US2045974A - Scale - Google Patents

Description

June 1936- E. J. vo PVEIN ET AL ,045,974

SCALE Filed Nov. 29, 1935 ORNEY UNITED STATES PATENT OFFICE SCALE Edward J. Von Pein, Endicott, and William N.

Gilbert, Binghamton, N. Y., assignors to International Business Machines Corporation, New York, N. Y., a corporation of New York Application November 29, 1935, Serial No. 51,996

'7 Claims.

This case relates to the counterbalancing and indicating mechanisms of Weighing scales.

The invention contemplates novel means for operating an indicator from a floating type of pendulum counterbalance.

The invention also contemplates novel for constraining an indicator-operating element to vertical, rectilinear movement.

means Other objects will appear from the following parts of the specification and from the drawing which shows the counterbalancing and indicating means in elevation.

Frame l carries spaced, vertical guide bars ll forming tracks for rollers l2, which are suspended by tapes |3 from the guide bars.

Rollers l2 carry pendulums 14, located in parallel, spaced,

planes to permit them to pass each other during a weighing operation, as indicated in dotted lines in the drawing.

Rigidly fastened to each pendulum roller I2 is a cam power sector l5, from which a ribbon l6 extends downwardly to be connected through a tie buckle H, to one end of an equalizer bar la. The two ribbons [6 are thus connected to the opposite ends of equalizer bar I8.

Connected to the center of bar I8 is a draft rod l9 which transmits the load force to the equalizer.

Between pendulums I4 is located a sectorshaped member 20, around the arcuate periphery of which the intermediate portion of a tape 2| is wound. The tape extends upwardly from opposite sides of member 20 to be fastened at opposite ends to the two pendulum rollers [2.

The tape is fastened intermediately to the central point of the arcuate peripheral portion of member 20.

Member 20 carries, at its center of curvature, a pivot pin 22 which freely pivotally mounts a bell crank lever 23, the Vertical arm of which forms the foot of a rack 24 and the horizontal arm of which is provided with a weight 25 to maintain the rack in mesh with a pinion 26. Pinion 26 is fixed to shaft 27 which carries load indicating pointer 28.

ing to the right.

When a load is applied to the scale, the force of the load is transmitted to draft rod [9 depresses equalizer bar l8.

which Through ribbons IE,

bar I8 when depressed rocks the opposite pendulums l4 upwardly and towards each other.

As the pendulums rock upwardly, their rollers 12 ride up on the track surfaces of bars ll, thus also causing the pendulums to be bodily moved upwardly. When rollers l2 ride up on bars II,

through tape 2|, they raise member 20, rack carrier 22 (including weight 25), rack 24, vertical link 30, and check levers 3| and 32. The weight of the parts thus raised by action of rollers [2 functions as additional load counterbalancemeans supplementing the counterbalance func-' tion of pendulums l4. As rack 24 rises it rotates pinion 26, its shaft 21, and load pointer 28. The pendulums and the other counterbalance means are moved until they counteract the load. When these parts come to equilibrium position, pointer 28 indicates the load.

Bar l8 factors the load force into two halves, one half transmitted to the left hand pendulum and the other half transmitted to the right hand pendulum. Each pendulum in turn supports half the weight of member 20 and the parts connected to the member. In order for this to be true throughout operation of, the scale, member 20 must remain during its rise, along a definite path mid-way between the pendulums, or in other words, the center of curvature of member 20 must be maintained along a line half-way between the pendulum rollers [2. Another reason for this is that if the member 20 moved nearer to one pendulum roller, or out of its predetermined central 30 path, then rack 24 would be inclined. As a result, rise of the rack would not rotate pinion 26 (and consequently load pointer 28) through the same increments as when the rack is moving parallel to said center line between the pendulum rollers. The scale is calibrated to indicate the load according to increments of movement of the rack when the rack is moving parallel to aforesaid center line and if the rack is in an inclined position with respect to this center line, the increments of movement of the rack will not provide the calibrated indications of load but will indicate less load than is actually on the scale.

Further, when the scale is out of level, all the parts thereof should tilt to corresponding extents. It is well known that the opposite pendulums will take positions corresponding to the tilt of the scale, one pendulum moving further than normal and the other less than normal. 0

Member 20 acts as an equalizer between the 5 pendulums. Thus, when one pendulum drops below its normal position for a given load and the other rises above such normal position, the member 20 will average up these movements and its center of curvature will remain at normal 55 height for the given load. This again is only true if the center of curvature of member 20 remains along the center line between the two pendulums. When the scale tilts, this center line also tilts to the same extent, and therefore member 20 must not be permitted to hang vertically when the scale tilts but must be constrained to depart from the true vertical in accordance with the tilt.

When the scale tilts, the rack will also tilt but since all the other parts of the scale including the pendulums are similarly tilted, the relation and interaction between the parts will remain the same as when the scale is level, and the calibrated load indications will be furnished by movement of the pointer.

For these several reasons, then, namely; to divide the weight of the member 20, and parts connected therewith, equally between the two pendulums; to maintain the rack 24 movable parallel to. the center line between the pendulums; and to permit the member 2a to equalize and average the movements of the two pendulums, the center of curvature of the member must be maintained along the center line between the pendulums. This is done by the check levers 3| and 32 acting through link 30.

These check levers are not parallel (as is usual with platform check linkages) but are non-parallel, extending in diverging directions. The check levers are of equal lengths, and their initial angles to the horizontal are the same. Thus, the check levers will move through equal angles for any given movement of the member 2!). Accordingly, thefree end of each check lever will cover an arc equal in length to the are through which the other check lever moves at its free end. Since the check levers extend in opposite directions from their pivots, their respective arcs of movement are opposite in curvature. Further, since the check levers diverge and are at the same side of the horizontal, the arcs of movement of the check levers are not only opposite in curvature but in a strict directional sense extend oppositely, whereas if the check levers were parallel throughout their movement, their arcs, though opposite in curvature, would in a directional sense extend in the same direction.

For the above reasons, the free ends of the check levers, throughout the range of the scale, will be at opposite sides of the center line between the pendulums except at the zero load point (indicated in full lines in the drawing) and at the maximum load point (indicated in phantom lines in the drawing) when the free ends of the check levers will be directly on aforesaid center line. Between the zero and maximum load points, the free ends of the check levers and therefore the upper and lower ends of connecting link 30 will be at opposite sides of the center line and-at equal distances from said center line. Therefore, the center point of link 30 will always remainon said center line.

Since member 2!) is connected by pivot pin 22 to the center point of link 30 and since pin 22 is at the center of curvatureof member 20, it is evident that by reason of the check lever arrangement and action, the center of curvature of member 20 will move along the center line between the pendulums, throughout the range of the scale, which was the desideratum to. be obtained for the reasons given before.

The operation of the load counterbalancing and indicating means is believed clear from the above description of the parts.

It is to be understood that variations, changes,

and modifications may be made which follow the principles of the invention without departing from the spirit or teachings of the invention. It is therefore intended to be limited only by the following claims. 5

What is claimed is as follows:

1. In a scale; a pair of oppositely rockable load counterbalancing pendulums, an equalizer member, an indicator, a driving element for the indicator carried by the equalizer member, and means for converting rocking of the pendulums into movement of the equalizer member in a vertical direction, said means including a tape suspending the equalizer member equally from the opposite pendulums and a check linkage connected 15 to the equalizer member to constrain the latter to movement in said vertical direction along a definite, predetermined path.

2. In a scale; a pair of oppositely rockable load counterbalancing pendulums including round ful- 20 crum elements, an equalizer member having a round peripheral portion and having the center of curvature of said round portion on: a line passing centrally between the fulcrum elements, tape means wound at opposite ends on the fulcrum 25 elements and wound intermediately around said round portion of the equalizer member to suspend the latter from the opposite fulcrum elements and to cause vertical movement of said member upon rocking of the pendulums and their 30 fulcrum elements, load indicating means operated by the member upon vertical movement of the member, and a check linkage connected to the center of curvature of said equalizer member to maintain said center of curvature along said central line between the fulcrum elements during vertical movement of the equalizer member.

3. In a scale; a pair of oppositely rockable load counterbalancing pendulums including round fulcrum elements, spaced tracks along which said fulcrum elements roll during rocking of the pendulums, an equalizer member between the fulcrum elements, tape means suspending the equalizer member from the fulcrum elements to cause movement of the equalizer member in a vertical direction upon rocking of the pendulums, an indicator, a shaft therefor, a pinion on the shaft, a rack for driving the pinion, means for pivotally mounting the rack on the equalizer member, means for maintaining the rack meshed with the pinion, and a check linkage connected to the equalizer member at the pivotal axis of the rack to constrain the rack and member to movement parallel to themselves in said vertical direction.

4. In a scale; a pair of oppositely rockable load counterbalancing pendulums, a load indicator, a rectilinearly movable device for operating the load indicator, connections between the pendulums and device for converting rocking of the pendulums into movement of said device in a rectilinear direction, and a check linkage for constraining the device to movement parallel to itself in said rectilinear direction, said check linkage including a, link connected at its center to aforesaid device and a pair of non-parallel check levers extending in opposite directions from said link and connected to the link at opposite sides of the link center and at equal distances from the link center.

5. In a scale, a pair of oppositely rockable load counterbalancing pendulums, a load indicator, an equalizer member, means carried by the equalizer member for operating the load indicator, tape means suspending the member from 7 the pendulums and causing the member to move in a vertical direction upon rocking of the pendulums, a vertically extending link connected at the center to said equalizer member, and a pair of check levers connected to the link at equal distances above and below the link center, said check lev'ers extending in opposite directions from the link and being arranged at equal angles to the horizontal and at the same side of the horizontal, whereby the link center is constrained to move along the same vertical line throughout rectilinear movement of said equalizer member and whereby said equalizer during its rectilinear movement is held in a definite, predetermined vertical path.

6. In a scale; a pair of oppositely rockable load responsive rolling elements, tracks along which said elements roll, a rounded equalizer member having its center of curvature on a line passing centrally between the rolling elements, tape means suspending the equalizer member from the rolling elements to cause vertical movement of the member upon rocking of the elements, a load indicator, means carried by the said member for operating the indicator upon vertical movement of the member, a link connected at its center to the center of curvature of said member, and a pair of non-parallel check levers extending in opposite directions from the link and connected thereto at equal distances from the link center, the check levers being at similar sides of the horizontal and at equal distances from the horizontal, whereby the link center and the center of curvature of the equalizer member are maintained on said center line between the rolling elements throughout the range of movement of the rolling elements.

'7. In a scale; a pair of oppositely rockable load responsive spools, an equalizer member symmetrically arranged with respect to a vertical line passing centrally between the spools, tape means suspending the member from said spools and causing vertical movement of the equalizer member upon rocking of said spools, a load indicator, means carried by said member for operating the indicator upon vertical movement of the member, a vertically disposed link connected at its center to said equalizer member, and a pair of check levers connected to the link above and below the link center and at equal distances from the link center, the check levers extending in opposite directions from the link and arranged at equal angular distances from the horizontal and at the same side of the horizontal, whereby said link center will be maintained throughout movement of the equalizer member along the same vertical line and whereby the equalizer will be constrained to move parallel to itself during its vertical movement.

EDWARD J. VON PEIN. WILLIAM N. GILBERT.

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