US2136072A - Automatic plumb bob - Google Patents

Description

Nov. s, 1938. E, s BUSH 2,136,072

AUTOMATIC PLUMB BOB Filed July l5, 1956 mmky A Traer/EV Patented Nov. 8, 1938 PATENT OFFICE AUTOMATIC PLUMBI BOB Eugene S. Bush, St. Louis, Mo., assigner to Bush- Harman Products, Inc., St. Louis, Mo., a corporation of Missouri Application July 13, 1936, Serial No. 90,376

1 Claim.

This invention relates generally to plumb blobs, and more specifically to a plumb bob the supporting cord of which is connected to the weight in such manner that when not in use the cord will be automatically wound up within the bob,

and wherein any length of cord may be withdrawn from the bob and the bob clamped to the cord to restrain the operation of the cord-winding means until it is desired to release same, the

'10 predominant object of the invention being to provide an extremely simple device of this type,

which is an improvement on the automatic plumb bob covered by United States Letters Patent 1,357,270, granted to me on November 2, 1920. Fig. 1 is a view of the improved plumb bob illustrating same partly in elevation and partly in vertical section.

Fig. 2 is an enlarged vertical section on line 2 2 of Fig. 1.

Fig. 3 is a section on line 3-3 of Fig. 2.

Fig. 4 is a section on line 4-4 of Fig. 2.

Fig. 5 is a section on line 5--5y of Fig. 2.

Fig. 6 is a fragmentary detail showing the manner in which an end of the cord is attached to the reel of the plumb bob.

Fig. 7 is a perspective of a part of the cordwinding mechanism of the improved plumb bob.

In the drawing, wherein is shown for the purpose of illustration, merely, one embodiment of the invention, A designates the improved plumb bob generally, said plumb bob including a bob of weight I and a supporting cord 2. I'he bob I is of the usual `shape and comprises a lower section 3 and an upper section or cap 4, said upper section preferably being detachably connected to the lower section by cooperating screwthreaded portions 3 and 4' formed on said lower and upper sections. At its upper end the lower section 3 is provided with a chamber 5 formed therein, and the upper section 4 ispro-vided with a chamber 6 which, when the upper section or cap 4 is in place on the lower section 3, cooperates with the chamber 5 to provide a single chamber. The upper portion 4 of the bob I is provided with an upwardly extended portion I through which an opening 8 is formed longitudinally thereof, said opening being of enlarged diameter at its upper end as indicated at 8', and this enlarged portion being screw-threaded as seen in Figs. 1 and 2. The supporting cord 2 of the plumb bob is extended through the opening 8-8, and 9 designates a clamping element which is located Within the portion 8 of said opening. The clamping element 9 is formed of spring metal and comprises anV expansible split ring I0 with which a pair of oppositely disposed, upwardly extended arms II are associated. The arms Il at their upper ends are provided with substantially parallel portions, and the lower portions of said arms are inclined as shown in Fig. 1, said arms being formed integral with the split ring I0 at its upper edge. I2 designates a screw-threaded plug which is screwed into the screw-threaded portion 8 of the opening 8, the lower edge of said plug being adapted to contact with the inclined portions of the arms II when the plug I2 has been screwed inwardly into the portion 8 of the opening 8 a sufficient distance.

The supporting cord 2 passes between the upper, parallel end portions of the arms Il, and when it is desired to clamp said supporting cord so as to prevent movement thereof with respect to the bob I, the plug I2 is screwed downwardly into the opening 8. This will draw the upper ends of the arms II toward each other in a manner to tightly grip the supporting cord, whereby movement of said supporting cord relative to the bob is prevented. The arms Il are possessed of sufficient resiliency to cause said arms to move away from each other when the lower portion of the plug I2 is moved upwardly, thus permitting free movement of the supporting cord between said arms.

At the upper wall of the chamber 5 within the upper section or cap 4 is a screw-threaded projection I3 through which the opening 8 passes, and I4 designates an inverted U-shaped frame which isprovided with a screw-threaded opening I 4 in its upper wall, which receives the screwthreaded extension referred to so as to support the U-shaped frame in the chambers 5-6 within the bob I. The U-shaped frame I4 is possess-ed of sufcient spring or resiliency so that the downwardly extended legs of said frame may be moved outwardly from their normal positions, as illustrated in Fig. 2, and these downwardly extended legs support the cord-winding mechanism C of my improved plumb bob.

The cord-winding mechanism C of the improved plumb bob includes a reel I5, which is in the form of an element having an annular wall I6 and a rear Wall I1, said annular Wall being provided with annular outstanding iianges I8 between which the supporting cord is wound on the outer face of the annular wall. The reel I5, when considered apart from the mechanism associated therewith, is open at the side opposite to the side thereof at which the wall I 1 is situated, and said reel is provided with a centrally located extension 20 which is formed integral with the wall I'I and extends therefrom toward the opposite, open side of the reel. The extension 2S terminates short of the outer face of the reel at the side thereof opposite to the side at whichthe wall I'I is located, as shown in Fig. 2, and this extension is provided with an elongated opening 2I formed longitudinally thereof in which the inner portion of a short shaft 22 is disposed. The short shaft 22 has gear teeth formed thereon providing a pinion 23, portions of the shaft 22 being formed at opposite sides of said pinion, and the inner portion of said shaft is driven into the opening 2l to provide a drive t, whereby said shaft moves with the reel I5.

Located within the reel l5 is a spring barrel 24 which comprises an outer annular wall 25 arranged in contact with the inner face of the annular wall I6 of the reel I5, and a rear wall 26 arranged in contact with the inner face of the end wall Il of said reel. The spring barrel includes alsdan integral sleeve portion 2l which is located centrally of the spring barrel and extends inwardly from the wallY 26 thereof. sleeve portion`2'l is arranged to embrace the extension 23 of the reel as shown clearly in Fig. 2,

vsaid sleeve portion 21 and said extension 26 terminating in coincidence with each other.

28 designates a spring arbor which is in the fform of a cylinder which embraces the sleeve portionZI and extension 29 of the spring barrel and reel, respectively. At its outer end the cylindrical spring arbor`28 is partially closed, as

indicated at 2S' inFigs. 1 and 7, and said outer end of the arbor is partially cut away as indicated at 29 in Fig. '7, so as to `provide the arbor with an outer end which is substantiallyY semicircular in shape and of reduced diameter in one direction. The flat top faceLB of the outer end portion of the arbor28 is provided by cutting the outer end portion of the arbor .parallel with its l axis, and this at face 3) is joined by a flat face 3| which is extended at a substantial right angle to theiface 3l). The opening in the arbor which results from cutting same as indicated exposes the interior of the arbor, and the upper portion of the .pinion 23 already referred to herein is presented'at said opening. The outer portion of the short shaft 22 is journaled in an aperture formed in the outer end of the spring arbor 28, and @said substantially semicircular end portion ofthe arbor is extended into a correspondingly shaped aperture in the adjacent leg of the frame I4, whereby said arbor is prevented from rotating.

Arranged within the spring barrel of the cordwinding mechanism immediately adjacent. to the outer, .open end thereof is aniinternal gear` 32 (Figs. 2 and 3); said internal gear being fixed to and rotatable with the spring barrel 24. IThe outer end of the spring barrel isclosed by a plate 33 which rotatably supports an intermediate pinion 34. The intermediate pinion 34 meshes with the internal gear 32 and with the pinion 23, whereby motion is transmitted from vone of the gears 32-23 to the other thereof. VThe plate 33 is of varying thicknesses, said plate being relatively thin at its upper portion where the intermediate gear 34 is located and being thicker at its lower portion, the thickness of said plate at v its lower portion being approximately the same as the combined thicknesses of the upper plate portion and theintermediate gear. The plate 33 is of the approximate diameter ofthe interior of the reel I5, asshown in Fig. 2, and this plate is provided with an aperture 35 of theshape -and tion of the spring 36.

The

. 31 (Fig. 4) which is carried by said spring barrel and extends through an aperture in the end por- The opposite end of the helical spring 36 is fastened to the spring arbor 28 and engages said spring arbor in the manner shown-clearly in Fig. 4. The helical spring is shaped to provide an inner circle 40. A rivet or other fastening device 42 is extended through a portion of the spring comprising the inner circle and into an opening 42 in the spring arbor 28, whereby said spring portions are held in their proper positions. When the spring is being wound up, as when the supporting cord is pulled out the tendency is for the end portion of the spring to'move in the direction suggested by the arrow in Fig. 4.

' In the Ause of my improved plumb bob, out- .'ward movement of the supporting cord results,

through the operation of the cooperating gears,

Vin the springbarrel being rotated in the oppo-.g Vsite direction to the direction of rotation of the reel, whereby the helical spring is wound up, and when the cord is released the spring will rotate the reel to rewind Vsaid cord. If it should be desired to clamp the cordv to prevent movementg35 thereof with respect tothe bob, this may be accomplished by screwing the plug I2'downwardly,

- as alreadyexplained, to draw the clamping arms II together to the cord-clamping position.

An important feature of the' invention resides; in the fact that the entire cord-winding mechanism of my improved plumb bob is in the form of aunitwhich is conveniently detachable from the bob, it being necessary to merely unscrew the upper section or cap 4 fromthe lower section ofv the bob, whereuponthe cord-winding mechanism may be unscrewed from the screw-threaded extension'l3 `of said upper section or cap. The

Vcord-winding unit may then be taken apart by springing the'legs of the'U-shaped frame apart to free thespringarbor 28 from the apertures in-said legs in which it is normally disposed. The various parts of the cord-winding mechanism may thenY be lifted out of place, as no fas- -tening devices are employed to secure said parts together. To remove the helical spring it is only -necessary to disengage the outer end of said Y spring from the `pin V37, when said spring may be lifted out. When the cord-winding mechanism-is assembled, as shownV in Fig. 2, the lower ends vof the legs of the U-shaped frame VI4 contact with the curvedbottom wall of the chamvber 5,' whereby said legs are prevented from spreading.

Thecord 2'is attached at its inner-end to the mreel in the manner illustrated in Fig. 6; that is to say, one ofthe annular flanges I8 is provided with a pair-of slots I8' through which the cord .is passed inthe manner illustrated. By so at- Ltaching thecord to the reel the knot 2 is located Vvat the inside of the reel, where it will not inter- -ferewithfree rotation of the reel.

' I claim: Y In a spring windngireel, a hollow winding element, ancoil springA and .spring case therein, a.'

hollow spring arbor secured to the inner end secured to the hollow Winding element, and a of the spring, the outer end of the spring being gear train operable by said winding pinion reconnected to the case, a rotatable member exsponsive to rotation of the Winding element for tending internally of the arbor, a winding pinrotation of the spring case.

ion carried by said rotatable member, said member and pinion being co-axial with and rotatively EUGENE S. BUSH.

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