Untitled record

B. T. ANDREN

Dec. 16, 1930.

ATTACHING TAPPED NUTS TO METAL PLATES

Original Filed July 15, 1927

Re. 17,907

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Reissued Dec. 16, 1930

Re. 17,907

UNITED STATES PATENT OFFICE

BIRGER TORVALD ANDREN, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO A. O. SMITH CORPORATION, OF MILWAUKEE, WISCONSIN, A CORPORATION OF NEW YORK

ATTACHING TAPPED NUTS TO METAL PLATES

Original No. 1,705,403, dated March 12, 1929, Serial No. 205,983, filed July 15, 1927. Application for reissue filed April 2, 1930. Serial No. 441,156.

The invention relates to an improvement in the means for and method of securing tapped nuts in perforations formed in thin metal plates, so that such nuts will be in C proper position and be held against rotation at the time that bolts or screws are entered into the threaded holes thereof.

The object of the invention is the provision of means for attaching specially shaped nuts 10 to metal plates or other parts in a simple manner, so as to place the stresses of the screws engaging the nuts directly upon the plate and so relieve the joints from strain, and this result is accomplished by producing 15 upon one side of the plate an embossment Which co-operates with the nut and serves to interpose resistance to the stresses by placing the metal of the embossment under compression.

Having thus indicated the nature and purposes of my invention, I will now describe in detail the actual practice of the same, and will point out in the appended claims the novel features residing in the invention.

The present application forms a continuation in part of my co-pending application, Serial No. 149,100, filed November 18, 1926, for all the common subject matter disclosed therein.

In the accompanying drawing:

Fig. 1 is an axial, central sectional view through a nut blank.

Fig. 2 is a like view after the blank has been subjected to the first upsetting opera35 tion.

Fig. 3 is a like view after the blank has been subjected to the final shaping operation.

Fig. 4 is a like view showing the nut as completed by the tapping operation.

Fig. 5 is a plan view of the nut as shown in Fig. 4.

Fig. 6 is a perspective view of a plate showing the outline of one of the perforations in which the shank of a hexagonal nut is re45 ceived, together with the embossment thereon, and also a hexagonal nut as secured to the plate.

Fig. 7 is a like view, but-showing a cylindrical nut.

W Fig. 8 is an enlarged sectional view through the plate and nut, on the line 8—8, Fig. 6, showing the embossment and concavity formed in the plate, and the manner of anchoring the nut in the perforation of the plate, without disturbing the thread of the ₆₅nut, together with a cap screw attaching a part to the plate.

In many classes of work in making the desired connections, the nuts are placed loosely in or over the perforations in the plate and _eothere held by hand while the bolt or screw is being inserted. This practice involves a very tedious and time consuming operation, under certain conditions, and to relieve the situation, various adjunctive devices for holding ¢5 the nuts in position while entering the bolts or screws where the work is close have been resorted to. But such devices are costly, and require a wasteful expenditure of time in their application. _7o

In the practice of the present invention, perforations of non-circular contour, preferably polygonal are formed in the plates at the desired places by a simple punching operation. At the time of punching the hole in 75 the metal plate, the metal of the plate surrounding the perforation is displaced laterally so as to form a slight embossment at one side, and a slight concavity at the other, which construction serves to place the metal ₈₀of the plate in the region of the perforation under compression when a force tending to reduce the embossment is exerted. Fitted in the perforation, is the correspondingly formed reduced shank of a specially con- ₈₈structed. pierced nut, which prior to its insertion in the perforation in the plate is properly tapped. By reason of the special construction of the shank formed upon one side of the nut, the shank may be expanded 90 laterally so as to fill the perforation in the plate and engage the wall thereof and rigidly secure the nut in position. This very desirable result is achieved without disturbing the thread of the nut, the intervening metal pre- 95 venting the flow toward the thread, and without disturbing the angular position of the embossment upon the plate. In upsetting the shank of the nut, the rim or edge at the free end of the shank projecting through the 100

17,907 embossment on the plate and into the concavity at the opposite side, is pressed in the expanding operation so as to lie substantially flush with the surface of the plate within the ₆ concavity, and slightly within the side planes of the plate. The opening in the nut flares outwardly to the end of the shank, so that the tapering opening thus produced acts to center the threaded end of the screw and ₁₀ direct it into engagement with the nut. As so arranged, the nuts are always in the desired positions, and the work of connecting the parts is greatly facilitated..

In referring now to the drawing, the nu₁₅ meral 10 indicates a nut blank, which may be produced by punching from a metal plate of the desired gauge, or by cutting from bar stock. The nut blank may be cylindrical or polygonal, it matters not which, and will be 20 axially perforated at 11, in the customary manner. See Fig. 1. The nut blank 10 is then subjected to the action of upsetting dies, which will form the depression or recess 12. The latter flares outwardly from the perfo25 ration 11 at one side of the nut blank. At the time the displacement of the metal occurs in the formation of the depression 12, the adjacent metal is moved radially to form the transverse enlargement 13 on the end of the 30 nut blank. See Fig. 2.

The blank is then subjected to the action of another set of dies, which compress the metal to form the hexagonal shank 14, or of a form other than cylindrical, but of reduced 35 diameter and the circumferential rib 15 about the median line of the nut, with a circular shoulder 16, at the base of the shank, such shoulder connecting the shank 14 and the rib 15. See Fig. 3. The f ace of the shoul40 der 16 which extends transversely of the axis of the nut may be slightly dished, as shown, so as to receive the embossment and effect a close contact between the outer marginal edge or rim 16 of the shoulder and the 45 face of the embossment on the metal plate to which the nut is to be attached. The nut 17 is then completed by tapping the perforation 11 therein, so as to provide the same with a thread, as at 19. The depression 12 50 in the end of the shank of the nut tapers inwardly from the marginal edge or rim 18 directly to the threaded opening 19, this constituting a centering means for the leading end of the attaching screw, conducing to 55 a quicker engagement of the screw with the nut.

In Figs. 6 and 7, the numeral 20 indicates a metal plate, suitably perforated as at 21 for the reception of the shank 14 of the nut. eo The outline of the perforation 21 in the plate 20 should conform substantially to the exterior configuration of the shank 14 of the nut, so that when assembled the non-circular formations of these parts will engage each ⁰⁸ other, and there can be no rotation of the nut while the threaded end of a screw is entered therein.

Viewing Figs. 6, 7 and 8, it will be seen that the metal of the plate 20 surrounding the perforation 21 therein, is displaced laterally from the plane of the plate. This condition * is produced in the punching operation, and the slight embossment 22 upon one side of the plate is adapted to be received in the dish of the shoulder 16 on the nut, when the shank 14 is passed through the perforation 21. .In ¹⁰the upsetting operation on the upstanding edge or rim 18 of the shank of the nut, an outward flow of the metal thereof takes place. This is due to the fact that when the upsetting pressure is exerted, the thicker part of the inclined wall of the flaring recess in the shank resists the inward flow of the metal of the shank, and such flow follows an unopposed outward course, to spread the metal into close engagement with the walls of the perforation 21 in the plate, with a wedging action. At the same time, the dished shoulder 16 of the nut is brought into close engagement with the face of the embossment 22 on one side of the plate 20, and a good contact is effected. The projecting edge or rim 18 is broken down and made to lie flush with the surface of and within the concavity formed on the other side of the plate by the displacement of the metal which produces the embossment. In the upsetting operation, the end of the shank 14 of the nut is made to lie slightly within the side planes of the metal plate, and within the concaved side of the lat- ,,₍₎ter. The thread of the nut is not disturbed, inasmuch as the thread, extending only to the bottom of the depression or recess 12, is removed from the region of pressure. The construction thus provided may be put to its _IOftintended uses without further threading of the nut. In these operations, the embossment on the plate 20 is placed under compression, and so creates a yielding resistance to the stress upon the screw. This prevents the ρ_(&gt;joint at the nut from bending, and the nut from becoming loose.

Fig. 8 shows the use and operation of the invention, it illustrating how a screw 23, entered into the nut 15, serves to secure an nr, attachment 24 to the plate 20, and maintain a tight connection between the plates, the pull upon the nut being against the displaced portion of the plate, the concavity providing a clearance permitting movement under com- ι·?ι, pression. Deforming the plate . 20 in the manner described, causes it to act as does a nutlock or spring washer.

The simple operations incident to the production of the invention contribute to the i2f economical use of the latter. While a specific use of the invention has hereinbefore been set forth, the invention is not to be so limited in its use, but obviously may be put to other uses than that stated. I3t

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