US2013957A - Weighing scale - Google Patents

Description

Sept. 10, 1935. H. o. HEM 2,013,957

WEIGHING SCALE Filed Dec. 14, 1951 A TTORNEY.

Patented Sept. 10, 1935 UNITED STATEh PTET QFFICE WEIGHING SCALE Application December 14, 1931, Serial No. 580,892

6 Claims.

This invention relates to weighing machines which are employed for weighing the ingredients used in making concretejlparticularly those which are adapted to compensate for the surface moisture in sand and in other aggregates. It has been established by research and experiment that the maximum strength of a finished concrete structure can only be obtained when sand, coarse aggregate, cement and water are mixed together in proper proportions. Sand, gravel and crushed stone generally contain a certain amount of water, especially after having been stored in the open. It is obvious, therefore, when 100 pounds of sand containing five percent of water is weighed, the amount of surface dry sand amounts to only pounds, the other 5 pounds being water and it will be readily seen that more sand must be added to conform to the amount specified if the formula is based on surface dry sand or sand carrying less moisture. An excess of water de creases the strength of concrete, therefore, the more moisture in the sand, the less water should be added. Additional sand cannot be added haphazardly as too little water also decreases the strength.

The present invention has for its principal object the provision of means for determining the proportion of surface dry sand or other aggregates in a load when the percentage of moisture contained therein is known.

Another object of the invention is the provision of improved means which automatically determine a certain fraction of a total load on the load receiver, particularly that fraction which represents the equivalent by weight of surface dry sand in the total load.

A further object is the provision of improved means which. eliminate the necessity for arithmetical calculations or engineering skill on the part of the operator in determining the proper amounts of surface dry sand or other aggregates.

Still another object is the provision of improved means whereby the travel of a load counterbalancing poise on a beam is changed proportionally to the moisture content of the aggregate.

A further object is the provision of means whereby the percentage of additional load to compensate for the moisture is indicated in terms of weight.

A still further object is the provision of improved means for varying the location of an index on a load counterbalancing poise to cause percentual additions to the load automatically.

These and other objects and advantages will be apparent from the following description in which reference is had to the accompanying drawing in which similar reference numerals designate similar parts throughout the several views.

In the drawing:-

Figure I a front elevational view of a device embodying the invention.

Figure II is a side elevational view thereof.

Figure III is an enlarged detailed view of a load counterbalancing beam and poise.

Figure IV is an enlarged sectional view through the beam and poise substantially along the line IV-IV of Figure III; and

Figure V is an end elevation of the beam and poise.

Referring to the drawing in detail, the invention is shown attached to a type of scale which is well known and I will not describe it in greater detail than is necessary to thoroughly explain the invention. A base I mounted on wheels 2 contains a load supporting lever system 3 which in turn supports a load receiving platform 4. The base i is provided with .a rearward extension 5 upon which a column 6 is fastened. Extending upwardly, within the column d, and pivotally engaging the lever system with its lower end is a connecting rod 1, the upper end of which engages a tare beam lever 8. This tare beam lever is provided with a series of pivots, one of which engages a short con necting rod 9 which connects the tare beam lever 8 with a motion multiplying lever ill which is fulcrumed at l I to a substantially watch-case-shaped housing l2 surmounting the column 6. A nose pivot stationed in the lever 10 engages a stirrup suspended by means of flexible ribbons I3 from the load counterbalancing pendulum mechanism It. Operatively connected to the pendulum mechanism is an indicating hand [5 which is adapted to be angularly movable over an indicia bearing chart It. The angle traversed is in proportion to the weight of a load on the platform 4 and thus indicia may be provided on the face of the chart H5 which accurately indicate the weight.

Secured to the ends of the tare beam lever B are brackets H to which tare beams 18 and 59 are fastened. These beams have mounted thereon poises Ell and M respectively. As the construction of all beams and poises is similar, I will describe one only. Pivoted at the end to the rear of the beam I8 is a sine bar 23 whose other end terminates in a loop-like structure M which straddles the beam !8. This loop-like end is also provided with an arcuate slot 25 through which a thumb screw 26 extends, which is threaded into the beam I8 and serves to retain the bar 23 at any desired angle with reference to the horizontal axis of the beam Hi. This slot 25 also determines the limits of angular adjustment of the bar 23. Fastened to the beam I8 is an index plate 2! bearing a series of indicia 28, for co-operation with a mark 29 engraved or etched, in the member 24. These indicia 28 represent percentages of the total capacity of the beam l8 as indicated by the indicia 29. The poise 20 which is slidably mounted on the beam l8 consists of two body members as and 31 which are fastened to each other by the screws 32. The inner edges of the body members 30 and 3| are cut away to receive the beam l9 and the thereto attached bar 23. Mounted for vertical movement within the poise body is a sliding barlike member 33 which, for a portion of its length, is provided with teeth 34 which engage the teeth of a pinion 35 which is fastened to a shaft 36 fulcrumed in apertures in the bosses 31 and 38 of the body members 30 and 3|. To the opposite end of the shaft 36 a pinion 39 is fastened, the teeth of which engage the teeth of a horizontally disposed rack 40. This rack has also fastened to it an upwardly extending tongue-like member 4! which is provided with an index line 42. The tongue-like member 4| is disposed immediately in front of the beam l8 and the index line 42 is adapted to co-operate with the graduations 29 on the beam and with the series of indicia 43 which are stamped or etched on an inwardly extending inclining face 44 of the sight opening 45. The in-- dicia 43 represent weight in pounds and indicate the weight of the percentage of surface moisture clinging to the aggregate being weighed. Rotatably situated in a fragmentary circular cut-out of the vertically movable rack 33 is a cylindrical member 46, one face of which is provided with a milled slot which straddles the sine bar 23. The mounting of the cylindrical member in the rack 33 is such that it rotates about its axis when the sine bar 23 is angularly adjusted and the poise 20 shifted permitting the abutments, formed by the milled slot, to freely contact the bar 23 during the movement of the poise.

When it is desired to weigh out sand or other aggregates for concrete mix and to compensate for the adhering surface moisture, the operation of the device is as follows: assuming the formula requires I00 pounds of surface dry sand and it has been determined by any of the well known methods that the available sand contains five percent of surface moisture, the thumb screw 2!; is loosened and the bar 23 is adjusted so that the index line 29 coincides with the five percent graduation of the index plate 21 (this position is indicated by the dotted lines A in Figure III). The poise 20 is now moved along the beam IS, the cylindrical member 46 which straddles the bar 23 follows it and the member 33 moves downwardly, thereby turning the pinion 35 with which it meshes. This pinion being fastened to the shaft 36, revolves the pinion 39 and this in turn moves the horizontally disposed rack 40 with the thereto tongue-like member 4| inwardly.

The angle of the sine bar 23 and the movements of the racks, plnions and the tongue-like member fastened to one of the racks, are calculated so that the final position of the index line 42 requires the center of mass of the poise and ports carried thereby to be shifted on the beam an additional five percent of the distance between the zero and the 100 pound mark, although the index line 42 registers with the 100 pound mark on the beam IS. The change in position of center of mass resulting from movement of the rack bar 43 is taken into consideration in determining the ratio of movement of the index 4| along the raduations 29 to movement along the indicia 43. To balance the scale, an additional. five percent of surface moist aggregate must be placed on the platform; in this example, 5 pounds which represent the moisture in the load, thus there are exactly 100 pounds of dry aggregate and 5 pounds of water on the platform. This amount of water is plainly indicated by the index line 4?. on the series of indicia 43 and the operator is enabled to deduct this amount from the amount of water required, by the formula, for each batch.

The embodiment of my invention herein shown and described is to be regarded as illustrative only, and it is to be understood that the invention is susceptible to variation, modification and change within the spirit and scope of the subjoined claims.

Having described my invention, I claim:

I. In a device of the class described, in combination, a load-offsetting beam provided with graduations to indicate the amount of a. com inodity ingredient, a poise provided with an index co-operating with graduations, means on said poise and beam for varying the travel of the center of mass of poise necessary to bring the index into registration with a given graduation on said beam, anr means for setting said means for varying the travel of the center of mass of said poise in accordance with the relative amount of second ingredient of such commodity.

2. a device of the class de. cribed, in combination, a load-offsetting beam and poise, a series of indicia on said beam, an index movably secured to said poise for co-operation with said series of indicia, and manually settable means for causing relative movement of said index upon movement of said poise, said manually settable means including means for quantitatively indicating the movement of said index relative to the movement of said poise.

3. In a device of the class described, in combination, a. load-offsetting beam and poise, a series of indicia on said beam to indicate quantities of an ingredient of a load, an index movably secured to said poise for co-operation with said series of indicia, and manually settable means for causing relative movement of said index upon movement of said poise, said manually settable means including means for quantitatively indicating the movement of said index relative to the movement of said poise in terms of percentage of the weight of said ingredient.

4. In a device of the class described, in combination, a load-offsetting beam, at load-oifsetting poise mounted thereon, a sine bar mounted on said beam, means for varying the angular position of said sine bar, an index movably mounted on said poise, indicia on said beam cooperating with said index, and means on said poise co-opcrating with said sine bar for varying the extent of movement of the center of mass of said poise required to move said index into registration with certain of said indicia.

5. In a device of the class described, in combination, a relatively movable load-offsetting beam and poise, an angularly adjustable bar mounted on said beam, a rack and pinion carried by said poise, means slidably and pivotally connecting said rack to said angularly adjustable bar, a second rack and pinion carried by said poise, means operatively connecting said pinions, a movable index attached to said second rack, and a series of indicia on said beam adapted to gates in terms of fractions of surface dry Weights thereof, manually settable means adapted to be selectively set in accordance with said surface moisture weight indications, and. means controlled by said manually settable means for varying the movement of said load-counterbalancing' means required to move said surface dry weight indi-- cating means to indicate any certain surface dry weight.

HALVOR. O. HEM.

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