US3448639A - Indicating apparatus - Google Patents

Description

June, 10, 1969 c. E. ADLER 7 3,448,639

I INDICATING APPARATUS I Filed June 22. 1967 Sheet 1' -of 4 INVENTOR. CLARENCE E. ADLER June 10, 1969 c. E. ADLER INDI CATING APPARATUS Sheet 2 of4 Filed June 22. 1967 I NVENTOR.

June 10, 1969 c. E. ADLER 3,448,639

INDICA'I'ING APPARATUS Filed June 22. 1967 Sheet 2 of 4 COINCIDENCE cmcuns Isa INVENTOR. CLARENCE E. ADLER ATTORNEY June 10, 1969 'QEADLER v 3,448,639

INDICAIING APPARATUS Filed June 22. 1967 Sheet 4 of 4 lir. i es m. I" 31 g ?92 23 Ill 9 E I i 22 I h v 63 x: 4 (D 9 69- '90 8 I 43 as l 59 l'a'z I93 INVENTOR. CLARENCE E. ADLER F:'g 6 BY f-Lww Z4 M ATTORNEY 9 United States Patent 3,448,639 INDI'CATING APPARATUS Clarence E. Adler, Toledo, Ohio, assignor, by mesne assignments, to The Reliance Electric and Engineering Company, Toledo, Ohio,, a corporation of Ohio Filed June 22, 1967, Ser. No. 648,130

Int. Cl. F16h 27/04 U.S. Cl. 74-822 11 Claims ABSTRACT OF THE DISCLOSURE A numerical display device comprising a rotatable member to be rotated to a readout position corresponding to information in an electrical circuit, drive means (intermittent gearing) for locking the member in a dwell position and later for rotating the member, and Stopping means operable during the dwell to disengage from and reengage with the member when successive readout positions are alike, and operable when successive readout positions are unlike and after the dwell for stopping the member in the readout position.

The basic readout device is disclosed in U.S. application Ser. No. 416,526, filed Dec. 7, 1964, in the name of Clarence E. Adler and includes a series of modules each comprising a detent wheel which is directly gear-connected to a rotatably mounted commutator and to a print wheel. Each module indicates the digits of a particular denominational order. When the turning print wheel approaches the correct indicating position, a stopping pawl intercepts the correct one of the teeth of the detent wheel to arrest the detent wheel and thus the print wheel. In the prior basic device, in order to prevent the stopping pawls from catching on the tips of the teeth and causing damage, electrical phasing circuitry is employed as disclosed in U.S. Patent No. 3,147,470 issued Sept. 1, 1964, to R. E. Bell and R. C. Loshbough.

In the prior basic device, the stopping pawls move back under the stopping impact and when lifted up off the detent wheels, they move slightly as driven by their drive springs. The detent wheels also move slightly, but in a direction opposite to the direction in which the pawls move, because they are connected to their drive shaft through spring clutches. Hence, the pawls cannot be dropped into the same tooth pockets without catching on the tips of the teeth. To accommodate this, the detent wheels in the prior device are driven ahead after the pawls are lifted up at least two digit positions.

In the improved readout of the invention, in one embodiment, a pair of intermittent gears reverses the detent wheels ten degrees at the start of a readout cycle to compensate for the slight movement of the pawls and of the detent wheels when the pawls are lifted up off the detent wheels, then locks the detent wheels during a dwell period, and then drives the detent wheels ahead when successive readout signals are unlike. The readout signal is applied before the intermittent gear pair drives the de tent wheels ahead. If the readout signal is the same as the preceding one, the pawls drop squarely into their tooth pockets. If the readout signal is different from the preceding one, the readout wheels rotate until coincidence is reached between the information in an electrical circuit and the positions of the readout wheels.

The intermittent gear pair includes a rotatably mounted driver face gear and a rotatably mounted driven face gear each including a plurality of peg teeth and the driver gear further including a locking ring, the locking ring engaging peg teeth on the driven gear to lock the driven gear during part of a rotative cycle of the driver gear and the peg teeth on the driver gear engaging peg teeth on the driven gear to drive the driven gear during another part of the rotative cycle. The locking ring also includes a cam surface for reverse driving the driven gear during still another part of the rotative cycle.

In the improved readout of the invention, in a second embodiment, the locking ring does not include the cam surface for reverse driving. The intermittent gears lock the detent wheels at the beginning of each cycle to provide a dwell during which the pawls are lifted up off the detent wheels and replaced when successive readouts are alike.

The intermittent gear pair with or without the cam surface can be used in devices other than numerical display devices to provide timing and driving functions, e.g., in printers.

This invention relates to intermittent gearing and to readout devices which are phased mechanically in contrast to the electrical phasing disclosed in the above U.S. Patent No. 3,147,470.

The objects of this invention are to improve numerical display devices, to provide means in the nature of a mechanical supervisory control for phasing the events in mechanical drive numerical display devices, to provide mechanical means for timing and driving the working parts in such devices, and to provide improved intermittent gearing.

The above and other objects and features of this invention will be appreciated more fully from the following detailed description when read with reference to the accompanying drawings wherein:

FIG. 1 is a fragmentary isometric view of the numerical display device showing one readout module in place which indicates the digits of a particular denominational order and the intermittent gear pair of the invention which provide timing and driving functions;

FIG. 2 is a side elevational view of a cam and its follower, the follower being shown fragmentarily in FIG. 1 indicating the general position of the cam and its follower in the display device;

FIG. 3 is an enlarged, vertical sectional view taken along the line 33 of FIG. 1;

FIG. 4 is a schematic diagram of the circuit controlling the indication of a count;

FIG. 5 is a horizontal sectional view taken generally along the line 55 of FIG. 6;

FIG. 6 is a fragmentary side elevational view showing the intermittent face gears illustrated in FIG. 1; and

FIG. 7 is a modified intermittent face gear pair in which the locking ring on the driver gear does not have a cam surface for reverse driving.

Referring to the drawings, the numerical display or readout device is constructed on a base 20 supporting two spaced-apart, elongated blocks 21 (only one shown in FIG. 1) and two side plates 22. The side plates 22 are joined together by means including a flat block 23 at the upper front end of the device, screws 24 (one shown in FIG. 5) extending through the plates 22 and threaded into the block 23 holding the plates and the block together, a circumferentially grooved upper rod 25 at the upper rear end of the device, nuts 26 on shouldered, threaded ends of the rod holding the plates and the rod together, and

a circumferentially grooved lower rod 27 at the bottom end of the device, screws 28 (one shown in FIG. 5) extending through the rod and threaded into the blocks 21 securing the rod to such blocks. The complete device comprises a plurality of duplicate sub-assemblies of unit construction, one for each place in the number to be indicated. Each module has all of its working parts mounted on a module plate 29 which is connected in the display device by moving it vertically, downwardly until a notch 30 (FIG. 3) in the plate 29 is received in one of the circum- 3 ferential grooves in the lower rod 27 and until the back end of the plate 29 is received in one of the circumferential grooves in the upper rod 25. A set screw 31 threaded through the block 23 holds the module plate 29 in place.

The numerical display device is driven by a continuously moving belt as shown in the above U.S. application Ser. No. 416,526 that drives a shaft 34 which is journaled in bearings 37, one shown in that one of the side plates 22 illustrated in FIG. 5. The shaft 34 drives a one-revolution clutch 38 which rotates a gear 43 and a cam 45 on the shaft 34 one revolution per readout cycle as shown and described in the above U.S. application Serial No. 416,526, gear 43 and cam 45 corresponding to gear 43 and cam 45 shown in such application.

The gear disclosed in the above U.S. application Serial No. 416,526 which corresponds to the gear 43 meshes with a gear which corresponds to a gear 61 (FIG. 6). In the readout device of the invention, intermittent gearing comprising a rotatably mounted driver face gear 59 and a rotatably mounted driven face gear 60 operatively connects the gears 43 and 61. However, the function of the gear 61 is the same as that of the corresponding gear disclosed in the above U.S. application Serial No. 416,526. The gear 61 is attached by means of screws 62 to a hub 63 which is rotatable in a bearing 64 that is held on the side plate 22 by means of a nut 65, a C-clip 66 retaining the hub 63 in the bearing 64. The hub 63 defines a square hole which receives a square shaft 68 that is fixed in the hub 63 for rotation therewith by means of a set screw 69. The square shaft 68 functions to drive the working parts on the module plates 29. The gear 61 turns 190 degrees for every 360 degree turn of the gear 43.

The modules or duplicate subassemblies each includes a detent wheel or toothed-member 70 which is directly gear connected to a dual commutator 71 (FIG. 1) and to a print wheel 72 (FIG. 1). The detent wheel 70 is formed of one molded piece having a gear portion 73 and twentyfour teeth 74 which cooperate with a stopping latch pawl 75. The detent wheel 70 is driven by the square shaft 68 through a clutch 76. The clutch 76 is a slip clutch having a drum 77 on the square shaft 68. The square shaft 68 is received in a generally square hole '88 in the drum 77 so that the shaft 68 and the drum 77 turn together as one. A generally square opening 82 in the detent wheel 70 is provided with partially curved sides 83 forming two sharp edges 84 in each side of the generally square opening 82. The clutch 76 also includes four fiexure spring plates 85 one along each of the four sides of the generally square opening 82. In operation, when the stopping latch pawl 75 is withdrawn from the teeth 74, the square shaft 68 drives the detent wheel 70 through the clutch 76, there being enough friction between the fiexure plates 85 and the drum 77 to make the drum 77 and the detent wheel 70 turn together as one. However, when the stopping latch pawl 75 engages a tooth 74 of the detent wheel 70, the flexure plates 85 slip on the drum and the detent wheel 70 is stationary while the drum turns. The print wheel 72 is a rotatable element to be positioned according to information in an electrical circuit, and the detent wheel 70 is a slip-clutch driven toothed-member directly gear connected to the rotatable element 72 and to the commutator 71 for driving them. The latch pawl 75 is part of stopping means and is engageable with the teeth on the toothed-member for stopping the print wheel 72 in the position corresponding to the information.

The module is removed from the readout device as a unit assembly by loosening the set screw 69 (FIG. withdrawing the square shaft 68 from the generally square opening 88 (FIG. 3) in the drum 77, loosening the set screw 31 (FIGS. 1 and 3) and lifting the module plate 29 out of the readout device.

The gear portion 73 of the detent wheel 70 meshes with a gear 86 (FIG. 1) on the side of the print wheel 72, bearing printing type 89, mounted for rotation on a stationary shaft 90 extending between the blocks 21. The print wheel 72 turns twice for each turn of the detent wheel 70 (2:1 ratio) and has twelve printing positions.

The gear portion 73 of the detent wheel 70 also meshes with a gear 91 on the dual commutator 71, the commutator consisting of a single flat metal plate having the double function of being formed with gear teeth on its periphery and having the commutator electrical pattern shown in the above U.S. application Serial No. 416,526, the pattern being separated from the metal plate by a layer or coating of epoxy resin. The commutator 71 (FIG. 1) is shown removed from the module in FIG. 3 to reveal the structure behind it. The commutator electrical pattern as viewed in FIG. 1 is on the back of the commutator 71 concealed from view. The commutator flat plate is rotatable on an internally threaded stationary stud 94 (FIG. 3) in the module plate 29, there being a screw 95 (FIG. 1) received in the internally threaded stud holding the commutator in place. The commutator 71 is located in a housing 96 secured to the module plate 29 which functions to support a double set of brushes 97 which are molded for support in the housing 96. Leads 98 for the brushes are shown in FIGS. 1 and 3. When the commutator is in place, the brushes 97 contact the electrical pattern.

The modules or duplicate subassemblies also each includes the stopping latch pawl 75 which is pivoted to the module plate 29 at 99 and is urged about the axis of such pivot by a coil spring 100, extending between a projection 101 on the plate 29 and a projection 102 on the pawl 75, clockwise toward the detent wheel teeth 74. A reset finger 103 is pivoted at 104 to the module plate 29 and is urged about the axis of such pivot by a coil spring 105, extending between a projection 106 on the plate 29 and a projection 107 on the finger 103, counterclockwise toward the latch pawl 75. A reset lever 108, which is carried on a square portion 109 of a shaft 110 (FIG. 5) having round ends journaled in bearings 111 (one shown in FIG. 5) in the side plates 22, moves from its solid line position shown in FIG. 3 down to its broken line position shown in FIG. 3 and then immediately back up to such solid line position at the beginning of each cycle to reset the latch pawls 75 on all of the duplicate subassemblies. When the reset level 108 is in its down position, the spring 105 pivots the reset finger 103 counterclockwise into engagement with the latch pawl 75, overcomes the force of the spring 100, and pivots the latch pawl 75 counterclockwise in opposition to its spring into engagement with the core 112 of a solenoid 113 carried by the module plate 29. The solenoid 113 when energized holds the latch pawl 75 up out of engagement with the detent wheel teeth 74 when the reset lever 108 moves back to its solid line position shown in FIG. 3 moving the reset finger 103 clockwise in opposition to its spring out of engagement with the latch pawl 75. When the detent wheel 70 approaches the position at which it is to stop, the solenoid 113 is deenergized and the spring 100 pivots the latch pawl 75 clockwise about its pivot 99 into stopping engagement with one of the twenty-four teeth 74.

The reset lever 108 is driven by the cam 45 which as indicated by the curved arrow in FIG. 2 is rotated clockwise one revolution per readout cycle. 'The cam 45 is round except for a depression 117. The shaft carries a bifurcated member 118 which carries in turn a camfollowing roller 119 between its bifurcations. The roller 119 follows the cam 45. The cam 45 is shown in its home position in FIG. 2. An instant after the cam 45 starts rotating, the roller 119 moves down into the cam depression 117 causing the reset lever 108 to [move from its solid line position to its broken line position shown in FIG. 3 and then soon moves back into its original position as the cam depression 117 passes by to return the reset lever 108 to its solid line position, i.e., the reset lever 108 as viewed in FIG. 3 quickly moves down and then back up at the beginning of every readout cycle, and the stopping latch pawls 75 are moved away from the detent wheel teeth 74 and up against the solenoid cores 112. Spring 105 holds the roller 119 on the cam 45.

The signal controlling the indication of a count in an electronic counter is produced by the circuitry shown in FIG. 4, the counter being connected to the coincidence circuits 136. However, the inputs applied to the coincidence circuits 136 can be supplied by other electrical circuits, such as flip-flops operated by photocell pulses. An example of a suitable counter is shown in US. Patent No. 3,029,352 issued April 10, 1962, to C. B. Marshall. The patent discloses four transistor binary flip-flop stages connected in cascade with added circuits to convert to a count of ten to fill and return to the initial condition (adapted to count according to the decimal system). The four flip-flops fli-p at counts of 1, 2, 4, and 8, respectively, i.e., a modified binary 1-2-4-8 counter. The counter is so connected to the coincidence circuits 136 that, when the four [flip-flops flip, positive inputs are applied to leads 137-140, i.e., there is one lead 137-140* for each output of the flip-flops. Combinations of positive and negative leads 137-140 permit counting in the decimal system 0-9. Auxiliary flip-flop circuits similarly provide the required combinations of positive and negative leads 141- 144 to correspond to blank and extra segments of the dual commutator 71.

The following table (Table No. 1) shows the positive or negative condition of the leads 137-.140 according to the count:

Lead 138 Lead 139 Lead 140 In addition, leads 141-144 are for blank ('13), respectively, and are for extra (E), respectively.

The function of the readout device is to position the print wheel 72 in a printing station according to the count in the counter or to B or E (twelve printing positions).

The dual commutator pattern and the cooperation of the brushes 97 (FIG. 3) is shown in the above U.S. application Serial No. 416,526. The commutator 71 needs only one-half a revolution or less to produce a readout. One set of the stationary brushes 97 is connected to leads 147- 151 (FIG. 4) and the other set is connected to leads 152-156 (FIG. 4), both sets being arranged to pick up the same 1-2-4-8 binary coded decimal signals as shown in the table above.

The leads 147-156 are shown connected to the coincidence circuits 136 in FIG. 4. Common commutator leads 147 and 152 are joined at the end of a lead 158 which is connected to a minus 20 volts power supply. Leads 148- 151 are connected to the common lead 147 through contacts 159 and leads 153-156 are connected to the common lead 152 through contacts 160. Actually, contacts 159 and 160 do not exist but are shown only to illustrate how the commutator electrically connects and disconnects the respective leads. Leads 151 and 156 are joined at terminal 161; leads 150 and 155 are joined at terminal 162; leads 149 and 154 are joined at terminal 163; and leads 148 and 153 are joined at terminal 164. Resistors 165 are connected to such terminals 161-164 to provide positive inputs to the coincidence circuits 136 which correspond to the positive inputs provided by the counter leads 137-140.

Opening of contacts 159 in leads 148-151 applies positive inputs from the resistors 165 through the leads 148- 151 to the coincidence circuits 13 6. Opening of contacts in leads 153-156 also applies positive inputs from the resistors through the leads 148-151 to the coincidence circuits 136, because lead-s 148-151 are joined to leads 156-153, respectively. Closing of contacts 159 in leads 148-151 applies negative inputs from the minus 20 volts power supply (lead 158) through the leads 148- 151 to the coincidence circuits 136. Closing of contacts 160 in leads 148-151 applies negative inputs from the minus 20 volts power supply (lead 158) through the leads 148-151 to the coincidence circuits 136, because leads 148-151 are joined to leads 156-153, respectively.

The following table (Table No. 2) shows the positive or negative condition of the leads 148-151 (positive or negative inputs to coincidence circuits) according to which of the commutator segments are at the brushes 97.

Lead 151 Lead 149 Segments Table No. 1 (counts 0-9) and Table No. 2 (segments 0-9) are alike, except the positive and negative input conditions are opposite. Also, the positive and negative input conditions in Table No. 2. for B and E are like such conditions or leads 141-144. For the sake of simplicity, the following description will ignore readout positions B and E, since an understanding of the invention can be had by an understanding of how the print wheel 72 is positioned according to the count in the counter, i.e., counts 0-9.

Any coincidence circuit which matches plus and minus inputs and produces current flow in output leads can be used. When the input on commutator lead 151 is plus and the input on counter lead 137 is minus or vice versa, current flow stops in output lead 166, when the input on commutator lead 150 is plus and the input on counter lead 138 is minus or vice versa, current flow stops in output lead 167, when the input on commutator lead 149 is plus and the input on counter lead 139 is minus or vice versa, current flow stops in output lead 168, and when the input on commutator lead 148 is plus and the input on counter lead 140 is minus or vice versa, current flow stops in output lead 169. Stoppage of current flow in all of the output leads 166-169 indicates coincidence. If there is current flow in any one of the output leads 166- 169, coincidence does not exist. This means, for example, that if the count in the counter is three inputs, see Table No. 1) coincidence occurs when the commutator segments to produce a 3 are at the brushes 97 inputs, see Table No. 2).

If there is current flow in output lead 166 or 167 or 168 or 169 (not at coincidence), then there is current flow in a PNP transistor 170 which has its emitter connected to a minus 7 volts power supply through a lead 171, its base connected to the leads 166-169 through a lead 172, and its collector connected to the base of an NPN transistor 173 and to a resistor 174. A resistor 175 is connected between the lead 172 and ground. When the PNP transistor 170 is on, terminal 176 connected to the collector of the transistor comes to minus 7 volts, the same as that of the power supply on the lead 171. The resistor 174 and a coil 135 of the solenoid 113 (FIG. 3) are connected to a minus 20 volts power supply connected to a terminal 177, the coil 135 also being connected to the emitter of the NPN transistor 173, and the collector of the NPN transistor 173 is connected through a lead 178 to the emitter of the PNP transistor 170. When the PNP transistor 170 is on, the NPN transistor 173 also is on because the base of the transistor 173 (connected to minus 7 volts terminal 176) is more positive than the emitter of the transistor 173 (connected to minus 20 volts terminal 177) and current flows through the coil 135, i.e., the solenoid 113 (FIG. 3) is energized. Thus, the solenoid 113 is energized when coincidence does not exist and is deenergized when coincidence exists (no current flow in any of output leads 166-169-transistors 170 and 173 offno current flow in coil 135).

-In operation, to make a new reading, the gear 43' and the cam 45 are turned through one revolution. Gear 43 drives gear 61 through the intermittent face gears 59 and 60. An instant after the cam 45 starts rotating, the cam following roller 119 moves down into the cam depression 117 causing the reset lever 108 to move down and then back up as shown in FIG. 3 and the latch pawls 75 are driven away from the detent wheel teeth 74 and up against the solenoid cores 112, the solenoids 113 being denergized at this time when successive readouts are alike and being energized at this time when successive readouts are not alike as described hereinafter. The deenergized solenoids 113 (successive readouts alike) permit the springs 100 to return the pawls 75 to the same tooth pockets from which they were removed. The energized solenoids 113 (successive readouts not alike) hold the pawls 75 up out of engagement with the detent Wheel teeth 74.

The rotation of the gear 61 rotates the square shaft 68, which drives the detent wheel clutch 76, an equal amount. The gear ratio between the gears 73 and 91 of the detent wheel 70 and of the commutator 71, respectively, is 1:1. However, the gear ratio between such gear 73 and the gear 86 on the print wheel 72 is 2:1. The direct gearing keeps the commutator 71 and the print wheel 72 synchronized, the printing type 89 on the print wheel corresponding exactly to the segments of the commutator 71 (twenty-four commutator segments and twenty-four detent wheel teeth 74), i.e., for example, when the 2 commutator segments are at the brushes 97, the 2 printing type is located in a printing station ready for printing to be accomplished. Because of the dual commutator pattern, only one-half revolution or less'of the commutator 71 is required for a readout, but, because of the above 2:1 gear ratio, such one-half revolution of the commutator produces a full revolution of the print wheel 72. Of course, less than one-half revolution of the commutator can produce a readout depending on how soon the count in the counter and the commutator segments agree. As the print wheel or rotatable member 72 which is to be positioned according to information in the counter approaches the position corresponding to the information, the coincidence circuits 136 detect coincidence between the commutator position and the count in the counter and all current flow stops in output leads 166-169 and thus in the transistors 170 and 173 and in the coil 135 to deenergize the solenoid 113. Deenergization of the solenoid 113 permits the coil spring 100 to pivot the stopping latch pawl 75 into engagement with the proper one of the twenty-four teeth 74, stopping the detent wheel 70 and thus the commutator 71 and the print wheel 72 in positions wherein the print wheel 72 is positioned in the printing station corresponding to the count in the counter. After the detent wheel 70 is stopped, its clutch drum 77 continues to turn until the square shaft 68 and its gear 61 stop. The readout device includes a series of modules each having a print wheel that indicates the digits of a particular denominational order.

The driver face gear 59 includes a first portion 182 having four peg teeth 179a-d and a locking ring 180 with a cam surface 181 and a second portion 183 having a gear 184 meshed with the gear 43, the gear portions 182 and 183 being connected by means of four tongue and groove connections 185. The driver face gear 59 is rotatably mounted on a stationary shaft 186 extending horizontally from that one of the side plates 22 shown in FIGS. 5 and 6. The driven face gear 60 includes a first portion 187 having eight peg teeth 188a-h and a second portion 189 having a gear 190 meshed with the gear 61, the gear portions 187 and 189 being connected by means of four tongue and groove connections 191. The driven face gear 60 is rotatably mounted on a stationary shaft 192 extending horizontally from the side plate 22. The shafts 186 and 192 carry a plate 193 which in turn carries a switch 194 having a switch operator 195 which is operated by an extension 196 on the second portion 183 of the driver face gear 59. The switch 194 is normally closed but is held open in the home position of the readout device to indicate that the previous reading has been completed.

In operation, to make a new reading, the gear 43 and the cam 45 are turned through one revolution. The gear 43 drives the driver face gear 59 through 360 degrees per cycle. An instant after the cam 45 starts rotating, the cam following roller 119 moves down into the cam depression 117 causing the reset lever 108 to move down and then back up as shown in FIG. 3 and the latch pawl 75 is driven away from the detent wheel teeth 74 and up against the solenoid core 112, the solenoid 113 being deenergized at this time when successive readouts are alike, because the commutator 71 has not been moved enough to produce a new electrical output, and being energized at this time when successive readouts are not alike, because the new count in the electronic counter does not agree with the rotary position of the commutator 71.

The working parts are shown in their home position in FIG. 6. The driver face gear 59, by engagement of the cam surface 181 of its locking ring 180 with the peg tooth 188a, reverses or drives the driven face gear 60 counterclockwise as viewed in FIG. 6 about ten degrees to compensate for the slight movements of the pawl 75, as driven ahead by its spring 100, and of the detent wheel 70, as urged by its spring clutch toward the pawl, when the pawl 75 is lifted clear of the detent wheel 70 at the beginning of a readout cycle. This moves the detent wheel 70 slightly clockwise as viewed in FIG. 3 so that if the readout signal is the same as the preceding one the pawl 75 drops squarely back into the same tooth pocket without danger of catching on the tip of the tooth. When successive readouts are alike, the solenoid 113 remains deenergized to permit the pawl 75 to drop back into the same tooth pocket during a dwell period hereinafter described which follows the above reversal period.

If successive readouts are not alike, the solenoid 113 is energized to hold the pawl 75 out of engagement with the detent wheel 70. At the end of the ten degree reversal, the peg tooth 188a is on a high part 181a of the cam surface 181 and the peg tooth 18% is on a low part 1811) of the cam surface 181. Continued counterclockwise rotation of the driver face gear 59 moves the locking ring 180 between the peg teeth 188a and b on the one side and the peg teeth 1880 and h on the other side, a lock side 197 of the locking ring 180 holding the driven face gear 60 stationary for a dwell of about 125 degrees. After point A on the locking ring 180 meets point B on the peg tooth 18811, the driven gear 60 is driven clockwise in the direction of the curved arrow shown in FIG. 6 for 10 degrees to cancel the 10 degree reversal. This returns the Working parts to their positions shown in FIG. 6. Immediately thereafter, peg tooth 179a on the driver gear 59 engages peg tooth 1880 on the driven gear 60 and tooth drive takes place to advance the driven gear 60 about 225 degrees, i.e., a net 225 degreesdegrees counterclockwise and 235 degrees clockwise. This drives the gear 61 counterclockwise as viewed in FIG. 6 about 190 degrees per cycle. As described above the commutator 71 needs only one-half a revolution or less to produce a readout. As the print wheel 72 approaches the position corresponding to the count in the counter, the solenoid 113 is deenergized and the pawl 75 moves into engagement with a tooth 74, stopping the detent wheel and thus the commutator 71 and the print Wheel 72 in readout position as described above.

The pair of intermittent gears 59 and 60 reverses the detent wheels 10 degrees at the start of a readout cycle and locks the detent wheels during a following dwell period. The readout signal is applied before the detent wheels [are driven ahead. If the readout signal is the same as the preceding one, the pawls drop squarely into their tooth pockets. 'If the readout signal is different from the preceding one, the readout wheels rotate until coincidence is reached between the information in the electrical circuit and the positions of the readout wheels. The intermittent gear pair includes the driver face gear 59 and the driven face gear 60 each including a plurality of peg teeth and the driver gear further including a locking ring, the locking ring engaging peg teeth on the driven gear to lock the driven gear the above dwell part of the cycle and the peg teeth on the driver gear engaging peg teeth on the driven gear to drive the driven gear during the last part of the cycle. The locking ring also includes the cam surface for reverse driving the driven gear during the first part of the cycle. The intermittent gear pair with or without the cam surface can be used in devices other than numerical display devices to provide timing and driving functions, e.g., in printers.

If the numerical display device is constructed of high precision parts and assembled to have little play between working parts, the reversal part of the cycle may be omitted. In a second embodiment shown in FIG. 7, a locking ring 1801 is smoothly curved on both sides so that, as the gear 591" is turned counterclockwise from its position shown in FIG. 7, the locking ring locks the driver gear 601 to provide a dwell period, in the same manner as the first embodiment provides a dwell period, with no reversal occurring. Thereafter, the driver gear peg teeth engage the driven gear peg teeth to rotate the driven gear in the same manner as the first embodiment provides peg teeth gear drive. Similar reference numbers in FIG. 7 refer to parts alike in structure and function to parts shown in FIGS. 1-6.

When the second embodiment (no reversal) of the intermittent gear pair is used in the readout device, the combination includes a rotatable member to be rotated to a readout position corresponding to information in an electrical circuit, i.e., any rotatable member not necessarily a toothed-member, means (intermittent gear pair) for locking the member in a dwell position and later rotating the member, and stopping means operable during said dwell to disengage from and reengage with the member when successive readout positions are alike, and operable when successive readout positions are unlike and after said dwell for stopping the member in the readout position. When the first embodiment (reversal) of the intermittent gear pair is used in the readout device, the combination includes a rotatable member to be rotated in a forward direction to a readout position corresponding to information in an electrical circuit, drive means for reversing the member slightly in a direction opposite to said forward direction and later rotating the member in said forward direction, and stopping means operable after said reversal to be engageable with the member for stopping the'rnember in the readout position.

It is to be understood that the above description is illustrative of this invention and that various modifications thereof can be utilized without departing from its spirit and scope.

Having described the invention, I claim:

1. Intermittent gearing comprising, in combination, a rotatably mounted driver face gear and a rotatably mounted driven face gear each including a plurality of peg teeth and the driver gear further including a locking ring, the locking ring engaging peg teeth on the driven gear to lock the driven gear during part of a rotative cycle of the driver gear and the peg teeth on thedriver gear engaging peg teeth on the driven gear to drive the driven gear during another part of said rotative cycle.

2. Intermittent gearing according to claim 1 wherein the locking ring includes a cam surface for reverse driving the driven gear during still another part of said rotative cycle.

3. A readout device comprising, in combination, a rotatable toothed-member to be rotated to a readout position corresponding to information in an electrical circuit, drive means for locking the toothed-member in a dwell position and later rotating the toothed-member, and stopping means operable during said dwell to disengage from and reengage with a tooth on the toothedmember when successive readout positions are alike, and operable when successive readout positions are unlike and after said dwell for stopping the toothed-memberin the readout position.

4. A readout device according to claim 3 wherein the drive means includes driver and driven face gears.

5. A readout device according to claim 3 wherein each of the gears includes a plurality of peg teeth and the driver gear further includes a locking ring, the locking ring engaging peg teeth on the driven gear to lock the driven gearduring said dwell and the peg teeth on the driver gear engaging peg teeth on the driven gear after said dwell to drive the driven gear to said readout position.

6. A readout device comprising, in combination, a rotatable toothed-member to be rotated in a forward direction to a readout position corresponding to information in an electrical circuit, drive means for reversing the toothed-member slightly in a direction opposite to said forward direction and later rotating the toothedmember in said forward direction, and stopping means operable after said reversal to be ingageable with a tooth on the toothed-member for stopping the toothed-member in the readout position.

7. A readout device according to claim 6 wherein the drive means includes driver and driven face gears.

8. A readout device according to claim 7 wherein each of the gears includes a plurality of peg teeth and the driver gear further includes a ring, the ring engaging peg teeth on the driven gear to drive the driven gear during said reversal and also in said forward direction enough to cancel said reversal and the peg teeth on the driver gear engaging peg teeth on the driven gear after said cancellation to continue driving the driven gear in said forward direction.

9. A readout device according to claim 8 wherein the ring passes between pairs of peg teeth on the driven gear and has a locking surface which prevents rotation of the driven gear during a dwell time which exists between the end of said reversal and the beginning of said cancellation.

10. A readout device comprising, in combination, a rotatable member to be rotated to a readout position corresponding to information in an electrical circuit, means for locking the member in a dwell position and later rotating the member, and stopping means operable during said dwell to disengage from and reengage with the member when successive readout positions are alike, and operable when successive readout positions are unlike and after said dwell for stopping the member in the References Cited readoutposltwn- UNITED STATES PATENTS I f g i g f fii l 498,552 5/1893 Hunt et a1 7463 ro aa e mem er 0 e ro ae in a orwar me 1011 0 2,896,845 7/1959 Hansen etaL a readout position corresponding to information in an 5 3 301097 1/1967 Beman electrical circuit, drive means for reversing the member slightly in a direction opposite to said forward direction FRED C. MATTERN, JR., Primary Examiner.

and later rotating the member is said forward direction, JAMES AWONG Assistant Emmi-net and stopping means operable after said reversal to be engageable with the member for stopping the member in 10 the readout position. 74-412 US. Cl. X.R.

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