US2538256A

US2538256A - Computing scale

Info

Publication number: US2538256A
Application number: US72970A
Authority: US
Inventors: Malcher Otto
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-01-25
Filing date: 1949-01-25
Publication date: 1951-01-16
Anticipated expiration: 1968-01-16

Description

Jan. 16, 1951 I o. MALcHER 2,538,256

COMPUTING SCALE Filed Jan. 25, 1949 3 Sheets-Sheet 1 Jan. 16, 1951V o. MALCHER 2,538,256

COMPUTING SCALE Filed Jan. 25, 1949 5 Sheets-Sheet 2 O. MALCHER COMPUTING SCALE Jan. 16, 1951 5 Sheets-Sheet 3 Filed Jan. 25, 1949 27206212 07' y OicZ/'Czer Patented Jan. 16, Y19151 UNITED STATES PATENT OFFICE 2,538,256 COMPUTING SCALE Otto Malcher, Chicago, Ill. Application January 25, 1949, serial No. 72,970

14 Claims. l

This invention relates in general to a computing mechanism for indicating and registering values, particularly as used in a computing scale mechanism and is more particularly described as an improvement and simplification of certain of the indicating and registering mechanism as disclosed in my computing scale Patent No. 2,397,970, of April 6, 1946, and is a continuation in part of my application Serial No. 596,299, filed May 28, 1945, now abandoned.

In the prior patent, the indicating and recording values are obtained from a ratchet disc of large diameter having one hundred teeth corresponding to tens graduations and therefore having a considerable momentum requiring'an accurate and eiiicient clutch mechanism to insure that there is no slippage or lost motion which seriously interferes with any computation of values in a machine of this kind.

An important object of the lpresent invention is in the provision of an improved and simplied mechanism reduced in size, and particularly in the diameter of the operating parts to reduce their momentum; to provide a mechanism which may be bodily inserted and substituted for a corresponding part of the mechanism as disclosed in my Patent No. 2,397,970 for effectlng a similar and improved operation thereof.

A still further object of the invention is in the :provision of a computing device having separate parts for hundreds, tens, and units graduations, with means depending upon the movement of the hundreds part for positioning the part having the tens graduation, and means controlled by the position of the part having the tens graduations for positioning the units graduations.

A further object of the present invention is in the provision of a computing device having separate parts for units, tens, and hundreds graduations with means for positioning the part containing the hundreds graduation, in subsequently operating the parts having the tens and unitsgraduations and in aligning the parts and their indicating numerals into full hundreds,

tens, and units graduations.

A still further object of the invention is in the provision of a computing device for registering values having separate parts for hundreds, tens, and units graduations, locking the tens'and hundreds parts together by moving the tens part, and setting up the unit part in accordance with the movement of the tens part. r

Other and further objects ,of the invention will appear in the Spcciidtlfll and .Will be apparent from the accompanying drawings, in which Fig. 1. is a side elevation of a mechanism in accordance with this invention;

Fig. 2 is an edge elevation of parts of the mechanism shown in Fig. 1;

Fig. 3 'and Fig. 4 are fragmentary side elevations of some of the parts shown in Fig. 1, and y associated operating parts; and,

Fig. 5 is an enlarged detail of the mechanism.

A lpart of the mechanism shown in the drawings is designed and intended to be bodily inserted and substituted for a portion of the indicating and registering mechanism which is found in my patent above referred to, the calculated product of two values being set up as described in that patent and the parts having the hundreds and tens graduations, and the notched wheel controlling the units graduations Yclutch all being fastened together and being flexibly connected to and moving with an arm 315 as shown herein and in the said patent.

Referring more particularly to the mechanism shown in the drawings, a shaft 332 corresponds to the money value shaft of the same number as set forth in my prior application in whichA the numerical Iproduct of two variables sets up a projecting arm 315, which is secured to the shaft, in differentvangular or rotated positions depending upon the set value or product. Rotation of the shaft 332 causes rotation of the arm 315 which is held by a spring 314 in engagement with a stop 311 attached to a hundreds wheel or disc 40| free to rotate on the shaft 332 thereby driving the wheel or disc to any position as determined by the Value set up rotation of the shaft.

`The periphery of the disc 40| is spiral in form having nine shoulder reductions 402 and one large shoulder 403 to provide for contact engagement of a visible hundreds indicating numeral device 404.

The hundreds disc stop 311 is located at one side ofthe value set up arm 315 to which it is connected for limited separation movement by the spring 314 and iirmly attached to the hub of the hundreds wheel and movable therewith are two

ratchet discs

405 and 205 with the teeth thereof extending respectively in opposite directions.

shaft 332 and has ten stepped teeth 408 in its outer edge between radial lines which deiine the sector of space between two adjacent shoulders 402 of the hundreds wheel or disc 40|', Also se- A tens segment 401 is freely pivoted on `the 3 cured to or formed integrally with and extcnding oppositely from the segment di?? is an arm 4H having a curved outer edge in which are teeth 4| 3.

To operate the segment 407, a lever 425 is mounted upon an intermediate xed pivot and has a slot 426 at one end engaging a pin 422i projecting from the arm 6| of segment 40'? near its mounting shaft 332 but opposite the toothed portion 408. The other end of this lever Q has a projection 423 which is pressed against a cam E on a cam shaft Il' by a spring 520, thus tending to rotate the segment in the same direction as the disc by means of the lever '325. This movement positions the teeth its of the tens segment in accordance with the position of the hun*- dreds disc and also positions the curved edge lili of the tens segment for controlling the units indicating device as next described.

The tens segment till has two attached spring pressed dogs Ml and 2|? mounted on the same Divot 408 supported by arm MI of the segment Y 401, one adapted to engage the teeth of disc |05 and the other to engage the opposite teeth of disc 205 respectively. Springs 2lb each connected to one dog and to the arm ci i tend to hold the dogs in engagement with teeth tiki and 25d. Both dogs are held out of their disc engaging positions by the contact of a flange 02| on the extremity vof a bell crank 232 rotatable on the intermediate xed pivot 423 and its other end held `against a cam G on cam shaft Il by a spring G22. When the tens segment is moved by leverrl25 in a countwelve in number and need not extend entirely around the periphery of a Wheel as in my previous case referred to above.

The units setting and indicating mechanism may be Yof `any desired or suitable construction or substantially the same as that shown in Fig. ll. of my application cited above, `a part of which is reproduced in Fig. l of the present application t0 show the general construction and operation of theV parts. In order to loch disc 40| and seg ment 401 together in their value indicatingr positions, a locking clutch for tightly gripping the curved outer edge 4t2 is mounted at the end of a `bar |04 p-ivoted at its upper end on shaft 33.2 and extended beyond or below the curved edge v 4|2 of the arm lll and carrying at its lower end jaws |05, |06 at opposite sides of the curved edge which are operated toward and from engaging position by meshing gears lill, one of which is actuated by an attached projecting lever arm l @t normally drawn into clutching position by a spring |09 attached at one end to the arm le@ andthe other end attached to a fixed projection onthe frame (not shown).

This lever is controlled by an actuating lever l in the form of a bell crank mounted at an angle upon a shaft l2 in the machine frame and hav-- ing one arm `extending over the lever arm led, and its other arm having a projection M3 engaging a clutch controlling cam M on shaft Il'.

The timing of this cam is such that as soon as the machine is started for la new value, the probar.

jection H3 of the operating lever is actuated by the cam to move the other arin and press the clutch arm |03 against the tension of spring |09 in a direction to release the clutch jaws from engagement with the curved edge M2. The clutch is not released to allow its application by the spring |09 until the cycle of operation is nearly' complete.

As the segment @0l is conveniently graduated in ten teeth or steps 408; a positive stop is pro vided comprising a movable stop bar i l5 mounted in suitable guides H6. At its end is a tooth lll for engaging any one of the teeth M3. A spring H8 attached at one end to a projection lis on the bar and at the other end to a fixed projection |20 on one of the guides ili urges 'the stop bar into engagement with teeth M3. At the other end of the bar is a pin or projection ll for engaging one of the guides Ne to limit the movement of the stop bar in tooth engaging position.

To control the stop bar H5, allever |22 is mounted intermediate its ends upon a fixed pivot |23 and has `the edge of one extremity 52e in engagement with the projection l@ on the stop At the other end of the lever is a contact member |25 for engaging the 'tens cam K secured Yto the cam shaft il. rThe surface of this cam has a notch which actuates the lever |22 to withdraw the stop bar from its engaging position as soon as the mechanism is started for a calculation and to hold the stop bar out of such engagement until its reengagement.

It may happen that the calculated value is an exact multiple -of ten, that the dog 2li and 4|? will exactly engage their corresponding teeth of

discs

205 and 405 without reverse movement of segment 401, but if there are any variations of the units values, the operating movement of the segment 40'! until the dogs 2|',d and til are engaged and locked together with the teeth of discs 205 and 465, and the backward or truing back movement of segment dell until the stop tooth l l l' engages the next lower tooth H3 causes a pron portional reverse movement which sets up the proper unit on the units value wheels.

This units value movement is effected by an arm |26 pivoted at its upper end on shaft 3R92 and having a rack i 25J at its lower end in engagement with a pinion |26 secured to a relatively xed shaft |33 suitably mounted in the machine frame. A spring |3i is connected at one end to the arm |26 and at the other end to a fixed bar of the machine frame, which tends to move the arm about the shaft 332 in a direction opposed to the value setting up directional movement of the tens segment ffl-0'! by its arm M5, which happens to be a clockwise direction as viewed in Fig. 1.

Attached near the lovver end of arm |26 upon a pivot |32 is a lever |33 having a notch |34 engaged by a projection |35 at the bottom of the clutch supporting bar and the lever having a toothed extremity |35 for engaging the projection |35 if it becomes released from the notch |34. At the other end of the lever |33 is a knock-cut projection |327 which is engaged as hereinafter set forth for disconnecting the arm |26 from the clutch bar lili with which it moves as a unit under ordinary conditions. A spring |43 attached at one end to the holding lever |33 and at the other end to the units movement arm tends to hold the lever with its notch its in engagement With the clutch bar projection |35.

Attached by a rivet itl and projecting from the lower end of the arm |25 is ancperating bar tens segment 437.

having a projection at its outer or free end adapted to engage the surface of a controlling cam I secured to the cam shaft |1 for operating the arm |26 and pressedy against the cam by the spring |3I.

Secured to a sleeve |51' rotatable on shaft |3| is a units value stepped wheel IM), the shaft being rotated by the rack |28 at the lower end of arm |2 and a pinion |28 secured to the shaft, in accordance with the backward movement of the arm as determined by the engagement of the stop tooth with the teeth I3 on the arm Iii i of the On this units stepped wheel Idil are high points |f|| and |56 at the extremities thereof for indicating zero values, and graduated steps therebetween for indicating units values from one to nine. A secondzero projection 53|@ is required on the segment lo? in registering any value over 9% units. The second zero is already in position and shifting of the reading line brings the next full tens line into View instead of 9 and some fraction thereof.

For the present, the sleeve hi'i may be regarded as rotatable with the shaft ISB, but there is a exible connection between them consisting of an arm |68 extending from the units 4wheel lii having a pivot |53 at its outer end toV which one end of a link Ilo is connected, this linl; having a broad but somewhat pointed notch |'ii in its edge for engaging the pointed extremity of an arm |l'2 rigidly secured to the shaft Ito. A spring H3 connected at one end to the outer end of the link il@ and at the other end to a xed point Via on the units wheel Ml! tends to hold the pro-V jection |72 centered in the notch ill,

When the lower end of arm 525 is moved until the stop tooth engages the next tooth H3 in its truing back direction, the shaf i3d is moved and the units wheel S45i is accordingly set withy this truing back movement. For example, if the stop tooth Hl exactly engages one of the teeth M3 after the segment xiii? has been advanced by its operating arm fitti, an even multiple of ten has been set up and no truing back movement of the segment will be required, but ii some intermediate units value such as 827 has been set up, the segment 49? will be moved past the tens tooth indicating 820 and seventenths of the amount for the next tooth. backward movement sets up the units Value wheel ifi@ tor its seventh graduation which operates the units value wheels as hereinafter described.

After` the units Value is set up by the operation of the arm |26 and the units wheel hill, the arm |26 is retained in its set up position and a short time after the next calculation, it is returned by the engagement of its arm lite with the corresponding cam I on the cam shaft il and this movement also returns the units wheel Hit to its Zero position as indicated in Fig. l.

A units operating bar ide has guide slots |43 engaged by fixed proiections lli/2 and has a projecting extremity ifiiat its lower end for engaging the zero high points le! ,and |56 and the intermediate unit value stops of the units wheel |459. Near the upper end of this bar EM is a rack Mii engaging a pinion |511 secured to a units value wheel It@ freely mounted upon a shaft |148, the

wheel having an outer marginal surface, upon which the units values appear in large numerals.

A tens value wheel |53 has an outer marginal surface upon which numerical units appear in large size corresponding with those of a units wheel me. This tens value wheel may be mountn ed freely upon the same shaft |48 `asthat upon which the units wheel |559 is rotatably mounted, and at the hub it is provided with a gear |54 engaging a rack |55 at the upper end of an operating bar' l 5| having a projectingV arm |56 and moved in timed relation to engage one of the teeth il of the segment dill, thereby setting up the tens value in accordance with the segment tooth engaged.

Similarly a hundreds value wheel |51 is mounted upon the shaft |58 and has an outer marginal surface upon which the units numerals appear in large size corresponding to the other two numeral wheels.. At the hub of this wheel |51 is a gear iet engaged by a rack 'It at the upper end or" an operating bar itl having an extending arm itt and operated in timed relation to the units and tens wheels to set up a value on Wheel 557 depending for movement upon the engagement of lan arm projecting therefrom (like the tens arm 53) with one or" the shoulders of the hundreds disc EH depending upon the position of the disc.

A suitable mechanism. for moving the units, tens, and hundreds wheels and their corresponding operating bars Itri, |51, and |Ei| comprises coil springs |8| each connected at one end to a projection of one of the operating bars and at the other end to a fixed bar |62 of the machine.

. These springs tend to move the bars downwardly and itil to indicate the calculated value at the reading line. To set the number wheels at Zero, a cross bar |53 is mounted at the extremities of arms of bell cranks mounted on shaft Q23, and each bell crank having another arm |35 with a projection |86 near the end for engaging similar cams L mounted on rotatable with the tirning shaft i1.

The bar |83 is raised and lowered by the operation of the cams L to engage lower contact ends of the hars left, Ici and |65 against the pressure o springs ISI, and the each have a low place to permit the bar |33 to drop below the wheel operating bars hifi, |5| and iti to set up any calculated valuesr is soon as the machine is actuated for the next calculation, the cams L raise the bar |33 and with it the wheel operating bars setting all the number Wheels at Zero indi-- cation. A

The arrangement of the parts is such that when the value set up arm 375 is moved to any calculated Value by its shaft 3&3?, it carries with it the stop 3'?? on the hundreds disc 49| flexibly connected by sprin- SWL. Thereafter the tens segment till is driven in the same direction by its o erating lever .25 controlled by its timing cam H and spring 2@ to engage the ratchet discs 2th and and'is locked in engagement therewith so that the hundreds disc and the tens segment are, thereafter operated together in both directions of rotation. The unit value which has been set up in thek hundreds disc by the position of the value set up arm and by the position of the tens segment is ampliiied in the position of the head M2.

If the set up value is an even ten, one of the teeth M3 of the head H2 will exactly engage the tooth li' so that there will be no backward or dog reverse movementI of the head 4|2. If it is necessary to move this head rearwardly any portion of the length of one of the teeth before the stop tooth is engaged, this proportion of movement of the head 4|2 sets up the corresponding units value. The clutch mechanism as shown in Fig. 5 is operated in timed relation to engage the head 4|2 and to move with it the proportion of movement of one of the teeth 4|3 to register the units values which in turn allows spring |3| of arm |28 to be moved thereby and correspondingly moving the units wheel |40 as above explained.

The operating bars |44, |5| and I6| are then moved to acuate their corresponding units, tens and hundreds wheels setting up the calculated value in a reading line having numerals of large size.

t is necessary to make provision for the condition which arises when more than nine and onehalf units are set up on the units Wheel |43, thereby requiring a change to the next full tens valuation. A knock-out projection |96 is provided which engages knock-out projection lt of In this knock-out position, a second zero projection |56 forming a part of the units wheel |46 will be located below the units operating bar |45 which communicates the units movement to the units indicating wheel |60 which corresponds with the tens and hundreds indicators located at the reading line.

Engagement of the knock-out projection |96 releases tooth from its engagement with the tooth |34 with which it is in Contact, which allows the hundreds wheel lili and the tens segment to be driven together by spring Bld until the stop Sill again engages the arm 31% in its xed position from which it was separated in the reverse rotational movement, whereby the next higher tens graduation will be restored, the units character being determined by the second zero projection |56, then under the extremity |135 of the indicator operating arm |44.

After the calculated value is set up by the numeral or indicating wheel, the set values may vbe indicated simply by the numbers, and therefore visible to a customer, or the number mechanism may be repeated so that both the customer and the operator may see it on different sides of the machine, or the set value may be printed upon a ticket which is furnished to a customer. The actual value setting up mechanism is shown more clearly in Figs. l and 2, or any similar or equivalent means which may be of any well known or suitable type. i

In attempting to grip a comparatively large value set up wheel and to hold it in a rigid fixed position by means of a clutch mechanism, much difficulty is encountered. After the mechanism has been in use for a short time, a slight give or slippage of the clutch mechanism will make all valuations inaccurate so that the operation of the machine is questionable. The present invention simplifies this feature of my invention above referred to and is intended to provide a positively operated and much more reliable clutch since it is applied at a position near the center of movement of the parts and actually operates upon moving parts of so much less weight as comared with the large wheel structures oi my application above referred to that there is a greater factor of safety and less likelihood of error.

In a machine of this kind, the calculation must be made and completed in 2.1/2 to 3 seconds in order to be considered commercially successful.

The above construction does away with about nine-tenths of the weight of the tens and hundreds wheels as compared with my application above referred to which materially reduces the inertia produced by such masses.

In this form of the invention, greater accuracy of calculation is possible with operating wheels, discs, and parts of smaller sizes. The calculated or set up value is given to a hundreds wheel or a disc 'having tens graduations for its entire circumference, and a tens segment having only tens graduations is positioned thereby and locked thereto. The units value as set up in the hundreds Wheel or disc and by it applied and magnied in the tens segment is spread over a comparatively large surface which makes it possible to position more accurately the set up units value, all valuations depending upon the position of the hundreds wheel.

I claim:

l. In a computing device for indicating numerical values, separate parts for hundreds, tens, and units graduations; means for settinsr up a numerical value dependent upon the position of the hundreds part, means controlled by the value set up in the hundreds part for positioning the tens part, and means controlled by the tens part for positioning the units part, the units part comprising a segment having a single set of ten digit graduations.

2. A computing device, comprising separate movable parts for indicating hundreds, tens and units; means dependent upon the movement of the hundreds part between its positions indicating full hundreds graduations for controlling the movement of the tens part in accordance with the partial movements of the hundreds part, and means dependent upon the movement of the tens part between its full tens graduations for controlling the movement of the units part, the units part having a single set of ten digit graduations for all of the tens graduations.

3. In a computing device for numbers representing values, comprising separate parts having hundreds, tens, and units graduations, operating means for moving the part having hundreds graduations into different relative positions for different values; and means ior subsed erating the part having the tens grad accordance with the position of the hundreds part and the part having the units graduations in accordance with the position of the tens part, the units part having ten graduated steps and movable relatively to each of the tens graduations.

4. In a computing device for numbers indicating values and comprising separate parts having hundreds, tens, and units graduations; means for driving the part having the hundreds graduation to different positions indicating values which comprise units, tens, and hundreds; means for moving the tens part to a position determined by a position of the hundreds part, and meazfis for moving the units part to a position determined by the relative position of the tens part, the units part comprising a segment having only ten units steps and movable relatively to any one of the tens graduations.

5. In a computing device for indicating numerical values, comprising separate parts having hundreds, tens, and units graduations, means for driving the hundreds part to a stop position in one direction including units, tens and hundreds values, means for moving the tens part in the same direction as the hundreds part, until it is stopped thereby, means for locking the tens and hundreds parts for movement together, means for reversing the movement of the tens and hundreds parts to the last full tens graduation, and means dependent upon the amount of said reversing movement for ,positioning the units part, the units part comprising a segment with only one series of ten steps and movable relatively to any one of the tens graduations.

6. A computing device forindicating numerical values, comprising separate parts having hundreds, tens, and units graduations, means for positioning the part having hundreds graduations to indicate a numerical value in accordance therewith, means controlled bythe position of the hundreds part for positioning the tens part, and means `controlled by the tens part 'for separately positioning the units part in accordance `with the positions of the tens and hundreds parts, the units part comprising a segment with only one series of ten unit steps.

7. A computing device for indicating numerical values, comprising separate parts having hundreds, tens, and units graduations, means for moving the part having hundreds graduations to dierent positions depending upon diilerent numerical values, means controlled by the movement of the hundreds part forl engaging the tens part and locking it for movement in either direction therewith, and means controlled by the proportional movement of the tens part between its full tens graduations for relatively moving the units part, the units partV having one series or ten unit steps.

8. In a computing device for indicating numerical Values, separate parts having hundreds, tens, and units graduations; means for driving the hundreds part in one direction to relative positions indicating different values, a iiexible connection between the driving means and the hundreds part to permit a limited movement in `the Yreverse direction, means for positioning the tens part in accordance with the extent of movement of the hundreds part, means depending upon the relative movement of the tens part between full tens values for positioning the units part, the units part having only one series of ten` units steps, and numerical indicating Wheels depending upon the positions of the units, tens, and hundreds part for indicating a numerical value which is originally set up, by the position of the hundreds part.

9. In a computing device for indicating numerical values, comprising separate parts having hundreds, tens, `and units graduations; `means for driving the hundreds part to a value indicating stop position in one direction, a flexible connection between the means and said part, means dependent upon the extent of movement of the hundreds part for moving the tens part in the same direction, means wfor locking the tens and hundreds parts together, means for reversing the movement of the locked tens and hundreds parts to the last full tens graduation, said reversingv movement setting up a graduation of the units part in accordance with said movement and as determined by the positions of the tens and hundreds parts, the units part comprising one series of ten unit steps.

10. In a computing device, comprising separate parts having hundreds, tens, and unit-s graduations, means for moving the hundreds part to a stop position for indicating a numerical value,

10 in' accordance with the extent of movement of the tens part, the units part having a segment with a series of ten unit steps, the step at one end indicating zero, and the segment having a projection forming an additional Zero position at the other end thereof, and knock-out means in connection with the segment for moving it to indicate zero when the segment is moved to register more than nine and one-half units.

l1. A computing device for indicating numerical values, comprising parts having hundreds, tens, and units graduations, means for moving the part having hundreds graduations to a position for indicating a numerical value, means y controlled by the position of the hundreds part for also positioning the tens part, means controlled by the tens part for positioning the units part in acordance with the numerical value set up in the hundreds part and the tens part, the units part having one series of ten unit steps movable relative to each tens graduation, and numerical indicating wheels and operating means for each Wheel engageable with the hundreds, tens, and units graduations to set up different values in the Wheels.

l2. A computing device for indicating numerical values, comprising separate parts having graduations representing hundreds, tens, and units, means for positioning the part having hundreds graduations to indicate a numerical value in accordance therewith, means controlled by the position of the hundreds part for positioning the tens part, means controlled by the tens part for positioning the units part in accordance with the positions of the tens and hundreds parts, the units part having only one Series of ten unit steps movable relative to any tens graduation, numericalrindicating wheels for hundreds, tens, and units values, rack members movably mounted for actuating each of the Wheels separately, and each of the rack members having a projection for engaging corresponding graduations of the hundreds, tens, and units part-s for positioning the Wheels to indicate a numerical value depending upon the position of the hundreds part.

13. In a computing device for indicating numerical values, separate movable parts" for hundreds, tens, and units graduations; means for setting up a numerical value in the hundreds part dependent upon the position thereof, means controlled by the value 'set up in the hundreds part for positioning the tens part, means controlled by the tens part for positioning the units part, the units part having one series only of ten unit steps movable relative Vto any tens graduation, a numerical indicating Wheel for hundreds, tens, and units graduations, means including rack bars for moving each of the wheels separately, each rack bar having `a projection for engaging the graduation of its respective part, and means for moving the rack members so that the projection thereof engage the graduations of their means for driving the tens part to engage the hundreds part means ,for mcvins `the units par@ respective parts for moving the wheels in accordance with the numerical value set up by the positions of the hundreds, tens and unit-s parts.

14. In a computing device for indicating numerical values, separate movable parts for hundreds, tens and units graduations; means for driving the hundreds part to indicate a numerical value in accordance with the position thereof, means for securing the tens part tov the hundreds part for movement together in both directions, means for gripping the tens part and moving it rcversely a proportionate part of one grada,

uation-toindicate units. means for magnifying themovement of the units part in accordance Land means forfmovingithe rack bars to free the projections thereof from engagement with the graduations Vof their corresponding movable .parts 12 untl'said parts are positionedY toin'dicate auml#v inerical value.

REFERENCES 'CITED The following references are of record inthe le of this patent:

UNITED STATES PA'IENI'IIS m Number Name `Date 1,338,282 Boyer A Apr. :27, 1920 1,446,963 Crane HFeb. 127, 11923 2,897,970 Malcher Apr; 9,11946