US2660895A

US2660895A - Indexing mechanism

Info

Publication number: US2660895A
Application number: US248503A
Authority: US
Inventors: Daniel V Waters
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1951-09-27
Filing date: 1951-09-27
Publication date: 1953-12-01
Anticipated expiration: 1970-12-01

Description

Dec. 1, 1953 D. V' WATERS 2,660,895

INDEXING MECHANISM Filed Sept. 27, 1951 '2 Sheets-Sheet l D bf WATERS Dec. 1, 1953 D. v. WATERS INDEXING MECHANISM 2 Sheets-Sheet 2 Filed Sept. 27, 1951 //Vl E/VTOP D. M MITERS Patented Dec. 1, 1953 INDEXING MECHANISM Daniel V. Waters, Lebanon, N. J.,

Western Electric Company,

assignor to Incorporated, New

York, N. Y., a corporation of New York Application September 27, 1951, Serial No. 248,503

1 Claim.

This invention relates to indexing mechanism and more particularly to mechanism for indexing a unit pre-determined distances intermittently for locating the unit at given successive positions and locking it against movement during rest intervals.

Many types of indexing mechanisms have been employed to intermittently move or rotate a unit pre-determined distances but due to the ever existing lost motions resulting from the inaccuracies of the manufacture of the parts of such mechanisms, together with variations in their movements due to wear, there is little assurance that such mechanisms will move their units exactly the required distances and hold them against displacement during the intermediate rest intervals.

It is the object of the present invention to provide an indexing mechanism which is simple in structure, readily actuable and highly efficient and accurate over a long period of service.

With this and other objects in view, the invention comprises an indexing mechanism for a unit mounted for rotation about an axis including a member mounted concentric with the axis with spaced notches in its periphery and connected to the unit for rotary movement therewith. A latch, normally actuable to secure the member against movement and to accurately locate the unit in known positions, is released by a cam which functions to actuate a pawl subse quent to the releasing of the latch to move the member with the unit a given distance.

In the present embodiment of the invention, the latch is provided with a cam roller positioned to ride on the outer surface of the cam to release the latch from its member and adapted to be located in a groove of the cam to permit return movement of the cam while the latch remains in its holding position. A door, normally closing the exit end of the groove, may be opened by the cam roller during the return movement of the cam to allow the roller to leave the groove. When closed the door will complete the outer cam surface over which the roller rides during actuation of the cam to release the latch.

Other objects and advantages will be apparent from the following detailed description when considered in conjunction with the accompanying drawings wherein:

Fig. 1 is a front elevational view of the mechanism;

Fig. 2 is a fragmentary isometric view of the latch and actuating cam; and

Fig. 3 is a fragmentary front elevational View of the mechanism illustrating the return movement of the cam and pawl.

Referring now to the drawings, let it be understood that in the present embodiment of the invention, the indexing mechanism is to move a unit It) pre-determined distances about its axis.

The unit It is mounted on a shaft 1 I which is journalled in any suitable bearings not shown. A member l2 fixedly mounted on the shaft 1 I has equally spaced notches M in its periphery providing shoulders I5 for engagement with a pawl 16. The pawl I 6 is pivotally supported at I! on an arm l8 which is mounted for free movement on the shaft l'l between stops l9 and 20. A suitable spring 2| normally urges the pawl I6 counterclockwise so that it will ride on the periphery of the member l2 and enter the successive notches Id.

The member I2 has a circular arrangement of arcuate members 23 spaced from each other so that their tapered ends 24 provide recesses 25 to receive a wedge shaped portion 26 of a latch 21. The latch 21 is mounted for movement on a fixed support 29 and normally urged clockwise by a spring 36. A cam roller 32 rotatably mounted on the opposite side of the latch 21 from the portion 28 is positioned to ride on

surfaces

33 and 34 of a cam 35. The cam 35 is freely mounted on the shaft l l and is provided with an arm 36 which is pivotally connected at 37 to a yoke 38. The yoke 38 is mounted on the upper end of a piston rod 39 of an air cylinder 40 which is mounted on a fixed position pivot 4|. In the present embodiment of the invention, projection 42 of the yoke 38 is positioned to engage and actuate a microswitch 33 mounted at a fixed position and adapted to control a solenoid valve to bring about reverse movement of the air cylinder and the indexing mechanism.

The cam 35 has radially extending surfaces 45 positioned within a yoke portion t6 of the lever l8 with suitable space 51 for lost motion to permit movement of the cam 35 a given distance sufficient to release the latch 21 prior to movement of the lever It a distance sufficient to cause its pawl to move the member l2.

The cam 35 has a groove formed in one side thereof for the cam roller 32 to enter as the cam completes its movement in a counter-clockwise direction. A door 5| of the contour shown is pivotally supported at 52 and adapted to close the exit end of the groove 50. The lower edge of the door 5| is tapered at 53 to conform to the adjacent surface of the groove and its outer surfaces lie in planes with the adjacent outer surfaces of 3 the cam to complete these surfaces over which the roller 32 rides.

Considering now the operation of the indexing mechanism, let it be assumed that at desired intervals of time, a solenoid valve is operated in one direction to cause air under pressure to be directed to the top of the air cylinder 4B to movfe th'eipiston rod 39 downwardly. The first portion of this movement causes the cam 35 to rock about the shaft H to engage the cam roller 32 to move the latch 27 about its pivot 29 moving the wedge shaped portion 2 ;f r ee of the adjacent notch 25. This occurs prior to the engagement of the pawl l'fi' with the adjacent shoulder 15. a I of the yoke 46 and that existing between the end of the pawl H5 and theiadjacentrzshoulder l5, allows suflicient time for the cam to release the latch. Continued movement of the ram "59 downwardly will cause the cam 35 to move the lever I 8 counter-clockwise causing the pawl Hi to move the member-i2 a given distance'determjne'd'by the stopZQ. 'Duringthe c'ounter clockwise travelof thecam 3 5; the latch-21 is moved outwardly while the roller is traveling over the surfaceffifiand the'closedidoor- 5i. The latcrris heldfoutwardly Whileriding'over the cam surface 34,.but wh n thissurface travels beyond the rolleri32, the latch willbe free to move inwardly softhat the 1pr0jection2 6 mayride on the outer surface of the adjacent arcuate member 23' and enter the next notch'25 when brought intoposition. "The tapered ends of the arcuate members 23s and the corresponding'tapered walls of the wedge-like member 25 assureaccurate positioning'of the member 12 with the, unit It and'locking of 'the'member anc'unit against movement during the rest interval of the indexing mechanism.'

'gfThe completion of the'first half of the operatingcycle of the mechanismduring downward moveme t of the ram completes the indexingfof t'e, unit It and the actuation of the switch 43flto operate the solenoid valve, to direct air under-pressure to the. bottom or the air cylinderffi ll to move'the ram 39 upwardly. 'This'actio'n of .the ram rotates the cam clockwise and .tmsmovenrem; the latch?! is in its holdingjfpo sitionwith the groove 56 providing a' bypass for the roller tk2, leaving the latch undisturf-bed. Ihe door 5] would normally close of itsdw wiglflt butjnaybe provided witha spring or other suitable means if so desired to nor- "through operation of imechanism are not complicated in structure and a The 10st motion portion}?! j not 'require delicate machining, these elements in e'accuratejmovement of a unit known measd distances "and the locating and locking of v the V-Vunit .iattheserchosen positions during each operating cycle of the mechanism.

Iti'stobe understoodthat the above described arrangements are simply illustrative of the application of the principles of the invention. iNumerc'u's other "arrangements may be readily :devised bythose skilled in the art which will embody the principles or" the invention and fall within -the spirit and scope thereof.

What is claimed is:

An indexing mechanismfor a unit mounted-for rotationabout an axis, the mechanism comprisinga member mounted concentric with the axis with spaced notchegih its peripheries and connected'to the unit forrotary movement therewith, a latch; normally a-ctuable to engage themember to secure it against "movement, having a proj ection thereon; anoscillating cam h-aving an-outer surface to engage thep'rojection and disengage the latch fromthe member, a groove having a-n o'utlet to serve as a by-pass for the projection-during the-' return movement ofthe cam and a door f or the outlet providing -a part of the outer surface for the' cam, normally-closed and actuable into open position by the projection, and-a pawl niow able by the cam toenter an adjacent notch-inthe periphery of the member to move the members-ubsequent to the releasing of the latch.

DANIEL'v. WATERS.

,Beferences Citedvin the file of this patent UNITED :sTATEs PATENTS Numb Nam Da 7 J35 Q,I5i2 Leman a Qct. 5-,18 86 420,836 Sheridan Feet, 3390 639,892 Fay Dec. 26, 1899