Caster Socket Co. v. Clark

110 F. 976, 1901 U.S. App. LEXIS 4936
U.S. Circuit Court for the District of Connecticut·Decided September 20, 1901·No. No. 1,027·Published

Opinion

TOWNSEND, District Judge.

The complaint alleges infringement of United States patents No. 318,533, dated May 26, 1885, to Julius Berkey, and No. 594,937, dated December 7, 1897, to Demi B. Denton, both for sockets for furniture casters. Defenses are invalidity of patent, no capacity for conjoint use, denial of infringement. The object of these patents is to furnish a socket for furniture casters such that the casters, when inserted, will not drop out on lifting'the article of furniture under which they are placed, but such that the casters can be readily removed by the use of slight force when desired. At the time of the issue of the Berkey patent it was common to make caster sockets in two separate halves. The specification of the Berkey patent describes the construction as follows;

“The socket is made in two parts, and wben in use tlie two parts are put together so as to form the socket, and are driven into the opening in the furniture provided ,to Receive the same. * * * A represents a half socket of, iron or other metal, having the tongue, a, formed by casting the half socket and tongue in one piece, the tongue projecting or inclining inwardly, as [977] shown in Fig. 3. B is a half socket without the tongue, a, but. having a ridge, c, and a depression, d, for holding the ball, C, of the caster shank. * * * The shank is in the ordinary form, except it is provided with the ball or enlarged portion, O, so as to be held in place by the springs or spring and ridge, e. Two of the half sockets A, when put together, form a com-ísete socket, or the half socket A and half socket B are put together to form a complete socket.”

The single claim is as follows:

‘Tu a caster socket, the half socket A, provided with a tongue, a, integral with and formed of a part of the half socket A, substantially as and for the purpose described.”

As appears by the description of this patent, the half socket has a spring made from the same piece with the socket, and integral therewith, projecting from the lower part of the socket upward and inward. The pintle or stem of the caster has a ball or enlarged portion at the upper end. When inserted in the socket, the ball presses the spring backward until it has passed the upper end of the spring, when the spring again inclines inward, and presses against the stem of the caster just below the ball; thus, when the piece of furniture is lifted, the caster is held in place by the pressure of the spring, but a firm pull by the hand upon the caster will suffice to overcome the force of the spring and remove the caster. When the half sockets A and B are used, the upper end of the spring combines with the ridge of the socket B to hold the ball, and thereby the caster in place; when the two half sockets A are used, the two springs combine their action with the same result. The specification of the Denton patent uses the term “caster case” instead of “socket.” In this patent, the caster case or socket is made of one piece of metal, not divided in halves. The socket is open at the top, and split, or made with a slot, the split or slot extending a short distance from the top downward, the body of the case from the lower end of the slot to the track plate • being made solid. The upper end of the case from the bottom of the slot upward is made somewhat smaller than the body of the case. The upper end of the pintle or caster stem is made bulbous shape. When the stem is pressed into the socket, the parts of the upper eu<l of the socket on the different sides of the split or slot spring outward allowing the bulbous-shaped end of the stem of the caster to pass between and above them, when they spring back to their original position, and press against the stem below the bulbous-shaped part, thus holding the caster in place. As in the Berkey construction, so in the Denton construction, the caster will not drop out when the furniture is lifted; but a firm pull upon it will separate the parts of the socket adjoining the slots, and allow the caster to be removed. The single claim of the Denton patent is as follows :

“In a case for furniture casters, a solid body extending up for a distance from the track plate, the upper end contracted or made smaller and slotted down to the line of contraction so that it can he made to spring apart, and the end left open, so that the bulbous end of a caster stem may be forced through and supported by resting upon the end of the ease, substantially as and for the purpose set forth.”

The only substantial difference between the construction of the Berkey patent and that of Kane and Brown, No. 52,420, of 1866, is [978] that the spring of the Kane and Brown patent is riveted upon the interior of the socket, while that of the Berkey patent is integral with the socket. The essence of the claimed invention is this integral spring. This is squarely and frankly and repeatedly stated by complainant’s counsel in their brief. Thus, after describing eight patents for the same purpose from 1854 to 1876, all of which they claim to have been unsuccessful, they say of the Berkey invention:

“He used a cast-metal socket of substantially the same form shown by several earlier patents. He used a pintle with a bulbous head of substantially the same form shown by several earlier patents. He used a spring engaging this bulbous head, and removably holding it in position. His improvement and his invention consisted, and consisted only, in making the spring integral with the socket, of the same material, and formed by the same operation, instead of making the spring of another material by separate operation, and then by a further operation attaching the two together. It is evident that greater • simplicity, cheapness, and efficiency were thereby obtained. The patent is not a broad one in the sense that it was the first for its purpose; on the contrary, the margin of invention upon which it stands is narrow. We hope to convince the court, however, that this margin, though narrow', is ample.”

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Caster Socket Co. v. Clark, 110 F. 976, 1901 U.S. App. LEXIS 4936 (circtdct 1901).

110 F. 976 (Caster Socket Co. v. Clark) — published by Counsel Stack Legal Research, free access to 12M+ legal documents.

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