poured therein. The patentee says:

'It is preferable to dovetail the grooves and keys, though any suitable shape may be given to them.'

This reference to the prior art is sufficient to present for intelligent consideration the question as to whether the Morrow patent contains any patentable novelty. It is conceded by the complainant that there was nothing novel in Morrow's use of segmental laminae. It is also contended by the defendant that there was nothing novel in Morrow's use of the dovetail connections between the spider and the laminae. But it will be observed that the functions of the dovetail grooves of the two Crompton patents are, first, to receive the ends of the spider arms for a driving purpose and, second, to hold the arms in place when the hub is removed. In the Parshall patent the function of the dovetail grooves is only to receive the keys, by which the laminae are locked to the spider, for a driving purpose. But when we turn to the Morrow patent we find that the functions of the dovetail connections between the spider and the laminae are, first, to lock the laminae to the spider for a driving purpose, and, second, to do so in such manner that they cannot possibly be driven...