US2311193A

US2311193A - Interlock mechanism

Info

Publication number: US2311193A
Application number: US416600A
Authority: US
Inventors: David S Willson
Original assignee: WOOD JOHN Manufacturing CO Inc
Current assignee: JOHN WOOD MANUFACTURING COMPANY Inc; WOOD JOHN Manufacturing CO Inc
Priority date: 1941-10-25
Filing date: 1941-10-25
Publication date: 1943-02-16
Anticipated expiration: 1960-02-16

Description

Feb. 16, 1943. v D. s. WILLSQN v I 2,311,193 I INTERLOCK MECHANI'SM Filed oct. 25; 1941 2 Sheets-Sheet 1 FIG I.

Feb. 16, 1943. I D. s.4 wn i soN Y 9 I INTERLOCK MECHANISM 'Filed 001; 25, 1941 I 2 Sheets-Sheet 2 nwqS. VI 144501 By Patented Feb. 16, 1943 David S. Willson,

.Muskegon' Heights, Mich, as-

signor to John Wood Manufacturing Company, Inc., Philadelphia, Pa.,

ware

Application October 25, 1941, serial No. 416,600

9 Claims.

My invention relates to interlock mechanisms particularly applicable for use in fluid dispensing pumps. My improved interlock mechanism is adapted to be operatively connected to the re'- setting shaft of the clock indicating mechanism of a pump and is connected in controlling relation to the motor switch of the pump motor.

One object of my invention is to provide an interlock which is compact, sturdy, simple, and inexpensive to manufacture.

Another object of my invention is to provide an interlock mechanism which prevents the resetting of the pump indicating means when the motor switch is closed.

Another object of my invention is to provide an interlock mechanism' vvhi ch necessitates the resetting of the indicating mechanism to zero position before the motor switch can he moved to closed position.

My invention includes the various novel features of construction and arrangement hereinafter more definitely specified;

Fig. I is a fragmentary vertical sectional view of a'flui'd dispensing apparatus ofa conventional type and showing my improved interlock mechanism connected both to the set-back shaft of the pump indicating mechanism and to the motor switch operating mechanism.

FigII' is a vertical sectional view of the interlock mechanism shown in Fig. I, taken on the lines'II. II in'Fig. III. I p I Fig. III is avertical'sectional view of the interloci-i mechanism" shown in Fig. I, taken on the lines III; III in Fig. II. Fig. IIIshowsthe mechanism in the position it assumeswhen the indicating mechanism has been reset" to zero position and with the pump motor switch in open position. Y I

Fig. IV is" a partial vertical sectional view of the mechanism shown in Fig. III, but with the switch lever'moved'topositionto close the motor switch. V e

Fig. V is a partial vertical sectional view of the mechanism shown in Figi III, and'with the switch lever moved partially'to' open themotor switch.

, Fig. VI is' a partial'vertioal sectional view of the mechanism shown in Fig. 1H, and in the position which it assumes when the s'witchlever is fully mbved with the motor switch opened, but before resetting" of' the pump indicating mechanismi V i 1 Fig; VII is a partial elevation of the shaft and cam'a sseriit ly'shown in Fig II. I v p N Fig; VIIIis anelevationofthe cam disk shown at the left hand side of'FigiVII.

a corporation of Dela- Fig. IX is anelevation of the intermediate cam disk shown Fig VII Fig. X is an evatiori of disk shown in Eig V II. H A v n Fig. XI is a perspective view of the locking dog shown in Figs. II to VIinclusive. 7

Fig. XII is an elevation of the locking pawl for a s wn in Ei Referring to Fig. L the interloclrmechanism, generally indicated by the reference' niarl l is m u on the br qk .Zwhi ..1 ,l Y e r. tened to h o pin v etoih me. iih o u ca ing. ss eism. vi. the li id e s n avts eerallyg im tated. by. the reference marl; 5. The computing clock indicating mechanism shown in lifig. I is of the type shown and described injLetterslf'atent o f the United States No. 2,151,239 granted March 21, 1939, to l ee Said liquid dispensingapparatus chosen for illustration is the well-known computing pump and includes the housing 1;

chassis frame members

8 and 9; and dispensinghosegliflflwhich'has at its distal end the dispensing nozzle ll. The nozzle llj isof thewell-known conventional type and includes a valve under control of the manually operative pivoted lever l3 when the n ozzle I l is not in use,.it is placed by the operator in the nozzle boot I4; formed in the side off the housing I, and ispositioned on the bracket l5 rigidl mounted onthe frame member .9; when the nozzle H 's' positioned in the housing,.a s shown in Fig. I, the weight of the nozzle rests on the right hand end of the switch lever 16 which is pivotally mounted at Hon the bracket l8 rigidlycon'nected' to' the side framelmember 9. Saidpivo-tedjsw'itch lever I6 includes'the arm 19 which is pivotally connected t'o'the depending link 26, the distal en'd'of' which is connected in operating relation'to the electric switch controlling the pump, motor. Clockwise movement of the pivoted arm It causes the motor switch to be moved. to off positiongandcounterclockwise movement of the pivoted arm lficauses the motor switch to' be moved'ito o'njf orjclosed, position. Said computing clock mechanism includes the shaft 22' by which the gallons indicating wheels and the dollar value indicating wheels ar contemporaneously reset to zero position by manual operation of the crank 23 which extends beyond the right hand cam the housing and is connected to the setback shaft 22, conveniently by the shaft" 25' and link 25, theiopposite ends of which link 25 are respectively connected tojthelshafts 22 24. The shaft 24 is' conveniently supported" in the bracket 26 which is rigidly connected to the frame member 8 and the top of the variator housing 3.

As best shown in Fig. II, the interlock mechanism is enclosed in the casing 28 which is provided with the cap member 29, conveniently rigidly fastened to the casing 28 by a series of screws 39. The interlock mechanism includes the shaft 3|, the right hand end of which is journaled in the bearing sleeve 33 which is press-fitted in the opening 34 formed in said casing 28. Said shaft 3| is provided at its left hand end with the enlarged portion 36 which is journaled in the bearing sleeve 31 press-fitted into the opening 38 formed in the cap member 29. The enlarged head 39 of the shaft 3| has the slot 39 which forms the coupling member 40 which is driven by a corresponding coupling member 42, of the computer setback shaft 22, conveniently by means of the drive link 43, the opposite ends of which respectively engage the coupling members 49 and 42. Thus, rotation of the crank 23 will cause rotation of the computing clock setback shaft 22 and corresponding rotation of the interlock mechanism shaft 3|. Accordingly, when the interlock mechanism assumes a position, hereinafter described, in which rotation of the interlock shaft 3| is prevented, it is impossible for the operator to turn the crank 23 to effect rotation of the indicating mechanism setback shaft 22.

The shaft 3| has at its left hand end an enlarged portion forming the shoulder 44 which has diametrically opposite flattened sides 45. The spring post retainer disk 46 is provided with an axial opening corresponding to the configuration of the flattened sided shaft shoulder, and said disk 46 is push-fitted on said shoulder 44 and turned with said shaft 3|. Said disk 46 carries the spring post 41, which is conveniently rigidly connected to said disk 46 by riveting over the reduced left hand end portion 48 of said post 41 in the opening 49, of the disk 46, into which the reduced portion extends.

One end of the torsion spring 59, wound counterclockwise in Fig. III, encircles and is fastened to the post 41 of the disk 46. The opposite end of said torsion spring 59 is fastened by a hook to an opening formed in the enlarged hub portion 52 of the sleeve 53 which is mounted for freedom of turning movement on the shaft 3|. Said sleeve 53 has the reduced annular portion 54 provided with diametrically opposite flattened sides 55. The cam disk 51 is provided with an axial opening corresponding to the configuration of the flattened sided reduced portion 54 of the sleeve 53, and said cam disk 51 is push fitted and riveted on said sleeve 53 and turns therewith.

As shown in Fig. VIII, said cam disk 51 is provided with the notched recess 58 and a cam surface 59 of a lesser diameter than the diameter of the cam surface 69. The junction of said cam surfaces 59 and 69 forms the shoulder 9| in the periphery of said cam 51.

Said cam disk 51 is provided with the pin 63 which is conveniently rigidly connected to said disk 51 by riveting over the reduced left hand end portion 64 of said pin 63 in the opening 65, of the cam disk 51, into which the reduced portion 64 extends.

The shaft 3! has rigidly mounted thereon the sleeve 61 which is fastened to the shaft 3| conveniently by means of the p n 53 eXtending through said sleeve and shaft. Said sleeve 51 is provided with the reduced portion 19, the intermediate portion 1|, and the enlarged portion 12.

Said reduced portion 19 is provided with diametrically opposite flattened sides and has rigidly mounted thereon the cam disk 15 provided with an axial opening corresponding to the configuration of the reduced portion 10. Said cam 15 is push fitted and riveted on said shoulder 19 and turned with said sleeve 61 pinned fast to the shaft 3|, as above described.

Said cam disk 15 ha the notched recess 15, the cam surfaces 11 and 19 of the same diameter, and the cutaway surface 19 of lesser diameter than the cam surfaces 11 and 18. The junction of the

surfaces

19 and 11 forms the shoulder 89 and the junction of the

surfaces

19 and 13 forms the shoulder 8| in the periphery of the cam 15. The pin 63 is positioned in the outer portion of the cam disk 51 so that it is presented in the same path of travel of the shoulder 99 of the cam disk 15. Thus, the disk 51 is permitted to rotate under spring loading within limits defined by the pin 63 and the shoulders 89 and 8| of the disk 15, as hereinafter described in detail.

The cam disk 15 carries the pin 83 which conveniently is rigidly connected to said disk 15 by riveting over the reduced left hand end portion 84 of said pin 83 in the opening 85, of the disk 15, into which the reduced portion 84 extends. Said pin 83 extends into and through the arcuate slot 81 of the cam disk 88 which is mounted to turn freely on the intermediate shoulder 1| of the sleeve 61. Said shoulder 1| has mounted thereon and in axial alinement therewith the spacing ring 90 which is positioned between the disk 15 and the disk 88. As best shown in Fig. X, said cam disk 83 is provided with the notched recess 92 and with the peripheral notch 93.

The screw stud shaft 91, provided with the enlarged head 98, is rigidly mounted in the boss 99 formed in the lower part of the casing 28, and said stud shaft 91 has the screw threaded portion I 99 engaging the opening I 9| formed in said boss 99. Said stud shaft 91 is conveniently rigidly clamped in said housing 28 by engagement of the nut I92 with the screw threaded end I99 of said shaft 91. The lockout dog I95, having the two arms I99 and I91, is mounted with freedom of turning movement on the stud shaft 91. As best shown in Fig. III, said lockout dog I95 is continually stressed counterclockwise in Fig. III by the spring I99, one end of which extends through an opening in and is fastened to the arm I96 and the opposite end of said spring I99 encircles and is rigidly connected to a stud II9 rigidly mounted in the boss III formed in said casing 28. As shown in Figs. II and III, the arm I96 includes at its end the hook portion I I2 which is presented in the path of and adapted to engage the shoulder 6| in the periphery of the cam disk 51. As best shown in Figs. III and XI, the other arm I01 of the lockout dog is provided with the ear II3 adapted to be engaged by the lower arm II 5 of the throw-out arm II6 which is pivotally mounted on the shaft 3| with freedom of turning movement.

Said stud shaft 91 also has pivotally mounted thereon, with freedom of turning movement, the index pawl I29, the pointed end I2I of which is adapted for latching engagement with the notch 93 of the cam disk 88, as hereinafter described. Said index pawl I29 is continually stressed counterclockwise by means of the spring I22, one end of which is fastened to said index pawl I29, as at I23, and the opposite end of said spring encircles and is fastened to said stud shaft I I0. As best shown in Fig. II, I find it convenient to provide the spacing ring I25 between the hook arm member I06 of the lookout dog I and the index pawl I20, and to provide the spacing washer I26 between the index pawl I20 and the arm I01 of the lockout dog I05.

The cam lever I30 is pivotally mounted on the screw stud shaft I3I which has the enlarged slotted head I32 and screw threaded portion I33. Said stud shaft I3I is rigidly mounted by means of the nut I36 and lock Washer I31 in an opening I34 formed in the boss I35 at the upper portion of the casing 28. As shown in Fig. III, said lever I30 carries the locking block I30 which is rigidly connected to the lever I30 conveniently by the rivets I39 and I40. Said lever I30 is provided with the extension face I4I adapted to engage the upper arm I I1 of the throw-out arm I I6 when the lever I30 is moved clockwise, in Fig. III, to motor switch closing position. Clockwise movement, in Fig. III, of said throw-out arm is limited by the lower arm II5 coming into engagement with the stud II8 rigidly mounted in the casing 28.

The lever I35 includes the arm I43 which extends through the slotted opening I44 formed in the upper part of the casing 28. The arm I43 is provided at its outer end with the opening I45 in which is engaged the upper end of the rod I46. Said rod I46 is provided at its lower end with the adjustable coupling member I43, the lower end of which is connected by a ball and socket joint to the member I50 which is rigidly clamped to the switch lever rod 20, conveniently by means of the screw I5I and nut I52, as shown in Fig. I.

Operation My improved interlock mechanism operates as follows:

Assuming that the indicating mechanism has been reset to zero and the motor switch is in off position with the nozzle II positioned on the bracket I5 and switch lever I6, as shown in Fig. I; the operator removes the nozzle from the nozzle bracket and switch lever I6 and manually moves the switch lever I6 counterclockwise, in Fig. I, to close the motor switch. The previously performed resetting operation has caused the notched recesses 58, 16, and 92 of their respective cam disks 51, 15, and 88 to be brought into alinement. Said cam disks 51, 15, and 08 are shown in Figs. VIII, IX, and X in the relative positions which the disks assume at the end of the resetting operation. In such position wherein the

notohed'recesses

58, 16, and 92 are in alinement, the hook arm I06, of the lookout dog I05, is in latching engagement with the shoulder 6I in the periphery of the cam 51, and the pointed end I2I of the index pawl I20 is in latching engagement with the notch 03 of the cam disk 88.

Counterclockwise movement of the switch lever I6 with its integral arm I9 causes the rod 20 to be moved downwardly in Fig. I. Such downwardl movement of the rod 20 causes the rod I46, connected to the rod 20 by the member I50, also to be moved downwardly, thereby causing the cam lever I30, connected to the upper end of the rod I45, to be moved clockwise in Fig. III. Clockwise movement of the lever arm I30 pivotally about its stud shaft I3I, brings the locking block I38, carried by said lever I30, into registry with the alined notched recesses 58, 16, and 92 of the cam disks 51, 15, and 86. When the looking block I38 has moved partially into the alined notched recesses, 58, 16,.and 9,2, andthe mechanism is in the position shown in Fig. III, the extension face I4I of the cam lever I30 is brought into engagement with the upper arm II1 of the throw-out arm I I6. Continued movement of the cam lever arm I30 toward switch closing position moves the throwout arm H6 counterclockwise, in Fig. III, causing its lower arm H5, in contact with the ear II3 of the lookout dog I05, to move the lockout dog I05 clockwise, thereby causing the hook arm I06 to be moved out of latching engagement in the notch 6| of the cam 51. The cam disk 51, thus freed from the restraining engagement of the hook arm I06, is now free to rotate, under spring loading of the torsion spring 50, counterclockwise as in Figs. III and IV, but only to the extent represented by the difference. between the dimensions of the notch 58 and the locking block I35, because the locking block I38 is still in the position shown in Fig. IV, with the motor switch closed.

When the operator has terminated the dispensation of fluid through the nozzle II by releasing the nozzle lever IS, the operator moves the motor switch to off position by clockwise movement of the switch lever I6, effected either manually or by the placing of the nozzle II on the outwardly extending arm of said lever I6. Clockwise movement of the switch lever I6 causes the rod 26, and the rod I45 connected thereto, to be moved upwardly, in Fig. I, thereby causing the cam lever I30 to be moved counterclockwise in Figs. IV and V. The first part of such counterclockwise movement of the lever arm I30 moves the locking block I30 out of detaining engagement in the notched recess. 58 of the cam disk 51, but not out of engagement with the

notches

16 and 92 in the cam disks 15 and 88, and the cam disk 51 is permitted to rotate counterclockwise under spring loading of its torsion spring 50 until its rotation is arrested by the shoulder Si, in the periphery of the cam 51, coming intoengagement with the locking block I38. Fig. V shows the position of the interlock parts in the position just described. It is to. be noted that with counterclockwise movement of the cam lever I35 to such extent, the motor switch is still in on position and slight additional counterclockwise movement of the cam lever I30 is necessary in order to eifect movement of the motor switch to oii position. However, the operator cannot move the switch leverclockwise when the parts have asumed the position shown in Fig. V, without first moving the motor switch to off position and fully completing the resetting operation, because such automatic partial counterclockwise rotation of the cam 51, under the spring loading of its torsion spring 55, has presented the cam surface 59 of the cam 51 into the path of the locking block I33 of the cam lever I30, thus preventing any clockwise movement of the lever I30.

Continued counterclockwise movement of the cam lever I30, effected by means of clockwise operation of the switch lever I6, not only frees the locking block I30 from engagement with the notch of the cam 51, but contemporaneously moves said locking block out of engagement with the notched recesses 16 and 62 in the other cam disks 15 and 88. Upon disengagement of the locking block I36 from the notch 6| of the cam 51, said cam 51 is further rotated under spring loading of its torsion spring 50 until the pin 63 comes into engagement with the shoulder 00 formed by the juction of the

surfaces

19 and 11 of the cam 15 which is. pinnedfast. to the shaft 3 I. The interlock parts are shown in Fig. VI in the position just above described, with the motor switch open and the cam lever I30 moved to the full extent of its counterclockwise movement, but with the resetting of the clock not initiated.

The operator then resets the indicating mechanism to zero position by clockwise movement of the setback crank 23, which causes corresponding movement, not only of the indicating mechanism setback shaft 22, but also of the interlock shaft 3! which is directly connected by the coupling link 43 to said setback shaft 22. The direction of rotation to effect such resetting operation would be counterclockwise, as the shaft Si is viewed in Fig. III. The cam disk 15 being rigidly mounted on the shaft 3! and the shaft 3| in turn being turned contemporaneously with the turning of the setback crank 23, said cam disk 15 is positively rotated counterclockwise by rotation of the cam 23.

Such counterclockwise rotation of the shaft 3I and cam disk 15 causes the cam disk 88 also to be turned counterclockwise because of the engagement of the pin 33, carried by the cam 15,

with the end of the arcuate slot 81 in said cam 8B. The cam 51 is also moved counterclockwise by such counterclockwise movement of the shaft 3I, because the torsion spring 50 is connected at one end of the cam disk 51 and at its other end to the disk 46, which disk 46 is rigidly con nected to the shaft 3 I.

Thus, the shaft 31 and the three cams 51, 15, and 88 are rotated as a unit until the shoulder 6| of the cam 51 arrives in position to be engaged by the hook arm I06 of the lockout dog I55. The hook arm I06 rides on the periphery 60 of the cam 51 until the notched recess 58 of the cam 51 is reached, at which point the spring I09 moves the lockout dog I counterclockwise in Fig. III. However, such counterclockwise movement of the dog I415 is limited to prevent said hook arm I06 from engaging the shoulder formed at the junction of the notch 53 and the cam surface 59, by the extension arm I01 coming into engagement and riding on the enlarged portion 12 of the sleeve 61 to maintain the hook arm I86 in a position in which it is just out of the path of the surface 59. Continued counterclockwise rotation of the shaft 31', by continued turning movement of the setback crank 23, brings the shoulder 6I of the cam 51 into engagement with the hook arm I 06, thereby arresting further turning movement of the cam 51. In such arrested position, the notch 53 of the cam 51 is lined up in position to be engaged subsequently by the locking block I38 of the cam lever I 33. counterclockwise movement of the shaft 3| thereafter produces counterclockwise movement only of the cam disks 15,

88, and the disk 48, movement of the latter effecting a loading of the torsion spring 50, one end of which is connected to the disk 46 and the other end of which is connected to the cam disk 51 held stationary by the hook arm I06, as above described.

It is to be noted that the setback shaft 22 of the type of indicating mechanism shown in Fig. I cannot be turned continuously, as described in said Slye et al. Patent No. 2,151,239. The indicating mechanism illustrated is so constructed that the setback shaft 22 can turn only approxi mately 45 more than a complete revolution, at which point further turning movement is prevented. Upon release of the setback crank 23 by the operator, the setback shaft 22 is turned .under spring action in the indicating mechanism to a stopping point which is equivalent to one complete revolution of 360 from the start of the setback operation. As stated in said Slye et al. Letters Patent No. 2,151,239, the purpose of such overthrow motion is to assure a correct lining up of the number of wheels of the indicating mechanism at zero position.

Thus, counterclockwise rotation of the cams 15 and 88 continues until further movement of the setback crank 23 by the operator is prevented by the operation of the elements of the indicating mechanism. The cam disk 88 tends to hang back because the index pawl I20 rides on the periphery of the cam 88. Just prior to the time when the indicating mechanism has reached the end of its maximum travel, the index pawl I20 drops into latching position with the notch 93 in the periphery of the cam 88. With the pointed end I2I of the index pawl I20 in the notch 93 of the cam 88, when the crank 23 is carried slightly farther and thereafter returned automatically by the clock mechanism when the crank 23 is released by the operator, the cam disk 88 is held in position wherein its notched recess 92 is in alinement in the path of travel of the locking block I38 of the cam lever I30.

When the operator releases the setback crank 23, the arcuate slot 81 of the cam 88 permits the cam 15, with its pin 83 extending through said slot 81, to reverse its previous direction of rotation, and move clockwise, by automatic operation of the indicating mechanism, to the extent of the overthrow.

Thus, the notched recesses 58, 1B, and 92 of their respective cams 51, 15, and 88 again are in alined position in the path of travel of the cam block I38 of the cam lever I30 by reason of the fact that the hook arm I05 assures the proper alinement of the notch 58 of the cam 51; the notched recess 16 of the cam 15 is properly positioned because said cam is rigidly fastened to the shaft 3I connected directly to the setback shaft 22; and the pointed end I2I of the index pawl I20 in latching engagement with the notch 93 of the cam disk 88 assures that the notch 92 of said cam disk 88 is likewise in proper position.

The type of indicating mechanism shown may be recycled over and over again, as described in said Slye et al. Patent No. 2,151,239, by operation of th setback crank. Accordingly, if the operator should again recycle the clock mechanism after the indicating wheels have been restored to zero position and no closure of the motor switch has been effected since a previous recycling, my improved interlock mechanism goes through the first part of the cycle of operation as hereinabove described, but of course the hook arm I00 of the lockout dog I05 has not been thrown out of engagement with the notch 0| of the cam 51 because the cam lever I30 would remain unmoved from its uplifted position in which the motor switch is off. Under such circumstances, when the operator has turned the setback crank 23 approximately 55 to 60, the pin 83, carried by the cam 15, comes into engagement with the upwardly extending arm I01 of the lockout dog I05 and causes the lockout dog I05 to be moved clockwise, in Fig. III, to throw the hook arm I03 out of its latched engagement with the notch GI of the cam 51. As shown in Fig. VII, the pin 83 extends through the arcuate slot 81 to a sufiicient extent so as to be presented during its course of travel in the plane of the arm I01 of the lookout dog I05.

It is to be noted from the foregoing description of operation that my improved interlock mechanism has the following functional features of operation:

' First.--If the motor switch has been moved to on and then to off position, the motor switch cannot be moved again to closed position by the operator until the clock indicating mechanism has been reset to zero position, because the notched recesses 58, 1B, and 92 of the respective cams 51, I5, and 88 are brought into alinement to receive the locking block I38 only when the clock indicating mechanism has been ZGIOiZGd subsequent to the last cycle of turning the motor switch to off position. v

Second.-Upon closure of the motor switch and reverse movement thereafter of the cam lever I30 to an extent slightly greater than the position shown in Fig. V which moves the motor switch to open position, the operator cannot again close the motor switch without a recycling of the indicating mechanism, because movement of the cam lever I33 to the extent indicated in Fig. V causes the cam surface 59 of the cam El to be presented as an impedance preventing such clockwise movement of the cam lever E30 as would be necessary to close the motor switch.

Third.-The clock mechanism cannot be recycled by the operator when the motor switch is closed, because the cam 15 is rigidly connected to the shaft 3! which, in turn, is connected directly to the setback shaft 22 and crank 23, and the locking block Q38 of the cam lever I30 is positioned in the notch 16 of said cam 75 when the motor switch is closed, thereby preventing movement by the operator of the setback crank 23 and setback shaft 22. v

It is to be noted that when my improved mechanism is operated in the normal manner and when the spring loaded cam disk 51 is tripped by turning the motor switch to on position by movement of the pivoted lever {B into the alined notches of the cams, the shock of the spring loading of the cam 51 is taken up by the locking block I38 of the cam lever I30 in two steps. lhe first step is when the side of the notch 58 snaps against the locking block I38, and the second step is when the surface of the notch Bl comes into engagement with said locking block I38. After the cam 51 is released from this latter position, the spring loading of the cam disk 51 is substantially expended and said cam disk 51 travels but a short distance before its pin 63 comes into contact with the notched surface of the cam 15. Thus, before engagement of the pin 63 with the cam 15, thespring loading of the cam 5'! has been very, considerably reduced, as well as the amount of travel, so that at such point its kinetic energy is comparatively small.

Data collected has shown that the operator of the type of liquid dispensing apparatus for which my invention is particularly applicable will unnecessarily recycle the indicating mechanism after a previous cycling and without closure of the motor switch perhaps not more than fifty times in a year, and in all probability no more than that number of times during the life expectancy of ten years or more of the apparatus. Tests made on my improved interlock mechanism have demonstrated that its operation remains unimpaired after as many as 35,000 continuous cycling operations, even if the mechanism be subjected to extreme shock by reason of the tripping of the hook arm IE6 by the pin 33 coming in contact with the arm extension Hl'l, instead of said lockout dog being tripped in the normal nected in operating relation manner, and the spring load of the disk 51 being taken up in two steps, as above described.

However, I do not desire to limit myself to the precise details of construction and arrangement herein set forth, as it is obvious that various modifications may be made therein without departing from the essential features of my invention, as defined in the appended claims.

I claim:

1. In interlock mechanism adapted to be connected in operating relation both to the resetting means of the indicating mechanism of liquid dispensing apparatus and to an electric switch controlling the electric motor of said liquid dis-,. pensing apparatus; the combination with a shaft operatively connected to said resetting means; of a first cam rigidly mounted on said shaft and turned therewith; a second cam mounted for freedom of turning movement on said shaft; means carried by said first cam for effecting rotation of said second cam; a third cam mounted for freedom of turning movement a disk rigidly mounted on said shaft; a torsion spring, having one end connected to said disk and the other end to said third cam; a notched recess in each of said three cams; means effecting alinement of said three notched recesses when the indicating mechanism is moved to initial, or zero, position; a lever operatively connected in controlling relation to said electric switch; a cam block carried by said lever for engagement in said three notches when alined; whereby said lever may be moved to switch closing position only when said cam block is in engagement with said three alined cam notches; and means effecting movement of said cams into non-alining carn notch position upon movement of said lever from switch closing to switch opening position.

2. In interlock mechanism adapted to be connected in operating relation both to the resetting means of the indicating mechanism of liquid dispensing apparatus and to an electric switch controlling the electric motor of said liquid dispensing apparatus; the combination with a shaft operatively connected to said resetting means;

of a first cam rigidly mounted on said shaft and turned therewith; a second cam mounted for freedom of turning movement on said shaft; means carried by said first cam for effecting rotation of said second cam, including a pin carried by said first cam in engagement with an arcuate slot formed in said second cam; a third cam mounted for freedom of turning movement on said shaft; a disk rigidly mounted on said shaft; a torsion spring, having one end connected to said disk and the other end to said third cam; a'notched recess in each of said three cams; means eifecting alinement of said three notched recesses when the indicating mechanism is moved to initial, or zero, position, including a locking dog adapted to engage a notch in the periphery of said third cam and an index pawl adapted to engage a notch in said second cam; a lever operatively connected in controlling relation to said electric switch; a cam block carried by said lever for engagement in said three notches when alined; whereby said lever may be moved to switch closing position only when said cam block is in engagement with said three alined cam notches; and means effecting movement of said cams into non-alin ing cam notch position upon movementof said lever from switch closing to switch opening position.

3. In interlock mechanism adapted to be conboth to the resetting on said shaft;

means of the indicating mechanism of liquid dispensing apparatus and to an electric switch controlling the electric motor of said liquid dispensing apparatus; the combination with a shaft operatively connected to said resetting means; of a first cam rigidly mounted on said shaft and turned therewith; a second cam mounted for freedom of turning movement on said shaft; means carried by said first cam for effecting rotation of said second cam; a third cam mounted for freedom of turning movement on said shaft; a disk rigidly mounted on said shaft; a torsion spring, having one end connected to said disk and the other end to said third cam; a notched recess in each of said three cams; means effecting alinement of said three notched recesses when the indicating mechanism is moved to initial, or zero, position; a lever operatively connected in controlling relation to said electric switch; a cam block carried by said lever for engagement in said three notches when alined; whereby said lever may be moved to switch closing position only when said cam block is in engagement with said three alined cam notches; and means effecting movement of said cams into non-alining cam notch position upon movement of said lever from switch closing to switch opening position, including a cam surface formed on said third cam to prevent said lever from movement to closed position.

4. In interlock mechanism adapted to be connected in operating relation both to the resetting means of the indicating mechanism of liquid dispensing apparatus and to an electric switch controlling the electric motor of said liquid dispensing apparatus; the combination with a shaft operatively connected to said resetting means; of a first cam rigidly mounted on said shaft and turned therewith; a second cam mounted for freedom of turning movement on said shaft; means carried by said first cam for effecting rotation of said second cam, including a pin carried by said first cam in engagement with an arcuate slot formed in said second cam; a third cam mounted for freedom of turning movement on said shaft; a disk rigidly mounted on said shaft; a torsion spring, having one end connected to said disk and the other end to said third cam; a notched recess in each of said three cams; means effecting alinement of said three notched recesses when the indicating mechanism is moved to initial, or zero, position, including a locking dog adapted to engage a notch in the periphery of said third cam and an index pawl adapted to engage a notch in said second cam; a pivoted lever operatively connected in controlling relation to said electric switch; a cam block carried by said lever for engagement in said three notches when alined: whereby said lever may be moved to switch closing position only when said cam block is in engagement with said three alined cam notches; and means effecting movement of said cams into non-alining cam notch position upon movement of said lever from switch closing to switch opening position, including a cam surface formed on said third cam to prevent said lever from movement to-closed position.

5. In interlock mechanism adapted to be connected in operating relation both to the resetting means of the indicating mechanism of liquid dispensing apparatus and to an electric switch controlling the electric motor of said liquid dispensing apparatus; the combination with a shaft operatively connected to said resetting means; of

a first cam rigidly mounted on said shaft and turned therewith; a second cam mounted for freedom of turning movement on said shaft; means carried by said first cam for effecting rotation of said second cam; a third cam mounted for freedom of turning movement on said shaft; a disk rigidly mounted on said shaft; a torsion spring, having one end connected to said disk and the other end to said third cam; a notched recess in each of said three cams; means effecting alinement of said three notched recesses when the indicating mechanism is moved to initial, or zero, position; a lever operatively connected in controlling relation to said electric switch; a cam block carried by said lever for engagement in said three notches when alined; whereby said lever may be moved to switch closing position only when said cam block is in engagement with said three alined cam notches; and means effecting movement of said cams into non-alining cam notch position upon movement of said lever from switch closing to switch opening position, including a pivoted throw-out arm actuated by movement of said lever and adapted to disengage said locking dog from engagement with said third cam when said lever is moved to switch closing position.

6. In interlock mechanism adapted to be connected in operating relation both to the resetting means of the indicating mechanism of liquid dispensing apparatus and to an electric switch controlling the electric motor of said liquid dispensing apparatus; the combination with a shaft operatively connected to said resetting means; of a first cam rigidly mounted on said shaft and turned therewith; a second cam mounted for freedom of turning movement on said shaft; means carried by said first cam for effecting rotation of said second cam; a third cam mounted for freedom of turning movement on said shaft; a disk rigidly mounted on said shaft; a torsion spring, having one end connected to said disk and the other end to said third cam; a notched recess in each of said three cams; means effecting alinement of said three notched recesses when the indicating mechanism is moved to initial, or zero, position; a lever operatively connected in controlling relation to said electric switch; a cam block carried by said lever for engagement in said three notches when alined: whereby said lever may be moved to switch closing position only when said cam block is in engagement with said three alined cam notches; and means effecting movement of said cams into non-alining cam notch position upon movement of said lever from switch closing to switch opening position, including a pivoted throw-out arm actuated by movement of said lever and adapted to disengage said locking dog'from engagement with said third cam when said lever is moved to switch closing position, and a cam surface formed on said third cam to prevent said lever from movement to closed position.

7. In interlock mechanism adapted to be connected in operating relation both to the resetting means of the indicating mechanism of liquid dispensing apparatus and to an electric switch controlling the electric motor of said liquid dispensing apparatus; the combination with a shaft operatively connected to said resetting means; of a first cam rigidly mounted on said shaft and turned therewith; a second cam mounted for freedom of turning movement on said shaft; means carried by said first cam for effecting rotation of said second cam, including a pin carried by said first cam in engagement with an arcuate slot formed in said second cam; a third cam mounted for freedom of turning movement on said shaft; a disk rigidly mounted on said shaft; a torsion spring, having one end connected to said disk and the other end to said third cam; a notched recess in each of said three cams; means effecting alinement of said three notched recesses when the indicating mechanism is moved to initial, or zero, position, including a locking dog adapted to engage a notch in the periphery of said third cam and an index pawl adapted to engage a notch in said second cam; a lever operatively connected in controlling relation to said electric switch; a cam block carried by said lever for engagement in said three notches when alined; whereby said lever may be moved to switch closing position only when said cam block is in engagement with said three alined cam notches; and means effecting movement of said cams into non-alining cam notch position upon movement of said lever from switch closing to switch opening position, including a pivoted throw-out arm actuated by movement of said lever and adapted to disengage said locking dog from engagement with said third cam when said lever is moved to switch closing position.

8. In interlock mechanism adapted to be connected in operating relation both to the resetting means of the indicating mechanism of liquid dispensing apparatus and to an electric switch controlling the electric motor of said liquid dispensing apparatus; the combination with a shaft operatively connected to said resetting means; of a first cam rigidly mounted on said shaft and turned therewith; a second cam mounted for freedom of turning movement on said shaft; means carried by said first cam for effecting rotation of said second cam, including a pin carried by said first cam in engagement with an arcuate slot formed in said second cam; a third cam mounted for freedom of turning movement on said shaft; a disk rigidly mounted on said shaft; a torsion spring, having one end connected to said disk and the other end to said third cam; a notched recess in each of said three cams; means effecting alinement of said three notched recesses when the indicating mechanism is moved to initial, orvzero, position, including a locking dog adapted to engage a notch in the periphery of said third cam and an index pawl adapted to engage a notch in said second cam; a lever operatively connected in controlling relation to said electric switch; a cam block carried by said lever for engagement in said three notches when alined; whereby said lever may be moved to switch closing position only when said cam block is in engagement with said three alined cam notches; and means effecting movement of said cams into non-alining cam notch position upon movement of said lever from switch closing to switch opening position, including a pivoted throw-out arm actuated by movement of said lever and adapted to disengage said locking dog from engagement with said third cam when said lever is moved to switch closing position, and a cam surface formed on said third cam to prevent said lever from movement to closed position.

9. In interlock mechanism adapted to be connected in operating relation to the resetting means of the indicating mechanism of liquid dispensing apparatus and to an electric switch controlling the electric motor of said liquid dispensing apparatus; the combination with a shaft operatively connected to said resetting means; of a first cam rigidly mounted on said shaft and turned therewith; a second cam mounted for freedom of turning movement on said shaft; means carried by said first cam for effecting rotation of said second cam; a third cam mounted for freedom of turning movement on said shaft; a torsion spring, having one end operatively connected to and turned by movement of said shaft and the other end connected to said third cam; a notched recess in each of said three cams; means effecting alinement of said three notched recesses when the indicating mechanism is moved to initial, or zero, position; switch operating means connected in controlling relation to said electric switch; a cam block operated by said switch operating means for engagement in said three notches when alined; whereby said switch operating means may be moved to switch closing position only when said cam block is in engagement with said three alined cam notches; and means effecting movement of said cams into non-alining cam notch position upon movement of said switch operating means from switch closing to switch opening position.

DAVID S. WILLSON.