US3003134A - Service block - Google Patents

Description

Oct. 3, 1961 w, HERMAN ETAL' 3,003,134

SERVICE BLOCK Filed July 17, 1958 ..I "ll I v w 1N VENTOR W ILL THO IAM P. HER-MAN I IAS KENNETH HOBSON ATTORNEY limited States Patent Q 3,003,134 SERVICE BLOCK William P. Herman, Providence, and Thomas Kenneth Hobson, Cumberland Hill, R.I., assignors, by mesne assignments, to North American Philips Company, Inc,

New York, N.Y., a corporation of Delaware Filed July 17, 1958, Ser. No. 749,238

1 Claim. (Cl. 339-61) Our present invention relates to electrical connections, and has particular reference to a" novel construction of a service block. Y

The principal object of'the present invention is to provide a service block having an integral one piece body of resilient material in which the contact blades and cord lead wires are anchored without screws, bolts, soldering or other outside anchoring means.

Another object of the present invention is to provide a service block having a single set of contacts for the vertical and transverse connections.

A further object of the present invention is to provide a service block construction which effects a saving in materials and assembly costs.

Another object of the present invention is to provide a service block which is simple in construction, having a minimum number of readily assembled parts.

With the above and other objects and advantageous features in view, our invention consists of a novel arrangement of parts, more fully disclosed in the detailed description following, in conjunction with the accompanying drawings, and more specifically defined in the appended claims.

In the drawings,

FIG. 1 is a perspective view of a service block embodying our invention.

FIG. 2 is an enlarged section taken on line 2--2 on FIG. 1.

FIG. 3 is a section taken on line 3 3 on FIG. 2.

FIG. 4 is a section taken on line 44 on FIG. 2.

FIG. 5 is an enlarged perspective view of one of the contact blades.

The conventional service block comprises a plug body attached to the end of a cord lead wire and having provision for the insertion of male contacts at the end and at each side. This provides an extended cord connection into which three lines can be plugged. The service block is therefore normally provided with a pair of elongated vertically disposed female contact blades to which the cord lead connection is made at the upper end and a transverse contact blade in contact with each vertical blade in the form of a cross for handling the horizontal connections. The body of the plug must be extended at each side to house the transverse blades. This type of construction is bulky and difiicult to assemble.

The present invention provides an improved construction of service block in which only a single pair of ver-- tical blades are mounted. The transverse blades are eliminated and the transverse contacts are staggered so that they can make contact directly with the vertical blades within a minimum space. This construction produces a considerable saving in materials and in assembly costs.

Referring more in detail to the drawings illustrating our invention, the service block shown in FIGS. 1 to 5 inclusive comprises an elongated body portion of resilient dielectric material, such as soft rubber, and having a cord lead connection 11 entering at the upper end. The body portion 10 is generally oval in cross section and tapers inwardly at the upper end as shown in FIG. 3. Referring to FIG. 3, the body 10 is provided with a cord chamber 12 into which an integral separating tongue 13 extends. A pair of vertical slots 14 and 15 3,003,134 Patented Oct. 3, 1961 2 extend downwardly from the chamber 12 in spaced parallel relation through the plug.

The bottom end of each slot is provided with a flared portion 16. Just above the flared end 16 each slot is cut inwardly towards the center to form an abrupt shoulder 17. The inner .wall 18 of the cut portion extends upwardly from the shoulder -17 at a slight angle terminating in a larger upper shoulder 19. This forms a cut out portion adjacent the lower end of each slot. Slightly above the midway point, each slot 14 and 15 is provided with an integral wall portion 20 extending from the outer wall of each slot and then inwardly to form a restricted slot portion. Similarly at the upper end of each slot, at the base of the chamber 12, the outer side wall is provided with an inwardly extending portion 21 forming a restricted slot portion at this point. Between the central separating tongue 13 and the upper end of each slot the body portion is provided with a shouL der 22.

Referring to FIGS. 2 and 4 the body portion 10 is provided with an integral extended portion 23 at right angles to the slots 14 and 15 and a similar integral extended portion 24 on the opposite side of the body portion and extending below the portion 23. The portion 23 is provided with a pair of transverse slots 25 having flared ends 26 and extending through the vertical slots 14 and 15 and into the opposite wall of the body portion. The slots 25 are in the same plane as the slots 14 and '15. The extended portion 24 is similarly provided with slots 27 extending through the slots 14 and 15 and slightly below the slots 25 leaving the material 28 as a separator between the slots. Since the slots 25 and 27 permit the inserted male blades to pass beyond the vertical slots 14 and 15, the portions 23 and 24 need only be extended slightly from the plug body to give the necessary thickness.

Each slot 14 and 15 is provided with a contact blade shown in FIG. 5. Each blade comprises an elongated rectangular body portion 29 which maybe stampedfrom sheet stock in strip form. At the bottom end, each blade is reentrantly bent to form a folded portion 30 having a bent end 31 extending angularly from the plane of the blade. The bottom end is also provided with an opening 32 for assembly purposes. The. body portion 29 may be slightly wider than the conventional blades to provide a greater contacting area for the transverse contacts.

The upper end of each blade is provided with an integral cord connecting section 33 having two pairs of spaced tangs 34 and 35 extending laterally. As shown in FIG. 3, a cord lead wire having a bared end 36 is laid between the tangs of each blade and folded in by a crimping tool. The wire is grabbed in two places, and for strain relief the insulation may be extended so as to be caught by the upper tangs 35. In assembly, the pair of blades are pulled into the slots 14 and 15 so that the folded portion enters the cut out. The bottom end of each blade abuts the shoulder 17 and the bent portion 31 abuts the shoulder 19, looking the blade in place. In addition, the wire assembly and tangs 34 rest on the shoulders 22 at the upper end. The restricted slot portions 20 and 21 serve to retain the blades against the inside wall of each slot.

With the parts thus assembled, a male connector can be inserted through the bottom, contacting the blades 29 in alignment, and male connectors can be inserted in the slots 25 and 27, contacting the blades 29 transversely. The need for cross contacts is eliminated thus effecting a saving of labor and material. Furthermore, by staggering the cross slots 25 and 27, a saving is effected in the body material by reducing the slot extensions 23 and 24 to a The above construction therefore provides an assembled 3 service block preferably formed of resilient soft rubber. The use of a single set of contact blades materially reduces the cost and the slot arrangement reduces the bulk. Other advantages of the present invention will be readily apparent to a person skilled in the art.

We claim:

A service block comprising an elongated one piece body of resilient material having an upper cord receiving chamber and two spaced parallel vertical slots extending downwardly from said chamber through said body, said body portion having a pair of transverse slots intermediate the ends of said vertical slots and extending inwardly from opposite sides in vertically ofiset relation, said transverse slots communicating with said vertical slots, an elongated straight flat female contact blade in each verticalslot, and an electrical cord connection anchored to the top of each blade in said cord receiving chamber, said blades and body portion having cooperating means for anchoring said blades in said vertical slots, said body portion having a restricted slot portion in each vertical slot to retain eachblade against the inner wall of each vertical slot.

References Cited in the file of this patent UNITED STATES PATENTS 2,210,215 Herman Aug. 6, 1940 2,609,414 Weisberg Sept. 2, 1952 2,714,713 Parajon Aug. 2, 1955 2,799,839 Weiss July 16, 1957 2,869,093 Benander Ian. 13, 1959

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