US1576948A - Scale - Google Patents

Description

March 16 1926.

H. M. CAMERON SCALE Filed August 18, 1921 3 Sheets-Sheet 1 1,576,948 H. M. CAMERON SCALE March 16 1926.

Fild August 18, 1921 sfheets-sheet 2' March 16,1926. 1,576,948

H. M. CAMERON SCALE I Filed August 18, 1921 s Sheets-Sheet 5 .J 2/ kas w 47 I5 /9 V 441 V A Patented Mar. 16, 1926.

UNITED STATES PATENT OFFICE.

HUGH M. CAMERON, OF NEWARK, NEW JERSEY, ASSIGNOR TO JOHN CHATILLON & SONS, OF NEW YORK, N. Y.," A CORPORATION OF NEW YORK.

SCALE.

Application filed August 18, 1921. Serial No. 498,288.

To all whom it my'concem;

Be it known that I, HUGH M. CAMERON,

a citizen of the United States, and a resident of Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Scales, of which the following is a specification.

This invention relates to scales, and more particularly to spring scales in which the load is applied and the spring is secured, to a tiltable lever, and the movement of the lever is communicated to a dial pointer. Such scales have many advantages, both in construction and in operation, over other types of scales, but they present a difficulty in the way of employing equally spaced dial graduations for equal increments of load, due to the change of length of the moment arm .-as the lever tilts. Thus, if, on a pivoted lever, the load is applied at a higher level than the pivot, its moment arm will lengthen as the lever tilts, so that with increasing loads the readings will increase faster in proportion than the respective loads. This effect is known in the art "as fastness of the balance, and the reverse is known as slowness.

The object of the invention is to produce a compact scale having equally spaced dial graduations. By utilizing in a" novel manner the features of the above-mentioned type of scale, I am enabled to secure a muchgreater degree of compactness than hitherto has been possible in scales of-this or any other type. Equally spread graduations are obtained by employing a secondary spring, so tensioned with respect to the primary spring, and so positioned on the lever, as to counteract the tendency to fastness.

With these and other objects in view, I have devised the apparatus embodying my invention, as described, in the following specification and illustrated in the accompanying drawings, of which- Figure l is a plan view of the scale;

Figure 2 is a detail plan view of the pointer actuating mechanism;

Figure 3 is a vertical longitudinal section of the scale; Figure '4 is an enlargement, partly in section, of certain parts shown in Figure 3;

Figure 5 is an end elevation of the parts shown in Figure4; Figure 6 is an end elevation, partly in section, of the parts shown in Figure 5; and

Figure 7 is a plan view of the parts shown in Figures 4, 5 and 6.

1 represents the frame of the scale, platform 2 of which is supported on knife edges 3 and 4 of multiplying levers 5 and 6 respectively. Levers 6 is fulcrumed on knife edge 7 bearing onlink 8, the latter being suspended from frame 1. Lever 5 is fulcrumed on knife edge 9 bearing on link 10, suspended from frame 1. The free end of lever 5 carries knife edge 11 which bears on link 12 suspended from knife edge 13 carried on lever 6. Knife edges 11 and 13 should be midway between knife edges'3 and 4, and the distance between knife edges 3 and 9 should be equal to the distance. between knife edges 4 and 7. The advantage of this arrangement resides in the fact that the load may be placed anywhere on platform 2 with the same effect as if it were suspended from knife edge 4, and the need of accurate centering of the load is avoided' The free end of lever 6 carries knife edge 14.

Lever 15 is supported on a pair of conical bearings 16 and 17, resting pivotally in con-' ical cup bearings 18 and 19 respectively, With only point contact. Cup bearings 18 and 19 are supported by block 20 on frame 1. Securely fixed on lever 15 is loadsupporting arm 21, carrying conical bearing 22. Yoke 23 carries conical cup bearing 24, and is supported thereby with point contact on bearing 22. Hook 25 is suspended from yoke 23, and carries the load transmitted by lever 6, knife edge 14 of the latter resting in hook 25. It will be noted that the point of application of the load on lever 15, that is, the point of contact between bearings 22 and 24, is above the level of the pivot point of the lever, or the points of contact between bearings 16 and 18, and bearings 17 and 19 respectively. Also securely fixed on lever '15 is spring arm 26, which, for a horizontal dial scale, preferably extends vertically upward at the no-load position of balance 15. Hinged or pivotally connected to the upper end of arm 6 is a horizontally dis-- posed rack 27, to the free end of which is secured primary spring or load resisting means 28. The latter is secured to frame 1 by adjusting screw 29, having a pin 30 in slot 31 of frame 1 to prevent turn-in and being adjusted by winged nut 32. pring 28 is disposed on the proper side of arm 26 to oppose the turning moment of the load transmitted through bearing 22.

Carried in bearings 33 and 34 is vertically disposed dial pointer shaft 35, having inion 36 integral therewith or securely fixed thereto. Rack 27 meshes with and actuates pinion 36 and thereby rotates pointer 37 secured to the upper end of shaft 35. Guide 47 holds rack 27 positively in mesh with pinion 36. Horizontal dial 38, with equally spaced graduations, is disposed concentrically of shaft 35 and is supported by frame 1, being covered by the usual glass plate 39.

Integral with lever 15 is column 40, extending parallel to spring arm 26. Horizontal bar 41 is, clamped in slot 42 of column 40 by bolt 43 and nut 44, and is longitudinally movable in slot 42 when unclamped for adjustment purposes. Vertically disposed secondary load resisting means or spring 45 is secured at one end to the free end of bar 41, the opposite end of spring 45 being slidably retained by fastener 46 to frame 1, thus permitting spring 45 to assume normal position for various ad ustments of bar 41. Spring 45 and bar 41 are disposed on the roper side of lever 15 to oppose the turmng moment of the load. Spring 45 is preferably very much weaker than spring 28.

In operation, the load to be weighed 1s placed on platform 2. The weight is transmitted into lever 6 exactly as if it were suspended directly from knife edge 4, as

previously explained, and is transmitted to load sup ort of lever 15 in the ratio of the distance etween knife edges 4 and 7 to the distance between knife edges 14 and 7. A

further multiplying effect of spring 28 is obtained by the difference in len ths of arms 21 and 26 respectively, thus emp' oying lever 15 for an additional function. As lever 15 tilts, springs 28 and 45 stretch, and their tension increases sufficiently. to counterbalance the turning moment of the load, and as pointer 37 comes to rest the reading may be taken. The equally spaced graduations of'dial 38 are calibrated to readin suitable units of weight.

Itwill be observed that the dial reading will be. directly proportional to the elongation of spring 28, and that both dialreadmg and elongation, as well as the resisting moment of sprin 28 about the pivot oint of balance 15, wi be directly proportional to the sine of the angle of tilt. As the point of application of the load, i. e., thepoint of contact between bearings 22 and'24, is above the level-of the pivot point of'lever 15, the line joining said points, for the no-load position of the lever, will incline at a certain angle above'the horizontal; and the moment arm, or effective lever arm of the pointer.

actuating forces, means connecte load for any position of .the lever 15, will not I sating spring 45, and equating moments, we,

find that the load multiplied by said cosine is directly proportional to the elongation of spring 28, and hence to the dial reading. As the angle of tilt increases, the cosine-of the angle of inclination minus the angle of tilt will increase (being the cosine of a diminishing angle), but at a diminishing rate of increase. Hence, as the weight is increased, the dial reading will increase more in proportion, but at a diminishing rate of increase. If now we consider the effect of spring45, we shall observe that it tends to retard the movement of the dial pointer. Without going into the mathematical analysis, it may be stated that with spring 45 arranged as shown and above described, resisting moment of said sprin will vary, with variation of load, in such manner as exactly (or with such accuracy as to render the error in practice inappreciable) to overcome the above eziplamed tendency to fastness on the part of the dial It will further be noted that the present design may be modified by positioning spring 45 and securing the same to lever 15 in a great variety of ways other than shown, provided it be disposed at a suitable angle to the'radius drawn from the pivot point of lever'15 to the of spring 45 thereon.

One of the advantages of the above described scale resides in its compactness, the scale dial being horizontal. However, such a scale: may be constructed in a number of diflferent ways. Thus the invention, which resides in the underlying principle rather than in any particular form or distrbution about its pivot whereby the moment armof said forces about the lever'pivot changes with tilting of the lever, a load resistin means connected to said lever to op ose sai to said. lever for applying forces thereto substantially proportional to changes in length-of point of attachment Y said moment arm ,and in a direction to compensate for such changes, weight indi-- cat ng means for the load on said support,

and an actuating mechanism connecting said lever with said indicating means.

2. In a scale, the combination with a frame, of a lever pivoted on the frame, a load support connected to said lever, load resisting means also connected to said lever,

auxiliary means connected to said lever at anangle to saidload resisting means to compensate for changes in length of the moment arm of the load support about the lever pivot as the lever is tilted, a dial, a pointer, and actuating connections between said lever and point/er.

3. In a scale, the combination with a frame, of a lever pivoted on\the frame, a load support connected to the lever above the pivot so as to increase the moment arm of the load support about the lever pivot as said lever is tilted, load resisting means also connected to the lever, auxiliary load resisting means connected to said lever in such a manner as to compensate for increase in length of said moment arm, a dial, a pointer, and actuating connections between said lever and pointer.

4. In a scale, the combination with a frame, of a lever pivoted on the frame, a load support connected to said lever adjacent one end, load resisting means connected to the other end of the lever, auxiliary spring load resisting means connected to said lever and frame in such a manner as t-o'compensate, for changes in length of the moment arm of the load support about the lever pivot as the lever is tilted, a dial, a pointer, and actuating connections between sa'id lever and pointer.

. posing the i 5. A scale comprising a pivoted lever, a fixed support therefor, a load support so connected to said lever as to increase the moment arm of the load about the pivot oint of the lever as the latter is tilted therey, a spring secured to the lever and opposing the load, graduated weight indicating means having a movable indicating element'actuated by said lever, the travel of said element being proportional to the elongation of the spring, and adjustable means for counteracting the tendency to fastness of the scale due to the connection of the load support, thereby permitting equal spacing of the graduations for equal increments of load.

6. A scale comprising a pivoted lever, a fixed support therefor, a load support so connected to said lever as to increase the moment arm of the load about the pivot oint of the lever as the latter is tilted therey, a spring secured tothe lever and opoad, graduated weight indicatmg means having a movable indicating element actuated by said lever, the travel .of said element being proportional to the elongation ofthe sprin and a second spring so I positioned with respect to the pivot point of said lever, and so tensioned with respect to first said spring, as to counteract the tendency to fastness of the scale due to the connection of the load support, thereby permitting equal spacin of the graduations for equal increments of oad.

7. A scale comprising a pivoted lever, a fixed support therefor, a load sup ort so connected to said lever as to increasethe moment arm of the load about the pivot point of the lever as the latter is tilted thereby, a spring secured to the lever and opposing the load, raduated weight indicating means having a movable indicating element actuated by said lever, the travel of said element being proportional to the elongation of the spring, a second spring so positioned with respect to the pivot point of said lever, and so tensioned with respect to first said spring, as to counteract the tendency to fastness of the scale due to the connection of the load.

support, thereby permitting equal spacing of the graduations for equal increments of load, and means for adjusting said second sprlng.

8. A scale comprising a pivoted lever,.a fixed support therefor, a load support so connecte to said lever as to increase the moment arm of the load about the pivot point of the lever as the latter is tilted there; by, a springsecured to the lever and opposing the load, graduated weight indicating means having a movable indicating element actuated by said lever, the travel of said element being proportional to the elongation of the spring, a second spring so positioned with respect to the pivot point of said lever, and so tensioned with respect to firstsaid spring, as .to counteract the tendency to fastness of the scale due to the connection of the load support, thereby permitting equal spacing of the graduations for equal increments of load, and means for adjusting said second spring by varying the moment arm thereof on said lever.

9. In a scale, the combination with a frame, of a lever pivoted on the frame, a load support, connected to said lever adjacent one end, spring load resisting means also connected to the other end, auxiliary spring load resisting means connected to said 'lever'and frame and disposed at an angle to the radius drawn from the pivot Y 10. A scale comprising a. pivoted lever, a.

fixed support therefor, a load support so connected tosaid lever as to increase the moment arm of the load about the ivot point of the lever as the latter is tilted t ereby, a spring secured to said lever and opposing said load, a rack connected to said lever, guide means for said rack, a pinion actuated by said rack, graduated weight indicating means actuated by said pinion and means for counteracting the tendency to f astness of the scale due to the connection of the load support, thereby permitting equal spacing of the graduations on said indicating means for equal increments of load.

11. A scale comprising a pivoted lever, a fixed support therefor, a load support'so connected to said lever as to increase the moment arm of the load about the ivot point of the lever as the latter is tilted t ereby, a spring secured to the lever and opposing the load, graduated weight indicating means actuated by said lever and registering proportionately to the sine of the angle of tilt thereof, and means for counteracting the tendency to fastness of the scale due to the connection of the load support, thereby permitting equal spacing of the graduations on the indicating means for equal increments of load.

12. A scale comprising a pivotal lever having a load arm, a load support connected with said load arm, an opposing spring connected with the lever, a pointer and scale one of which is actuated by the lever, a supplemental spring relatively weak compared to the opposing spring arranged at an angle to the first spring and connected with the lever to substantially compensate for changes in length of the moment arm of the load with movement of the lever about its pivot, and actuating connections between said scale and pointer and said lever.

Signed at New York city, in the county of New York and State of New York, this 15th day of August A. D. 1921.

HUGH M. CAMERON.

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