US1315144A - Overthrow-check for calculating-machines - Google Patents

Description

J. F. MAYS. OVERTHROW CHECK FOR CALCULATING MACHINES. APPLICATION FILED JUNE 24. 918.

1,315,144. PatentedSept.2,1919.

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J. F. MAYS.

OVERTHROW CHECK FOR CALCULATING MACHINES.

APPLICATION FILED .IUNE 24.19I8.

Patented Sept. 2, 1919.

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J. F. MAYS.

OVERTHROW CHECK FOR CALCULATING MACHINES. APPLICAHON mzp JUNE 24.1918.

1 ,3 1 5, 1 44. Patented Sept. 2, 1919.

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UNITED STATES PATENT OFFICE.

JAMES F. MAYS, F BIRMINGHAM, ALABAMA, ASSIGNOR T0 MAYS ACCOUNTING MACHINE COMPANY, OF LEXINGTON, NORTH CAROLINA, A. CORPORATION OF NORTH CAROLINA.

Specification of Letters Patent.

Patented Sept. 2, 1919.

Application filed June 24, 1918. Serial No. 241,523.

useful Improvements in Overthrow-Checks for Calculating-Machines, of which the following is a specification.

This invention relates to improvements in calculating or adding machines and the like and it pertains more especially to the dial actuating mechanism thereof. The primary object of the invention is to provide novel and improved means for effectively preventing overthrow or excess motion of the dials when the same are rotated or advanced incidental to the calculating or adding operation, whereby accurate registration of the numerals on the dials with the openings through which they show is attained, cor rect operation of the ratchet mechanisms through which the dials are actuated is insured, and each dial is permitted to advance at each operation only to the point corresponding to the number advanced into the dial, this feature being particularly advantageous where a'printing attachment is employed in association with the dial as it enables all the characters in printing position on the different printing wheels to be alin d properly.

To these ends, the invention comprises an overthrow check including a pawl and a cooperating toothed wheel, the latter being fixed to the respective dial, said pawl and wheel being normally disengaged to permit a carry to be made into such dial from the dial of lower denomination, the pawl, however, being automatically engaged with the toothed wheel in response to the initial part of the dial driving movement of the dial actuating mechanism, whereby overthrow of the dial, when it has been rotated or advanced to the proper point, due to momentum, is prevented, the pawl being auto matically disengaged from the toothed wheel upon return of the dial actuating mechanism to normal position. Cooperative with the overthrow check for the dial is means for automatically arresting the dial driving motion of the dial driving mecha nism, such means being operative coincident with the action of said check in preventing overthrow of the dial, in consequence of which the dial driving motion of the dial actuating mechanism is arrested at the moment the dial is checked, and hence the momentum of the mechanism through which the dial is actuated is prevented from acting upon the dial with a tendency to cause overthrow thereof.

The invention is applicable to calculating and adding machines of dilferent types, and it is especially applicable to those of the class wherein the dials are actuated by the direct down strokes of the keys and the initial parts of such strokes serve to cause the carry mechanisms for the dials to be held from operation, a machine of this class being shown and described in my copending application, Serial No. 148,559, filed February 14, 1917, and the preferred mechanism for controlling the operation of the carry mechanism being shown and described in my copending application, Serial No. 214,717, filed January 31, 1917.

The preferred embodiment of the invention is shown in the accompanying drawings and will be hereinafter described in detail. It is to be understood, however, that the invention is not restricted to the precise construction shown, as equivalent constructions are contemplated and will be included within the scope of the claims.

In the accompanying drawings:

Figure 1 represents a longitudinal vertical section through a calculating machine embodying an overthrow check constructed in accordance with the present invention, one unit only being shown for clearness in illustration.

Fig'. 2 is a side elevation, on an enlarged scale, of the overthrow check and the part of the dial driving'mechanism by which it is controlled.

Fig. 8 represents an end elevation of the overthrow check as viewed from the right in Fig. 2. i

Fig. 1 represents a section on the line 4t-4: of Fig. 2 and looking in the direction of the arrow.

Fig. 5 represents a section taken longitudinally through the overflow check and associated mechanism shown in Fig. 2.

Fig. 6 represents a transverse section through the common rock shaft for the column of keys showing one of the keys cooperative therewith.

Fig. 7 is an elevation of the key shown in Fig. 6 as viewed from the right.

Fig. 8 is a detail view showing three of the keys and the overthrow mechanism controlled thereby as viewed from the opposite side from which these parts appear in Fig. 1. Figs. 9 and 10 represent transverse sections through the common rock shaft for the column of keys, the sections being taken at different planes longitudinally of such shaft and showing the differential angular spacing of the overthrow stops thereon fordiffcirent keys.

Fig. 11 represents a section on the line 11-- 11 Fig. 5, looking in the direction of the arrow.

The present invention is shown in the present instance as applied to a calculating machine of the class shown and described in my application, Serial No. 148,559 hereinbefore referred to, one unit only of the machine being shown in the present instance and reference being made to said applicati on for a full and complete disclosure of the machine. As shown, 1 designates the casing of the machine which contains the various mechanisms, 2 designates the keys of the column for the respective unit, these keys being reciprocable vertically through the top of the casing, these keys having buttons on their upper ends bearing numbers reading from 1 to 9 inclusive, the button bearing the number 1 being located at the left-hand end, Fig. 1, and the button bearing the numher 9 being located'at the right-hand end of said figure. The keys bearing the numbers 1, 2 and 3 are operatively connected to key levers 3 and the keys bearing the numbrs 4t, 5 and 6 are operatively connected to the key levers 1, the key levers 3 and l being operative upon a suitably stepped crossmember 5 which is carried by a bar 6, the latter being guided to reciprocate vertically within the casing and is provided with means for operatively connecting it to a rock shaft common to all the key bars, as will be hereinafter described. The key levers 3 and 4 are differentially pivoted in the casing in the manner and forthe purposes described in my application Serial No. 148,559. The keys bearing the numbers 7, 8 and 9 are without key levers, these keys having a direct action upon the common rock shaft. The common rock shaft 7 is journaled in suitable supports 8 and 9 within the casing and it has fixed thereto toothed pinions 10 and 11, the keys corresponding to the numerals 7, 8 and 9 having toothed racks 12 thereon which are adapted to mesh with the respective pinions 10, and the bar 6 whichis common to the keys bearing the numbers 1- 6 inclusive carries a toothed rack 13 which is adapted to cotiperate with the pinion 11 on the common shaft. An arm 1% is fixed to the shaft 7 in proximity to each pinion thereon and a pin or projection 15 is located at one side of each rack 12 or 13 and is adapted to bear against the respective arm 14-. In consequence, descent of any one of the keys bearing the numbers 7, 8 and 9 or the bar 6 which is common to the keys hearing the numbers 1 to 6 inclusive will initiate rotation of the shaft 7 through the action of the respective pin 15 on the corresponding arm 14L, and continued descent of such key or bar will further rotate the shaft 7 through the action of the rack 12 or 13, as the case may be, upon the respective pinion 10 or 11. The shaft 7 is rotated differentially in conformity with the particular key which is actuated as explained in my copending application, Serial No. 118,559, it being understood that one of these shafts 7 is provided for each column of keys comprising a unit of the machine and that any desired number of units may be used. The shaft is restored to normal position after each actuation thereof by a spring 16 and each key is restored to its normal elevated position by a spring 17 The dial 18 for each unit is fixed to a dial shaft 19, the latter being mounted in suitable bearings 20 and 21 arranged within the casing and, in the present instance, the top of the casing is provided with a sight opening 22 through which each numeral on the dial is visible as such numeral is advamed into operative position. The carry mechanism for carrying a numeral into this dial from the dial of the next lower denomination is shown generally and it corresponds to that shown and described in my copending application, Serial No. I l-8,559, to which reference is made for a full. description thereof, this carry mechanism being controlled by a cam 24 fixed on the shaft 7 and cooperative with a roller 25, the latter being carried by a lever 26 which is pivoted at 27 to a station ary bracket 28, and the free end of the lever 26 is connected to the carry control. mechanism by a link 29.

The dial fixed on the dial shaft 19 is driven through a ratchet mechanism 36. This ratchet mechanism comprises an internally toothed driven member 31 which is fixed to the dial shaft 19, a driving member 32, and a pawl 33, which pawl is carried by the driving member 32 and is arranged to cooperate with the ratchet teeth of the driven member 31, the pawl being operative upon such teeth during advancing movement of the driving member 32 and the pawl riding idly over the teeth of the driven member 31 during return movement of the driving member 32. The driving member 32, as shown, is fixed to a sleeve 34 which is revoluble On the dial shaft 19, and a second sleeve v 35 is fitted revolubly over the sleeve 34, the

outer sleeve 35 having a pinion 36 fixed thereon. The pinion 36 meshes with and is actuated by atoothed sector 36 which is fixed on the shaft 7 of the respective unit, motion imparted to this shaft 7 through actuation of the keys being transmitted to the respective dial through the medium of the pinion 36 and the ratchet and pawl mechanism 31, 32 and 33.

The overthrow check for preventing excess motion of the dial is also applied in the present instance to a machine of the class disclosed in my copending application, Serial No. 148,559, wherein the initial part of the down stroke of any key is utilized to lock the carry mechanism from operation and it is further applied to a mechanism such as that shown and described in my' copending application, Serial No. 214,717, whereby lost or idle motion is afforded the dial driving pinion 36 in response to the initial part of the down stroke of a key and the carry mechanisms may be locked before advance of any dial commences. Preferably, and as shown in the present embodiment of the invention, this preliminary lost or idle motion of the pinion which permits actuation of the carry control mechanism is utilized to actuate the overthrow check for the dial. In the construction shown, the overthrow check for the dial comprises a toothed wheel 37 which is fixed to the dial shaft 19, this wheel being provided with ten peripheral equidistantly spaced teeth 38 which correspond in number and location to the numerals on the dial, a disk or other suitable member 39 which is fixed to the sleeve 34 to which the driving member 32 of the ratchet mechanism is fixed, a pawl 40 which is pivoted at 41 to the disk 39 and has a tooth or projection 42 arranged to engage the advance side of any one of the teeth 38 on the wheel 37 a pin 43 being fixed to the pawl and extending through a slot 44 in the disk 39, and a d1sk or other appropriate member 45, the latter being fixed to the outer sleeve 35 to which the pinion 36 is fixed, this disk 45 being formed with a cam slot 46 into which the pin 43 projects. A suitable spring 47 acts on the pawl 40 with a tendency to disengage it from the toothed wheel 37 and to normally hold the pawl in such position, the move ment of the pawl 40 under the influence of the spring 47 being limited by engagement of the pin 43 with the outer end of the slot 44. The cam slot 46 in thedisk 45 has a cam surface 48 formed on its outer edge, the pin 43 being arranged to cooperate with this cam surface. The pinion 36 is capable of limited angular movement relatively to the ratchet driving member 43, the pinion being connected to the member 32 through the medium of a spring .49 one end of which is attached to a pin 50 which is fixed to the pinion and the other end of which is attached to a pin 51, the latter pin extending through a circumferential slot 52 formed in the pinion and being fixed to the member 32. As shown and described in my copending application, Serial No. 214,717, the spring 49, when the pinion is in normal position, acts to rotate the pinion in the direction indicated by the arrow in Fig. 11 and to also rotate the member 32 in a reverse direction. Such reverse rotation of the member 32 is limited by the engagement of the stop 53 on the member 32 which rest-s against a fixed stop 54. The pinion is ro tated in the direction of the arrow (Fig. 11) in response to the down stroke of any one of the keys of the column belonging thereto. The initial part of such rotation of the pinion causes the pin 51 to recede toward the opposite end of the slot 52 in consequence of which the member 32 will be idle or will remain stationary during this advance rotation of the pinion. As a result, the disk 39 which is fixed to the member 32 will remain stationary during this advance rotation of the pinion while the disk 45 will rotate during this advance movement of the pinion, in consequence of which the cam surface 48 formed on the outer edge of the slot 46 in the disk 45 will act upon the pin 43 attached to the pawl 40 and will cause the pawl 40 to move inwardly, bringing its tooth or projection 42 into engagement with the advance side of the adjacent tooth 38 on the wheel 37 When the preliminary or advance movement of the pinion has been completed, the continued descent of the key causes the member 32 to advance in unison with the pinion 36 as a result of the engagement of the right hand end of the slot 52 with the pin 51, the pinion and the driving member 32 of the ratchet mechanism then advancing in unison, the dial being ad vanced through the medium of the ratchet mechanism, and, also, the disks 39 and 45 will advance in unison with the pinion 3G and the member 32. The toothed wheel 37 which advances in unison with the dial and is fixed to the dial shaft is held by the pawl 40, in consequence of which rotation of the dial through an angle or arc greater than that through which the pinion 36 and ratchet driving member 32 advance is prevented.

Overthrow or excess motion of the keyoperated dial actuating mechanism which acts upon the pinion 36 is also prevented. In the construction shown for accomplishing this purpose, the shaft 7 which is common to all the keys of the respective column is provided with graduated 01' differentially spaced stop arms which are arranged to coiiperate with stops, such stops being controlled by the respective keys of the column whereby the shaft 7 is permitted to rotate only through an angle corresponding to the extent of advance which is to be imparted to the dial by the respective key. In the present instance, a series of radial arms 55 is fixed to the shaft 7, these arms being located beside the respective key bars, and these arms are set at different angles with respect to the axis of the shaft 7 according to the extent of rotation which is to be imparted to such shaft by the different ke s. The guide 56 through which the lower ends of the key bars operate is preferably angleshaped in cross-section, the upstanding flange 57 thereof having extensions 58 projecting from its upper edge, the upper edge of each projection being curved, as shown at 59, and these upstanding projections 58 are located immediately beside the paths of the respective stop arms 55. A set of stops shown in the form of levers 60 are pivoted at 61 to the upstanding fig nge 57, the upper end of each stop being bent laterally to form a foot 62 which overlies the upper end of the respective projection 58, the lower end 63 of each stop being bent laterally, as shown, and arranged to cotiperate with a bevel or other ca-m surface 6% at or adjacent to the lower end of the respective key bar. A spring 65 operates with a tendency to pull the foot 62 of each stop out of the path of the respective stop arm 55, a pin 66 limiting the movement of the stop in such direction. Normally, with all of the keys in elevated position, the stops 60 are in the position shown in Fig. 8, the feet 62 thereon being then clear of the paths of the respe'0 tive stop arms 55. However, depressionpf any key causes the cam or bevel 64, during the initial part of such movement, to deflect the end 63 of the respective stop 60, thus bringing the foot 62 on the upper end of the stop into the path of the respective stop arm 55, the foot 62 remaining in such position during the continued descent of the key, and hence the stop arm 55 corresponding to the depressed key will come into engagement with the foot 62 when the key has been depressed to the proper limit of its stroke. Owing to the differential connections of the different keys to the shaft 7, th latter will be rotated through 'difierent angles upon depression of the different keys, and it will. be understood that the stop arms 55 are set at different angles or spaced circumferentially of the shaft 7 to conform with the different ranges of advance imparted to the shaft 7 by the different keys. Owing to the rack and pinion connections between the key bars and the shaft 7, the key bars as well as the shaft 7 will be arrested in their movements when such parts have been actuated to the proper extent, and hence over-motion of either the shaft 7 or the key bars cannot occur, in consequence of which over-motion cannot be transmitted from the shaft 7 through the sector 36 to the pinion 36.

In the direct key-operated type of machine to which the invention is shown applied in the present instance, all the stops for the common actuating shaft will be normally in inoperative position while the keys are in their normal raised position and, also, the pawl and toothed wheel of the overn1otion check for the dial will be disengaged. The initial part of the down stroke of any key of the respective column will, however, set the stop individual to such key in position to arrest rotation of the shaft at the proper point corresponding to the extent of rotation which is to be imparted to the shaft by such key, and, coincident-1y, such initial part of the down stroke of the key will engage the pawl with the toothed wheel of the over motion check for the dial. This initial part of the down stroke of the key also effects locking of the carrying mechanisms for the dials, as will 'be understood from the hereinbeforementioned applications, the dial remaining motionless during such period owing to the lost motion connection between the pinion and the dial actuating ratchet mechanism. Continued motion in the depression of the key effects advance of the respective dial to an extent corresponding to the numeral represented by the particular key which has been depressed, the appropriate stop arresting motion of the shaft and the key connected thereto when such key has been depressed to the proper extent and the pawl and toothed wheel concurrently arresting rotation of the dial when the latter has been advanced to the proper extent in accordance with the key which 5 has been depressed. Release of the depressed key permits the same and the actuating shaft connected thereto to return to normal position and, simultaneously, the pinion and dial actuating ratchet mechanism return to 1 normal position, the movement of the pinion toward normal position beginning immediately at the commencement of the return movement of the key and preceding the commencement of the return movement of 11 the ratchet mechanism, and during this relative movement between the pinion and ratchet mechanism, the pawl of the overmotion check is caused to disengage from its coiiperating toothed wheel, and during 0 the final part of the return movement of the key, the stop corresponding to the depressed key returns to its normal inactive position and the carry control mechanism is released or unlocked, thus permitting a carry to be made into the dial if such carry is due.

The means provided by the present invention for preventing over-throw or excess advance of the dial is relatively simple and compact in its construction, it may be easily applied to the machine, this being especially so when it is applied to machines of the' class shown in the present instance where it utilizes the lost motion connection between the dial and its actuating pinion for setting the dial check into and out of operative position, it is certain in its operation, and it does not impair the speed and facility of operation of the machine.

The means provided by the present invention for preventing overthrow is particularly adapted for use in a calculating machine wherein the dials are actuated or advanced directly by the downstrokes of the keys. In such machines, the dials have a marked tendency to overthrow, this being especially true when the 7 8 and 9 keys are operated, at which times the dials are rotated through relatively large angles and at high velocity. The overthrow checki herein provided, however, fulfil the conditions imposed upon it in a machlne of the type referred to for the reasons that the dial and its actuating means are concurrently checked at different points between the keys and the dials, and that the overthrow checks for the dials and also the actuating mechanisms therefor are set 1n operative position in response to the initial part of the dial actuating stroke of the key and before the dial commences to advance in response to such key stroke, certamty 1n the operations of the overthrow devices being thereby insured, even though the keys may be actuated quickly and in repetition.

I claim as my invention 1. In a calculating machine, a dial, actuating mechanism therefor, an overthrow check, and means for settingsaid check 1n position to prevent excess mot1on of the d1al prior to advance of the dial by said actuating mechanism and for holdmg the check in such position during the advance of the dial.

2. In a calculating machine, a numeral wheel, actuating mechanism therefor, an overthrow check for preventing excess motion. of the numeral wheel incident to its advance, and means for setting said overthrow check in active condition by the inltial operation of said actuating mechan sm and for holding the check in such condition during the advance of the numeral wheel.

3. In a machine of the class described having a numeral wheel and actuating mechanism therefor, an overthrow check movable into and out of position to prevent excess motion at the termination of the advance of the numeral wheel, and means for automatically setting said check in operative position by the initial part of the operation of the actuating mechanism and prlor to the advance of the numeral wheel and for-positively holding the check in such position during the advance of the numeral wheel.

4. In a machine of the class described, a

means for setting said check in operative position during said preliminary movement of the dlal advancing means.

6. In a machine of the class described, a

dial, actuating means therefor movable in one direction to advance the dial and capable of a return movement, said actuating means having an idle movement preliminarily to its dial actuating movement and also during its return movement, and an overthrow check set in operation to prevent excess advance of the dial during said preliminary idle movement of the actuating means and set in inoperative position during the return movement of the actuating means.

7 In a machine of the class described, a

' dial, actuating means therefor movable in one dlrection to advance the dial and capable of a return movement, said actuating means havmg idle movements relatively to the dial preliminarily to its dial advancing and return movements respectively, an overthrow check for preventing excess motion in the advance of the dial, and means'for setting said check in operative position during the preliminary idle movement of the actuating means prior to the advance of the dial and for rendering the check inoperative during the idle movement of the actuating means preliminarily to its return.

8. In a calculating machine having a dial, a key, and actuating means responsive to a down stroke of the key to advance the dial, a member for connecting together the dial and its actuating means to prevent excess motion in the advance of the dial, and means for setting said member in operative position prior to the commencement of advance of the dial.

9. In a calculating machine having a dial, a key, and actuating means responsive to a down stroke of such key to cause advance of the dial, a member for locking together the dial and its actuating means to prevent ex-v cess advance motion of the dial, and means for setting said member in operative position prior to the advance of the dial in response to the down stroke of the key and for rendering said member inoperative in response to the return stroke of the key.

10. In a machine of the class described, a

dial, actuating means for advancing it, said actuating means being capable of motion relatively to the dial preliminarily to its dial advancing movement, a toothed wheel fixed to move with the dial, a pawl carried by an operative part of the dial actuating means and arranged to cooperate with such wheel, and means operative during said preliminary advance movement of said actuating means to set said pawl in cooperative relation with said toothed wheel.

11. In a machine of the class described, a rotatable dial, a toothed wheel connected to turn therewith, a dial actuating pinion having a lost motion connection with the dial, a pawl adapted to engage and disengage relatively to said toothed wheel, and means operative in consequence of the lost motion between the pinion and dial for setting said pawl in engagement with said toothed wheel prior to the advance of the dial.

12. In a machine of the class described, a rotatable dial, a toothed wheel fixed to rotate with the dial, a dial actuating pinion capable of limited rotation relatively to said dial and also connected to rotate with the dial to advance it, a pawl adapted to cooperate with said toothed wheel to prevent overthrow of the dial in its advance, and means operative by said relative movement between the pinion and dial for setting said pawl in cooperative relation with said toothed Wheel.

13. In a machine of the class described, a rotatable dial, ratchet dial driving mechanism comprising a driving member rotatable relatively to the dial and a driven member connected to rotate with the dial, actuating means for advancing the dial including a pinion having a lost motion connection with the driving member of the ratchet mechanism, a toothed wheel connected to rotate with the dial, a member connected to turn with said driving member of the ratchet mechanism and carrying a pawl adapted to,

cooperate with said toothed wheel, and means operative in consequence of the lost motion between said pinion and dial for controlling the relation between said pawl and toothed wheel.

14. In a machine of the class described, a rotatable dial, ratchet dial driving mechanism comprising a driving member rotatable relatively to the dial and a driven member connected to rotate with the dial, actuating means for advancing the dial including a pinion having a lost motion connection With the driving member of the ratchet mechanism, a toothed wheel connected to rotate with the dial, a member connected to turn with said driving member of the ratchet mechanism and carrying a pawl adapted to cooperate with said toothed wheel, and a member connected to rotate with the pinion and having a cam cooperative with said pawl to control the engagement of the pawl ,corresponding to the different keys of the with said toothed wheel in consequence of said lost motion between the pinion and dial.

15. In a calculating machine, a dial, a column of keys, means operative in response to a down stroke of one of such keys to advance the dial, means for preventing overthrow of such key and dial operating means incident to the down stroke of the key, and means operative coincidently to set said overthrow means in condition to connect together the dial and its operating means and thus prevent overthrow of the dial.

16. In a calculating machine, a dial, actuating keys, means operative in response to the down stroke of a key to advance the dial, means set by the initial part of the down stroke of the key to prevent overthrow of said dial advancing means, and means also set by the initial part of the down stroke of the key to prevent overthrow of the dial.

17 In a calculating machine, a dial, a column of actuating keys, dial actuating means operative differentially in response to the down strokes of the different keys to advance the dial, means set by the initial part of the down strokes of the respective keys for preventing overthrow in the operation of said dial actuating means, and means cooperative with the dial and also set by the initial part of the down stroke of the respective keys for preventing overthrow in the advance thereof.

18. In a calculating machine, a dial, a column of keys, actuating means operative in response to the down strokes of the keys to advance the dial and including a rock shaft common to the keys of said column, stops adapted to arrest said shaft at different points in its rotation, and means set by the different keys of the column for controlling said stops.

7 19. In a calculating machine, a dial, a column of keys, means operative in response to the down stroke of said keys for advancing the dial, said means including a shaft common to the keys of the column, a set of stops column and adapted to differentially limit the extent of rotation of said shaft, and means controlled by the different keys for setting the respective stops in operative condition.

20. In a calculating machine, a dial, a colv umn of keys, means operative in response to the down strokes of said keys for advancing the dial, said means including a shaft com- 20 mon to the keys of the column, a set of stop arms fixed in different angular positions on said shaft and corresponding to the respective keys, and a set of stops each movable into the path of its corresponding stop arm upon the down stroke of the respective key.

21. In a calculating machine, a dial, a key, dial actuating means operative in response to the down stroke of such key to advance the dial, said means including a shaft, a

stop arm fixed to said shaft, and a stop movable into the path of said stop arm in response to the initial part of the down stroke of such key.

22. In a calculating machine, a dial, a key having a'stem, dial actuating means operative in response to a stroke of such key to advance the dial, said actuating means carrying a stop to limit its dial advancing movement, and an overthrow means normally located in the path of said key stem and set into operative relation with the stop means by said stem in consequence of the initial part of a stroke of such key and held in such relation by the key stem during the subsequent dial actuating move ment of the key.

In testimony whereof I have hereunto set my hand in presence of tWo subscribing Witnesses.

JAMES F. MAYS. Witnesses:

C. A; BATEMAN, CHAS. S. HYER.

Copies of this patent may be obtained for five cents each, by addressing the "Commissioner of Patents, Washington, D. 0."

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