US802162A - Plumb-level. - Google Patents

Description

No. 802,162.- PATENTED 001'. 17, 1905. W. H. GRAY.

PLUMB LEVEL.

APPLICATION FILED MAR-151905- UNITED STATES PATENT OFFICE.

PLUMB-LEVEL.

Specification of Letters Patent.

Patented Oct. 17, 1905.

Application filed March 15, 1905- $erial No. 250,139.

To all whom it may concern:

Be itknown that LVVILLIAH H. GRAY, a citi- Zen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Plumb-Levels, of which the following is a specification.

My invention relates to plumb-levels; and its object is to provide a mechanism therefor that is highly sensitive and quickly responsive to variations.

Another and particular object of the invention is to provide a mechanism which will materially multiply in the pointer any movement of the actuating Weight or bob, so that even a slight variation in the position of the level will move the pointer or pointers to a plainlyperceptible extent; and the invention consists in the novel construction and arrangement of parts hereinafter described, and particularly pointed out in the claims.

In the drawings, Figure 1 is a transverse section through the cylindrical case and the mechanism therein. Fig. 2 is a face view, plates being removed. Fig. 3 is aview of one face, showing front plate and a portion of its adjacent back plate. Fig. 4 is a perspective view of the plumb-bob or actuating-weight. Fig. 5 is a perspective view of the casingshell minus the end plates. Fig. 6 is adetail view of the stationary or gage pointer. Fig. 7 is a perspective view of the oscillatingpointer frame; and Fig. 8 is a perspective view of the complete level, including the stock.

Referring to the drawings, 2 represents the usual form of stock, constructed in any suitable design and of any preferred material, usually wood. Through the stock is out a circular recess for the cylindrical shell 3, which is open at the ends and has aperipheral sightopening 4, as well as openings 5 5 for a supporting spindle 6, carrying the weight or bob 7. The latter has a hook or eye 8 engaging the spindle 6. v In the lower part of the bob 7 is formed a head or ridge 9, extending across the lower face of the bob. This bead is bored for a bar having projecting ends 10 10, adapted to engage oblong openings 11 11 in the pointer-frame 12. The latter is fulcrumed upon a fulcrum rod or axis 13, supported in suitable openings or otherwise in face-plates 1 1'and'15, closing the ends of the shell 3. mental openings 1A In said face-plates are cut segand 15, through which a pointers are made integral v12 to insure synchronous movements.

scale 16 on each of rear plates 17 18 may be seen. These plates are placed sufficient distances from the adjacent face-plates to make a space 19 between plates 14 and 17 and a space 20 between plates 15 and 18. A laterally-curved slot 21 is cut through the bob 7 for the fulcrum rod or bar 13 to permit the required swinging movement of the bob. Openings for said rod are also provided in the back plates 17 18, also openings 22 23 for, respectively, the pointers 25 24. These with the frame As shown, this frame consists of the horizontal cross-bar 26 and vertical arms 27 and 28, on which are formed apertured bosses 29 and 30, constituting bearings for the fulcrum-rod 13. The face and back plates may be secured to the shell 3 in any suitable manner; but I have shown its ends counterbored or rabbeted at 31, which provides shoulders 32 33, engaging the edges of plates 17 and 18, respectively. The face and rear plates may be spaced apart by rings (represented in section at 34: and 35, Fig. 1) open at the openings 14: and 15', or the rings may be made continuous past said openings, if preferred. The plates 14: 15 17 18 may be brazed, soldered, or secured in any other suitable manner to the shell 3.

In Fig. 6 is shown an auxiliary pointer or indicator stamped out of a piece of sheet metal to provide a spur or finger 36, bent substantially at right angles to the body 'portion 37 in which is a slot 38, engaging a'screw 39,having threaded engagement with a threaded hole 40 in the shell 3. The body portion 37 may be made of spring metal and bent elastically into position against the curved surface of the shell, so that it may have sufficient frictional engagement with said shell and thejhead of screw 39 to prevent its accidental movement. When a structure surface or structure itself is to be built with a certain degree of inclination, the pointer 36 may be set opposite a given point on the scale 16 and the level adjusted until the pointers 24. and 25 coincide with or are opposite the pointer 36.

The frame 12 is preferably constructed of light materialsuch as, for instance, aluminiumso that it will oscillate readily or promptly under comparatively slight leverage, and in order to obtain the greatest possible extent of movement of the pointers 24: and 25 for a given movement of the bob 7 the distance between the axis of rotation of the frame 12 and the arc of rotation of spindle ends 10 is made a comparatively small fractional part of the total length of radius between said axis and the pointers 24 and 25. By pivoting the pointer-frame independently of the hob, and applying the power of the latter at its longest arc of rotation and to the frame near its axis of rotation, the latters movement may be multiplied to any extent necessary for a distinctly perceptible movement of the pointers 24 and 25, where the inclination of the level is very slight. Plumb-levels having the pointers attached to the bob are practically useless for the purpose of indicating anything but pronounced variations. If a level-stock is two feet long, an elevation or depression of one 1 end thereof of one-fourth inch would swing a weight three inches in height only one thirtysecond of an inch at its lower end if pivoted at its upper end. The maximum movement that may be imparted to a pointer when same is on the Weight and confined within substantially the same space as the weight is there fore only one-eighth of the sweep or movement at the end of the two-foot stock (or one thirty-second part of an inch) if the movement at the end of the latter is one-fourth of an inch. If the same weight and pointer are pivoted intermediate of their extreme ends, or midway, a one-quarter-inch movement at the end of the stock will produce only a sixtyfourth part of an inch movement in the pointer. In either event the pointer movement is imperceptible for all practical purposes. Instead of imparting a decreased movement to the pointer the present invention produces a greater movement in the pointer than at the end of the stock. If the pointer-arm is three inches in length and same is fulcrumed onefourth of an inch from its lower end or the point at which leverage is applied to the arm, the one thirty-second inch movement referred to above will be increased in pointers 24 and 25 to about eleven thirty-seconds of an inch or three thirty-seconds in excess of the movement at the end of the stock. One-sixteenth part of an inch is plainly perceptible to the average human eye, and a movement to that extent in the pointers 24 and 25 therefore indicates distinctly the slight inclination from a level line of about one foot rise or depression for a distance of about ninety feet. Now if the builder, knowing the percentage of grade or inclination that must be maintained, desires to set the level accordingly he will move the pointer 36 to the proper point on the scale and adjust the structure or level so as to bring the pointers 24: and 25 in line with the pointer 36. As stated above, the substantial movement of one-sixteenth of an inch will indicate an incline or grade only slightly over one per cent. With an ordinary combination bob and indicator or pointer pivoted centrally no ordinary incline could be perceptibly recorded at the pointer, and a movement of one-sixteenth of an inch would require an inclination of probably not less than ten per cent.

As may be noted by reference to Figs. 1 and 8, the pointers can be seen from both sides and the top of the level, the stock 2 being provided with an opening I, which registers with the opening 4 in the shell 3.

The openings 14 and 15 may be covered with glass in the usual manner, and as the only portions of the case which require a glass or transparent portion are the comparatively small spots opposite the indicatorpoints and scales 16 the liability of breakage is greatly reduced, and the mechanism is well protected by the metallic case comprising shell 3 and face-plates 14 and 15., all preferably constructed out of brass.

Numerous modifications may be made in the details of construction without departing from the spirit of my invention, and

I claim as new and desire to secure by Letters Patent 1. In a plumb-level, the combination with a recessed weigh t, of a pointer-frame pivoted to said weight, said frame being arranged around said weight and fulcrumed upon a rod passing through the recess in said weight, said Weight and frame being arranged to multiply in the former a given movement in the latter and to indicate said movement at opposite sides and the top of said weight.

2. In a plumb-level, the combination with a recessed stock, of a shell 3, a weight or bob arranged to be concealed within said shell, dials arranged on opposite sides of said weight, a frame having pointers arranged to move over the outer faces of both of said dials, said frame arranged around said weight and consisting of a single and comparatively rigid member to insure synchronous movements of its pointers, said Weight and frame being mounted and pivoted together so as to multiply in the pointers a given movement of the weight.

3. In a plumb-level, the combination with a recessed stock, of a casing, a swing-bob or weight, dials in the ends and an opening in the top of said casing, said dials arranged to conceal otherwise exposed portions of said weight, a fulcrumed frame pivoted to and passing partly around said weight, said frame having pointers which cooperate synchronously with the faces of all of said dials.

4. In a plumb-level, the combination, with a recessed stock, of a plurality of dials, an oscillating frame having arms the free ends of which constitute pointers, an oscillating weight pivoted to said arms at substantially its maximum arc of swing, said arms being fulcrumed substantially in the plane of the cord of said maximum arc, said weight being confined between the dials while said arms are arranged to cooperate with the outer faces of said dials.

5. In a plumb-level, the combination with a recessed stock, of a shell, a recessed weight suspended from the upper part of said shell, dials at the ends of' said shell and a sightopening arranged at right angles to said dials, a frame pivoted to said weight and fulcrumed upon a rod passing through the recess in said weight, said frame consisting of a single member the ends of which constitute pointers which cooperate with said dials and move opposite said opening.

6. In a plumb-level, the combination with a stock, of a casing having a sight-opening, dials in the vertical sides of said casing, a recessed actuating-weight pivoted in the top of said casing, a pointer-frame cooperating with said dials and sight-opening, and a fulcrumrod for said frame extending through said recess in said weight, said weight and pointerframe being pivoted together in a plane below the plane of said fulcrum-rod.

7. In a plumb-level, in combination, a shell 3 having front plates 14 and 15 with dialopenings therein and sight-opening 4, a dial 16 opposite each of said openings, the pointerframe 12 cooperating with said dials and opening 4, and the weight 7 arranged to swing said frame so that the upper or pointer ends thereof swing several times the distance through which said weight itself swings.

8. In a plumb-level, in combination, a shell 3 having front plates 14 and 15, with dialopenings 14 and 15, and back plates 17 and 18 carrying scales 16, said shell having also a sight-opening 4, the frame 12 having arms 27 and 28 and horizontalpointers 24 and 25, the weight 7 pivoted substantially at the arcs of swing of pointers 24, 25, said Weight having the bead 9 and recess 21, and said frame fulcrumed near the arc of maximum swing of said weight 7, on the fulcrum-rod 13 extending through said recess in said weight.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

WILLIAM H. GRAY. .l/Vitnesses:

FRED L. KoEHLER, RoB'r. KLOTZ.

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