US1300275A - Screw-threaded fastening. - Google Patents

Description

C. F. JOHNSON. SCREW THREADED FASTENLNGx APPLICATION FILED SEPT. a. 1914.

Patented Apr. 15, 1919.

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CAEL E.. JOHNSON, or MILWAUKEE, wIscONsIN, AssIeNOE ro JOHNSON sEEvIoE comm, or MILWAUKEE, wxsOONs'IN, A GORPOEATION or wrscoNsIN.

'SCREW-THREADED FASTENIN'G.

To all whom t may concern Be it known that I, CARL F. JOHNSON, a citizen ofthe United States, residing v at Milwaukee,in the countyV of Milwaukee and State of Wisconsmhavle invented certain new and useful Improvements in Screw- Threaded Fastenings, of which the follow ing` is a specification.

- ing a novel driving contact, so formed and so related to the object held by the screw that the latter may be removedmnly by means of a special key or vwrench provided `for the purpose.

The object of the. invention is topprovide'v a device of this class which is peculiarly diiiicult to turn with any implement etherI larger'- in diameter than thev head of the annular flange of a circular socket wrench,

which enters into locking engagement-withthe-screw by means oi. an eccentric long1.

tudinal pin. 'The counter-'sinking of the head prevents the releasing of the screw by. means of pliers, while the use o f a smgle and only slightly eccentric opening in the head 'prevents the use of this as the-sole means of turning the screw. It is possible by careful proportioning of the parts to produce ascrew wihich can be removed 'onl ywith the specially designed wrench whic r accurately fits the screw head.

Preferred embodiments of the-invention are illustrated in the accompanymg draw gure 1 is an axial section through a screw embodying m inventiomshowingthe ',lsameuin position wi the wrenchapplied;

mrtly 1n elevation, showing the vfrom j each his invention relates to screw. threaded fastenings and particularly to a scnew hav-vA .rounded surface as on ashar the screw, such 'recess' being only slightly Bist-a view longitudinal sec-'- Specification or Letters Patent. Patented Apr, 15, 1919, Application led September 8, 1914. Serial No. 860,047. I

Fig. 4 is a perspective View of the screw i land wrench; and

Flg. 5 1s a view similar to Fig. 3 illustrat' Gis provided withcountersunk aperture 8 andthe piece 7 with a threaded hole 9 to receive the threaded portion 10 of the screw. The head 11 ofthe screw is cylindrical in shape. and is preferably slightly rounded at its upper edge 12,V in order to prevent the successful use of a taper socket wrench or the hke, as this will not hold so well on ,a

edge.

Ace

.A longitudinal hole'13 whlch is eccentric 70 with respect to the axis of the screw extends from the head 1'1 to the end of the threaded portion of the screw. It is not essential however that this hole extend. the entire length of the screw provided it i's given sufficient depth to receive the wrench pin and hold the same firmly.; When the 4screw is ,in place the head 11 lies wholly within'the l countersunk 'recess 8 of the piece 6,"o'nly a very small annular space intervening be- -tween the screw head and the sidesvof the recess. To turn the screw, I make use of a wrench having 'a stem 14 and a cylindrical socket 15 whose annulary rim extends into the space -between the sides of the head 11 and the walls of the countersunk recess 8. This wrench carries an eccentric longitudinal pin 16 the eccentricity of the pin 16 being the same as that of the hole 13 of the screw and when the wrench is applied to the Ascrew head the pin 16 is the means by which thel screwis turned. The wrench may be provided with a milled head 17 or any other suitable means for turning it.l

' In Figs. 1 to 4 the invention is illustrated as applied to a very small machine screw, the drawm 'being on anenlarged scale. The device as a particular advantage in small size screws because the screw has suiicient frictional engagement with the pin 16 to be held thereby so that a ready means of hold'- in the screw' during insertion is provided.

n Fig. 5, I illustrate the device as applied to a button head screw, or other screw having a substantially hemispherical head.. These Screws, 111e the mes sewn in Figs. 11

to 4, are preferably mounted in countersunk holes and for similar reasons, but as the hemispherical hea'd oilers very little opportunity for the use of pliers or taper socket wrenches, this latter form is sometimes preferable where extreme safety against removal is necessary. Obviously the form shown in 1 very heavy. Similarly as the flange l5 is in contact with the head 11 all around the same itto'o can be made relatively thin, so that onl a very slight space between the head 11 an vthe sides of the countersunk recess 8 is necessary. Consequently, and this is particularly true in the smaller sizes, there is no opportunity for the insertion of pliers or other clamping devices while the hole 13 may be made so small that it offers no adequate means for turning the screw except by means of the particular type of wrench illustrated and so proportioned as to tit the screw accurately. In other words the arts may be so nicely proportioned that on y a closely fitting key will have strength suiicient to turn the screw.

The embodiment shown in Fig. 5 may be similarly designed.

Having thus described my invention, what I claim is 1. As a new article of manufacture, a screw .having a threaded body and a driving end portion of substantially circular con; tour, said driving portion provided with one and only one longitudinal hole located eccentrically with reference to the axis of the screw.

2. The combination of a screw having a single longitudinal hole eccentric with re spect to the axis of the screw, and having a driving end\ portion of circular contour; and a removable driving key therefor, having an eccentric pin adapted to enter the hole in said screw, and having a circular projec- 'tion adapted to mate with the driving end portion of the screw to hold the screw and key in axial alinement.

3. The combination of a member having a threaded hole; a member having a countersunk hole; a screw holding said members together and having a headlying substantially entirely Within said countersink and nearly but not quite filling the same in the direction of its diameter, said screw having a single eccentric hole in its exposed end; and a turning key having. a thin flange adapted to embrace the head of said screw within said countersink and having an eccentric pin adapted to enter the hole in said screw.

4. In combination with a body having a screw seat, the outer portion of which seat is of slightly larger diameter than the screw it is to receive; a screw adapted to fit and fill the lower or inner portion of said seat but to leave an annular space about its outer or head portion, said screw having an eccentric hole or socket parallel with its longitudinal axis; and an implement for turning said screw, having an annular rim or flange to (it the screw-head and occupy the annular space about said head, and having also an eccentric pin to enter the hole or socket in the screw.

Inftestimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

CARL F. JOHNSON.

Witnesses:

HELEN Go'i'rsLEBEN, L. M. WALSH.

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