US2096387A - Adapting sheet metal for receiving a screw - Google Patents

Description

Oct. 19, 1937. G; A. TINNERMAN 2,096,387

ADAPTING SHEET METAL FOR RECEIVING A SCREW Original Filed Dec. 30. 1956 )5 X3 WIIIIIII/%IIIIIIIL INVENTOR. GEO/e65 4. 77V/VE/F/7/9/Y B flwk/ ATTORNEYS.

Patented Oct. 19, 1937 PATENT OFFICE ADAPTING SHEET METAL FOR RECEIVING CREW George A. Tinnerman, Rocky River, Ohio, assignor to Albert H. Tinnerman, Cleveland, Ohio Original application December 30, 1936, Serial No. 118,216. Divided and this application March- 26, 1937, Serial No. 133,202

6 Claims.

This invention relates to threadless fasteners which are made of sheet metal, and is a division of my copending application, Serial No. 118,216

filed Dec. 30, 1936.

An object of my invention is to make a-threadless fastener that can be made from ordinary commercial quality cold rolled steel and that possesses the holding power of fasteners made from spring steel. In addition, the invention contemplates a shape of fastener, which enables it to be formed out of sheet panels that comprise an integral part of an assembly, such as automobile bodies, gas or electric ranges, furnace jackets, metal furniture, metal partitions, refrigels, airplane cowlings, lamp bases, signs or many kindred types of assemblies which employ metal I ber.

sheet materials, as a part of their completed form. A further object of the invention is to make a fastener which may be constructed independently I of the panel with which it is intended to be used so that it can be suitable for holding assembly panels which are made of such materials as fibre board and glass or vitreous coated metal sheets. Referring now to the drawing, Fig. 1 is a top plan view of a fastener embodying my invention; Fig. 2 is a side view of a fastener shown in Fig. 1; Fig. 3 is a longitudinal vertical section taken through the fastener of Fig. l and showing it in use with a threaded member; Fig. 4 is a top plan view of a panel having fasteners embodying the present invention formed therein; Fig. 5 is a vertical section through a forming tool illustrating a step in the forming of the fastener; Fig. 6 is a section similar to that in Fig. 5 and showing another step in the formation of the fastener; Fig. '7 is a cross sectional view taken on the line 'i1 in Fig. 2; Fig. 8 is a top plan view of. a fastener having a modified form of a bolt opening therein, and Fig. 9 is a side view of a fastener shown in Fig. 8. I

The fastener which I have illustrated, has been designed to have sufficient strength even though made out of cold rolled steel to withstand the endwise pull which is exerted during the tight ening operation of the threaded holding mem- The fastener is adapted to be made either in individual units or in the form of an impression on a sheet panel. Thus, in Fig. l the individual fastener is shown as having abody portion ID from which thread engaging portions H are deformed. These portions, in the form shown, include wall surfaces i2 which are inclined to the body portion and which terminate in substantially fiat portions l3 that are bent inwardly out of the plane of the inclined wall surfaces l2 and are pitched to correspond to the helix of a threaded member with which the fastener is intended to be used.

In the preferred arrangement, the portions l3 have a width that is substantially equal to the depth of the thread on the bolt with which the fastener is intended to be used, as a result of which the force exerted during the tightening operation does not impose an objectionable bending moment upon the thread engaging part of the fastener. The portions l2 may be either substantially flat or slightly curved transversely, but in either case, the surface is such that its intersection by any plane passing at a right angle through the body portion, and in a direction in which the tongues extend, would be a straight line.

In making the thread engaging portion, I prefer to utilize a tool which will slit the stock along parallel lines [5, and then draw out of its plane that portion which lies between the slits IS. The slitting and drawing operation may be performed by dies'20 and 21 respectively; the die 21 having a cavity 22 into which the metal is adapted to be pressed by the die 20. This operation imparts toughness to the metal by cold working it, the operation comprising a stretching as well as a forming operation, as a result of which the area of the deformed metal is larger than the area of the opening from which it has been drawn.

Fig. 5 shows the position of the dies during the drawing operation while Fig. 6 shows the position of them during the piercing operation. In Fig. 6, the deformed metal fills the cavity in the lower die while the punch23 which is positioned centrally within the die 20 extends through the metal, thereby shearing oil a part of it, so as to form the aperture, through which a threaded fastening member 25 may extend.

The die 20 may have a yieldable connection, by means of a spring 26, with a plunger 21, that is adapted to be reciprocated in any well known manner. The spring 26 is sufficiently strong that the metal is drawn from the body portion of the fastener and forced against the wall of the cavity 22 before the punch 23 pierces the metal to form the thread receiving aperture. A convenient way of supporting the punch 23 within the carrier or plunger 21, is to provide a shoulder which abuts the carrier against the Wall 4|, which forms the seat for the spring 26. The die construction shown may be satisfactorily used either for forming individual fasteners or for making the fastener impressions in the body of a sheet was deformed. This may be accomplished either by pressing the metal with suflicient force to make it flow laterally, or by bowing inwardly the longitudinal connecting strips 9 on the body of the fastener. In either case, the connecting strips 9 provide an abutment as shown by the broken lines I I a in Fig. 7 against which the laterally projecting ends of the tongues may engage in case they are drawn to an excessive degree during the bolt-tightening operation. In this way, the tongues are prevented from being pulled through the fastener at any time.

In Figs. 8 and 9, I have shown a modification of my invention wherein the bolt engaging portion comprises a strip 30 that is drawn from the base in'the same manner as heretofore described in connection with the fastener of Fig. 1, but wherein the bolt receiving opening is formed by severing the strip only at one edge as at 3 I. Such severing operation forms the tongues 32 and 33 which may be bent in opposite directions so as to make the marginal edge of the bolt receiving opening in the form of a helix that corresponds to that on the thread with which the fastener is intended to be used.

A fastener made in accordance with the present invention has sufllcient strength to resist the tendency of the threaded member to pull through, wherefore it can be made of cold rolled stock and used satisfactorily with a threaded holding member that is commercially known as a woodscrew. The cold working of the metal, resulting from the forming and stretching operation, imparts a degree of hardness to the thread engaging portions of the fastener which makes it suitable for use in impressions that are provided in multiple from an unhardened sheet metal panel. Thus,'I have greatly extended the usefulness of threadless fasteners in automotive and cabinet assembly. A further advantage of my invention is the fact that the forming tools may be satisfactorily used either for making individual fasteners or for making individual impressions in a sheet metal panel upon a single stroke of the reciprocating die.

I claim:-

1. The method of adapting unhardenedsheet metal for the reception of a screw or the like, which comprises, slitting, drawing and stretching an area of the sheet out of its plane, thereby providing a substantial wall projecting out of said plane of greater area than the space from which it is drawn, and providing in the wall thus ob- 1tlalined an opening to receive the screw or' the 2. The method of adapting unhardened sheet metal for the reception of a screw or the like, which comprises, slitting, drawing and stretching an area of the sheet out of its plane, thereby providing a substantial wall projecting out of said plane of greater area than the space from which it is drawn, providing in the wall thus obtained an opening to receive the screw and distorting a portion of said wall adjacent the opening thereby providing a thread engaging portion which lies on a helix corresponding to the threads of the screw to obtain uniform threaded engagement therewith.

3. The method of adapting unhardened sheet metal for the reception of a screw or the like, which comprises, drawing an area of the sheet out of its plane to provide a substantial wall projecting out of said plane of greater area than the space from which it is drawn, stretching the wall thereby providing a wall portion which is hardened and substantially flat, and providing in the said hardened wall portion an opening thereby presenting a hardened thread engaging out of its plane to provide a substantial wall pro- I jecting out of said plane ofgreater area than the space-from which it is drawn, stretching the" wall thereby providing awall portion which is hardened, and providing an openingin the said hardened wall portion thereby 4 presenting a hardened thread engaging portion adapted to engage the screw on a planesubstantially at right angles to the axis thereof'jwhereby said projecting wall bolsters the said hardened thread engaging portion and prevents ,the same from being pulled through the sheet ;when the screw.

is drawn up, and distorting'said'thread engaging portion to lie on a helix corresponding tothat of the threads of the screwto obtain most effective, uniform threaded engagement therewith.

5. The method of adapting unhardened sheet metal for the reception of-a screw or the like, which comprises, slitting-and drawing an area of the'sheet out of its plane, thereby providing a substantial wall" projecting out .of-'said plane of greater area tha'ngthe spaceir'om which it is drawn, and cold working said wall thereby pro viding a stretchedwall portion having an element projecting laterally beyond the outline of the space from which the wall is drawn, and pro-' viding in the said wall an opening to receive the screw. t y I I 6. The method (if-adapting unhardened sheet metal for the receptioh-= of "escrow or'the like,

- which comprises, slitting, drawing and, stretching of an area of the sheet out ofitsplane to. provide a substantial wall projectingout of said I plane of greater area than the spacelfrom which it is drawn and providing in the projecting wall thusobtained an, opening thereby presenting means for receiving the screw comprising av pair of independently movable projecting wall members adapted to' coact in engaging the screw or the like.

GEORGE A. TINNERMAN, I

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