US2298215A - Periodic motion mechanism - Google Patents

Description

Oct. 6, 1942;

c. c. KINKER PERIODIC MOTION MECHANISM Filed Aug. 2, 1940 4 Sheets-Sheet l INVENTOR f @M- 4, a, wwxm OCt. 6, c c KINKER PERIODIC MOTION MECHANISM Filed Aug. 2, 1940 4 Sheets-Sheet 2 INVENTOR 0% 1942- c. c. KINKER PERIODIC MOTION MECHANISM Filed Aug. 2, 1940 4 Sheets-Sheet 4 INVENTOR g VIII/ Patented Oct. 6, 1942 UNITED STATES PATENT OFFICE 2,298,215 PERIODIC MOTION MECHANISM Clarence C. Kinker, Montreal, Quebec, Canada Application August 2, 1940, Serial No. 349,626

8 Claims. (01. 7444) This invention relates broadly to machines such as glassware-forming machines and particularly to the operating mechanisms of such machines. I

Glassware-forming machines exemplify one type of apparatus in which it is desirable to produce periodic motion and at the same time control the motion throughout the entire period of movement. 7

In glassware-forming apparatus, such as is ordinarily termed glass-forming machinery, it is 10 well established procedure to advance the moldcarrying table or tables by periodic movements of equal length and of equal time duration so that each mold of the table is moved from station to station and is brought to rest at each station.

that the movement of the table actuatesat least some of the operating mechanisms carried by it. For this reason, it is highly desirable to control the periodic movements of the table so that it is both accelerated from a stop to maximum speed and decelerated from maximum speed to a stop without appreciable shock to the various rnechanisms involved. It will, of course, .be understood that power will be saved and the efiective life of the operating, as well as the operated, mechanisms will be increased if the periodic movement can be accomplished without appreciable shock.

One of the objects of the present invention is,

therefore, to produce a driving mechanism for an element such as the mold-carrying table of a forming machine, which will'eifectively and efiiciently impart periodic movement to the -element without subjecting the various moving parts to undue wear and tear.

A further object is to produce an operating 40 mechanism for imparting periodic motion to a driven element, which occasions an effective utilization of-the power employed, and maintains substantially efiective control of the driven element throughout the entire cycle of its operation.

A further object is to produce a driven mecha nism for the mold-carrying table of a glassforming machine which imparts periodic movement to such table under conditions such as to substantially continuously control the same and to prevent back lash of the moving parts involved.

A further object is to produce a driving mechanism for a periodic moving device, such as the mold-carrying table of a glassware-forming machine, which is such as to produce periodic movement similar to that produced by a Geneva drive but which minimizes wear on the moving parts.

A further object is to produce a driving mech-- anism which approximates the results accomplished by a so-called Geneva drive, but is such that the imparted movement may be substantially controlled, as to the degree of acceleration or deceleration, throughout all parts of the movement cycle.

These and other objects, which will be made apparent throughout the further description of my invention, are accomplished by means of apparatus illustrated in the drawings, in which Figure 1 is a iragmental and more or less diagrammatic view of a two-table glass-forming .machine in which each table is provided with a are carried by and employed to impart motion to' a driven element such as one of the tables illustrated in Figure 1.

Figures 4 to 9, inclusive, showsuccessive positions of the part of the driving mechanism illustrated in Figure 3 and with Figure 3 illustrate a complete operating cycle of that mechanism.

Figure 10 is a fragmental view diagrammatically illustrating a different form of .driving mechanism and also diagrammatically illustrating an arrangement of tables wherein two tables, such as the tables of Figure 1, are geared together and both are driven by a single driving mechanism.

Figures 11 to 17, inclusive, illustrate successive positions of the portion of the driving mechanism illustrated in Figure 10 and with Figure 10 illustrate a complete cycle of that mechanism.

Figure 18 is a fragmental sectional view along the line A--A of Figure 13; and

Figure 19 is a fragmental plan view of apparatus such as is shown in Figure 18, but in which more structural details are illustrated.

In Figures 1 and 2, I havediagrammatically illustrated two rotatable tables, such as the moldcarrying tables of a glass article-forming machine, and I have diagrammatically illustrated in association with each such table a separate driving mechanism embodying my invention.

2 Each driving mechanism consists essentially of a composite cam mounted for rotation on a standard 20 which is supported in a suitable pedestal and is driven, i. e., rotated, by means of a worm 2| and a worm wheel, not shown but carried by and rigidly secured to the standard 20.

As shown in Figure 2, the worm 2| is mounted on a shaft 22 which is driven by a motor 23 and is provided with an automatic, safety, clutch mechanism 24 for connecting it to and disconnecting it from the source of power when an over-load is encountered. I have illustrated an extension shaft 22 for the driving mechanism of one of the tables and have shown it as coupled to the shaft 22. The extension shaft carries a worm 2lwhich drives the associated device through a worm wheel (not shown).

The composite cam which constitutes an important part of each driving mechanism illustrated in Figures 1 and 2, consists of a heartshaped cam 25 which forms a support for a cam 26 and also a cam 21. As illustrated, the cam 26 approximates the shape of a conventional shield or of a distorted crescent. The cam 21 is offset from the cam 25 and the cam faces 21a and 21b are approximately parallel with'the adjacent face of the cam 25 and, as will be pointed out hereinafter, cooperates with that cam in imparting movement to cam rollers.

Each composite cam imparts periodic movement to a rotatably mounted table 28 and this is accomplished by two series of cam rollers carried by the table. As illustrated, the cam rollers of the A series are rotatably mounted on depending lugs or brackets 29 carried by or formed on the table 28. This series is arranged to contact with the lowermost cams, viz., the earns 25 and 21, and they are positioned for this purpose. The cam rollers of the B series are also mounted on depending lugs or brackets formed on or carried by each table 26, but these lugs or brackets are such that the cam rollers carried thereby clear the cams 25 and 21 and are only capable of engaging the cam 26. As shown in Figures 1 and 2, each cam roller of the B series is associated with one of a cam roller of the A series and the association is such that the axes of the two rollers define a radius of. the associated table 28, i. e., define a line which extends from the center of rotation C of the table 28.

For illustrative purposes, each table 28 is shown mounted on a column 30 in such a way that the column forms a combination pedestal and a mounting column for the table. The rotation of the table is around the axis of the pedestal or column 30. The structural details of the table and of its mounting mechanism play no part in the present invention, except insofar as the table is a rotatable table. For this reason I have not endeavored to disclose full structural details of either table.

In Figure 3 I have indicated by arrow that the composite cam rotates in a clockwise direction around its center of rotation X. The arrows there employed in connection with lines radiating from the table center C also disclose that the table is rotated in a clockwise direction by the associated composite cam. Figure 3 is shown in association with a circle struck from the center of rotation X of the composite cam and subdivided into arcs for the purpose of co-relating the separate cam positions illustrated in Figures 3 to 9 with the illustration of Figure 3.

The positions of the cams shown in Figure 1 correspond substantially to the position of the cam shown in Figure 3, with relation to the cam rollers of the table 28 there illustrated. I refer particularly to the composite cams 25, 26, 21 of the left-hand portion of Figure 1 because I have there designated the associated cam rollers as A, A' and A, B, B and B for the purpose of illustrating the relationship between the cam rollers and the composite cam as the table is advanced in its periodic movement, by the rotation of the cam.

In Figure 1, and consequently in Figure 3 of the drawings, I have illustrated a relationship between the composite cam and the associated cam rollers A, B, A and B which exists at the end of a period during which the table is locked or held stationary by the cooperative action of the composite cam and the cam rollers. This view (Figure 3) fully illustrates the complete fulfillment of one object of the invention in that it discloses the cam rollers A and A in engagement with opposed lobes of the cam 25, and the cam rollers B and B in engagement with the opposed lobes of the cam 26 and under conditions such that the table is under the joint control of both cams 25 and 26 and the four designated cam rollers. .It will be apparent that a relationship of cams and rollers, as here illustrated, positively prevents the driven element from over-running the driving element and, consequently, positively prevents back-lash on the part of the driven element, viz., the table 28.

For convenience of description, I here note that the composite cam 25, 26, 21 is adapted to be continuously rotated at a uniform angular velocity; that during this rotation the associated driven element, i. e., the mold-carrying table 28, is alternately advanced and locked in a stationary position by the cooperative action of the composite cam and the cam rollers and that the periodic locking of the table in fixed positions results from the fact that opposed portions of the faces of both cams 25 and 26 are so constructed that they follow the arcs of circles struck from the center of rotation X of the composite cam and consequently impart neither an impelling nor a retarding force to the cam rollers contacting therewith. I refer to these circular portions of the cam faces as "sections of perfect radius" in order to distinguish them from other portions of the cam faces which impart either an'impelling or a retarding force to the contacting cam roller.

In Figures 3-9, inclusive, I have disclosed a dotted line yy which passes through the center of rotation C of the table and also the center of rotation X of the composite cam. I employ this line 3111 as a datum line for indicating the an-' gular advance of the table which is accomplished by themovement of the composite cam to the different positions illustrated by Figures 3 to 9, inclusive. I also employ a dotted line cz on each of the Figures 4 to 9 for the purpose of designating the angular advance of the table and the angle zcy in each such figure designates that advance.

Figure 4 illustrates the relative positions of the composite cam and the table after the cam is turned through the arc G of Figure 3. During this movement of the composite cam, all of the cam rollers A, B, A, B move oflf the perfect radius sections of the cams 25 and 26 and the rollers A and B cooperate in starting the rotation of the table and also in accelerating its speed of rotation after it starts to move.

As indicated in Figure 3, the cam roller B moves oil the crescent-shaped cam 26 almost immediately after the composite cam starts its movement through the arc G. As a result, the cam roller A assumes the entire burden of checking a tendency on the'part of the table to over-run the driving device (composite cam) or, in other words, the function of preventing back-lash is imposed wholly upon the roller A and the portion of the face of the cam 25 with which it contacts. It should here be noted that the cam roller B is so positioned that it only contacts with the crescent-shaped cam 25 and it, therefore, ceases to perform any function in connection with the table 28 until it again contacts that cam.

Figure 4 discloses that the cam roller A is just about to leave the point of the heart-shaped cam 25 and that, therefore, further rotation of the composite cam, for example, as through the are H, and to the position shown in Figure 5, renders the roller A ineifective in controlling the movement of the table, until it again contacts the composite cam.

The lines yy and 2c of Figure 4 disclose that the table is advanced through the angle zcy by the rotation of the composite cam through the arc G and the corresponding lines of Figure 5 disclose the angular advance of zcy by the rotation of the composite cam through the arc G+H of Figure 3. Figure 5 also discloses that during this movement of the cam, the cam roller A has contacted with the cam face 21a of the cam 21 while maintaining its contact with the heart-- shaped cam 25. Under these conditions, it performs the double function of imparting impelling force to the associated table 28 and of also preventing back-lash on the part of the table.

In Figure 5 the cam roller B is about towmove out of contact with the crescent-shaped cam 25, whereas the cam roller B has just moved into contact with the inner cam face of that cam. It will, therefore, be understood that as the composite cam turns through the are I of Figure 3 and moves from the position indicated in Figure 5 to that of Figure 6, the cam rollers A'B will assume the entire function of impelling the table, whereas the cooperative action between the cam roller A and the cam face 21a will prevent back-lash on the part of the driven element, i. e., the table 28. The above statement should be modified to the extent of noting that as the cam roller A enters the indented or socket portion of the heart-shaped cam 25, it rides off the cam face 21a but still performs the function of an impelling roller and a back-lash preventing roller, since it can only move with the cam 25 through the infinitely short are wherein the cam roller B neither imparts movement to nor checks the movement of the table 28.

Figure 7 illustrates the position of the composite cam after it is turned through the arc G+H+I+J. During this movement, the table has been advanced to the angular position disclosed by the angle zcy of Figure 7. As the composite cam moves through the arc J, the

cam roller A cooperates with the heart-shaped cam 25 in impelling the table and the crescentshaped cam 26 cooperates with the roller B in preventing back-lash on the part of the table. It should also be noted that during this movement of the composite cam, the cam face 21b of the cam 21 cooperates with the roller A in preventing back-lash and that a cam roller 13 moves into contact with the outer face of the crescent-shaped cam.

As the composite cam moves through the arc K of Figure 3 or from the position shown in Figure 7 to that shown in Figure 8, the table is advanced to the angular position indicated by the angle zcu of Figure 8. During this movement, the cooperation between the heart-shaped cam 25 and the roller A continues to advance the table 28 and the cam roller B performs the function of preventing back-lash. Figure 8 discloses that the cam roller B has moved out of contact with the inner face of the crescentshaped cam 26 and is moving to a position where it is engaged by the outer face of that cam. The figure also discloses that the cam roller A is Just moving into contact with the tip of the heart-shaped cam 25.

As the composite cam turns from the position shown in Figure 8 to that shown in Figure 9, it moves through the are L of Figure 3. During this movement, the roller A continues to engage an active impelling face of the cam 25 and to impel the table 28. The cam roller B is in contact with an impelling face of the crescentshaped cam 25 and consequently cooperates with the cam A in impelling the table. Back-lash is prevented by the cooperative action of the cam rollers A and B which respectively engage the cams 25 and 2B.

As the composite cam turns to the position illustrated in Figure 9, i. e., through the arcs G+H+I+J+K+L, the table has been advanced through the angle zcy of Figure 9 which is a full 60. That is to say, the table has been advanced from one stop position to the next and consequently further movement of the composite cam, in completing one cycle of its operation, merely contributes to a locking of the driven element (table 28) in a stationary position.

As the composite cam turns from the position illustrated in Figure 9 to that illustrated in Figure 3, i. e., through the arc M of Figure 3, the cam rollers A and A move onto perfect radius sections of the heart-shaped cam 25 and the cam rollers B and B move onto corresponding sections of the crescent-shaped cam 25, with the result that the moving cam forms a lock for the table and holds the table in a definite position until the cam arrives at, and proceeds beyond a position corresponding to that illustrated in Figure 3. In connection with this locking of the table, it should be noted that the composite cam is engaged by four cam rollers throughout its entire locking travel. This insures holding the table definitely in position and independently of such surface defects as may exist at some portion of a cam or cam roller.

The apparatus illustrated is designed to accomplishthe rotation of a six-station table, i. e., a table which is periodically advanced through angles of 60 and moved to an index position at the end of each such advance. In glass-forming machinery, this would be termed a six-mold table. In such machines, the table must be accurately positioned at the end of each such advance movement and for this reason it is notonly desirable, but necessary to prevent back-lash and thus assure that the table comes to a stop at a definite point in its travel. The advancing and stopping of the table at the different stations is termed indexing, because of the accuracy of positioning required, and the mechanism here illustrated and described is of such character that each complete cycle of the driving mechanism,

i. e., of the composite cam, will not only move the table the same angular amount, but will also lock the table in-an accurately established position, thus insuring that all parts of the glass-forming or other devices carried by the table are moved to proper positions with relation to cooperating mechanisms adjacent to but not carried by the table. That is to say, each cycle of the driving mechanism will advance the driven mechanism an amount exactly equal to every other advance movement and will also look the driven mechanism in a definite predetermined position immediately upon arrival at the predetermined position.

Another feature of the present invention is that apparatus embodying it may be so designed as to produce a desired rate of acceleration .and deceleration of the driven mechanism. While it is highly desirable to start and stop a driven element without shock, it is also desirable to accomplish the complete operating cycle of the driven element in as short a time as possible. With this in mind, the importance of producing a predetermined rate of acceleration and deceleration will be apparent. This feature of the invention is accomplished, in the illustrated embodiments, by providing the driving mechanism with two impelling and back-lash-preventing devices.

In the embodiment described and illustrated in Figures 1 to 9, inclusive, one such device may be said to include the heart-shaped cam 25 and the associated cam 21, together with the cam rollers of the series A. The other such device may be said to include the crescent-shaped cam 26 and the cam rollers of the series B which cooperate with it.

A consideration of the driving mechanism heretofore described will disclose that the so-called separate devices operate both jointly and singly as impelling and back-lash-preventing devices. That is to say, the cam 25 and its associated parts sometimes cooperate with the cam 28 and its associated parts, both in impelling the driven element and in preventing back-lash on the part of that element. During a portion of the cycle it (the cam 25) may cooperate with the cam 25, and associated parts, in impelling the driven element; or it may operate independently of all other cams in impelling the driven element; or, for some portion of the angle, it and a cooperating cam roller, may constitute the sole means for preventing back-lash; or it may operate in connection with the cam 26 in preventing back-lash. Thus it is apparent that the driving and backlash preventing functions are shifted back and forth between the two devices although the shift from one device to the other is usually preceded by a period of joint or cooperative operation.

In Figures to 19, inclusive, I have illustrated a further embodiment of my invention wherein the structural details are such as to make it clearly apparent that the driving mechanism is made up of two separate, but at the same time, cooperating devices, each of which is capable of impelling or propelling the driven element and also of preventing back-lash on the part of that element. As illustrated in Figure 10, the modified form of driving mechanism consists essentially of a combined cam assembly and driving pinion. The cam assembly is similar in some respects to the heart-shaped cam 25 and the associated cam part 21 heretofore described and it cooperates with a series of rollers, corresponding to the series of rollers A, in impelling, stopping and positively aces ms locking the driven element in predetermined positions.

For convenience of description, it is noted that each of said cams 25, 24 and 21 may be designated as a motion-controlling means; that the cam rollers A, A and A, et'c.,'may be designated as one series of contact members; and that the cam rollers B, B and B, etc., may be designated as a second series of contact members. It is also noted that the contact members A, A and A. etc., of the first-mentioned series are adapted to engage and cooperate with two of the motioncontrolling cams, viz., the cams 25 and 21, whereas the contact members of the second series (B, B' B, etc.) are only capable of engaging and cooperating with one such motion-controlling means, viz., the cam 25.

In Figure 10, I have shown two table gears 44 and 4| which are geared together so that a single driving mechanism may be employed in driving both of them. A ring gear 42 is shown secured to the spokes of the gear 40 in such relationship that the two gears 40 and 42 are coaxially located. It might be here noted that the driving mechanism illustrated in Figures 10-19, like the driving mechanism previously described, is

arranged to advance the driven element (gear 40) through an arc of 60 and then stop it and lock it in position. That is to say, the table is indexed every 60 of its rotation. For this reason, the cam assembly forming a part of the driving mechanism cooperates with six cam rollers D which are spaced 60 apart circumferentially of the gear 45 and which, for convenience of illustration, are shown mounted on the spokes of that gear in such relationship that they are held in place by the same devices that secure the ring gear 42 to the gear 40.

As clearly shown in Figure 18, the driving mechanism includes a standard 20 which corresponds to the standard 20 of the so-called composite cam. This standard carries a pinion segment 43 which is rigidly secured thereto and is adapted to mesh with and drive the gear ring 42. The center of segment 43 is coincident with the axis of rotation of the standard 200 and, as is clearly disclosed by the drawings, the segment is adapted to rotate with that standard and with the cam assembly constituting a part of the driving mechanism. This cam assembly is secured to the standard but is located below the pinion segment 43. It consists of a combination of two cams 44 and 45 which are illustrated as integrally formed and rigidly securedvto the standard 25a. The cam 44 is substantially heart-shaped and the cam 45 is similar in shape to previously described cam 21 and cooperates with the cam 44 in much the same way that the cam 21 cooperates with the cam 2-5. The two cams are so located that they provide a cam-way 45 capable of receiving a cam roller D and of such dimensions, with relation to the roller, that the two cams cooperate-in controlling the position of the roller and consequently of the driven gear 44.

It will be apparent from the further description that the cams 44 and 45 in some ways correspond in function to the cams 25 and 21 heretofore described and that the gear element 43 is somewhat similar in function to the cam 25 and that each of these elements 41, 44 and 45 may, therefore, be designated as a motion-controlling means. It might also be noted that the cam rollers D, D and D, etc., correspond in structure and function to the first series of contact members heretofore described, in that they enmakes it apparent that the angular advance of gage and'cooperate with both of the motioncontrolling means 44 and 45, whereas such of the individual gear teeth of the gear 42 as intermesh with the teeth of the segmental gear 43 may be designated as the second series of contact members in that they engage and cooperate with but one motion-controlling means, via, the segmental gear 43.

In Figure 10, the driving mechanism isshown in a relationship with the driven element 46 such that movement of the driving mechanism in a counter-clockwise direction will start to move the,

driven element (gear 46) from the I stationary position in which it has been locked by the cooperative relationship of the cam 44 and the cam rollers DI and D2. The driving mechanism and consequently the segment gear 43 and the cams 44 and 45 rotate continuously and at a substantially uniform angular velocity ina counterclockwise direction with the result that, with the parts as shown in Figure 10, .the roller D2 isjust moving into the cam-way 46 formed between opposed active faces of the cams 44 and 45. Under such conditions, the acting face of the cam 44 functions to impel the roller D2, and consequently the driven element (gear 40), in a clockwise direction while the cooperating face of the cam 45 confines the roller D2 in such a way as to prevent back-lash on the part of the driven element.

It might here be noted that the relationship of the parts is such that the driving mechanism rotates through 315 to advance the table gear 40 through an arc of 60 in the operation of indexing the associated table or tables. The remaining 45' of angular travel of the driving mecha nism is employed in looking the table gear 40 in an indexed position after it has been brought to rest.

In Figure 11 I have shown the driving mechanism after it has advanced through 50 of travel beyond the position illustrated in Figure 10. The roller D2 has entered the cam-track 46 and has been moved in a clockwise direction, with relation to the center of rotation of the gear 40. The roller DI has been moved out of contact with the cam 44 and ceases to function as a motion control device until it again moves into contact with that cam. It will also be noted that the first tooth of the pinion segment 43 is about to go into mesh with the gear ring 42 and thus impose a driving function on the gear segment and ring.

The cams 44 and 45, disclosed by the drawings, are so proportioned that their opposed but cooperating faces are adapted to uniformly accelerate the driven gear 40 at the rate of 135-79- 11-13-15-17-19 units per 5 of angular cam travel of the driving mechanism. Thus it is apparent that the cam-way 46 is of such form as to accelerate the driven element from a stop to full speed in 50 of angular motion. In addition, the cooperative relation between the' cams 44 and 45 (cam-way 46) and the contacting cam roller D, is such that the pitch circle of the ring gear 42 is moving at the same peripheral speed as the pitch circle of the pinion segment 43 after the driving mechanism has accelerated the driven gear 40 from a stop to its maximum speed of rotation, i. e., after the driving mechanism has advanced from a position such as illustrated in Figure to a position such as illustrated in Figure 11.

A- reference to the drawings will disclose that the pinion segment 43 is in mesh with the gear the gear 40 is uniform for all positions of the driving mechanism illustrated in those figures, 1. e., during the entire period the pinion segment is in mesh with the gear ring. It will also be apparent that during this period the pinion segment drives or cooperates in driving the driven gear 40.

In Figure 12 the roller D2 is still in engagement with the opposed and active faces of the cam-track 46, thus making it apparent that the functioning of the cam assembly overlaps that of the intermeshing gear elements 42 and 43 in both driving the gear 40 and in preventing backring 42 in Figures 11 to 15, inclusive, and this lash. It will, however, be apparent that there is no necessity for this double functioning of the driving-mechanism during the period that the motion imparted to the driven element is wellestablished' as a uniform motion, consequently the faces of the cam-way 46 may be relieved, as shown by the dotted lines 41-41 of Figure 12, thus imposing the entire function of impelling and preventing back-lash upon the intermeshing gear ring 42 and pinion segment 43.

In Figure 13 I have shown the relative position of the driving mechanism, the gear ring 42 and the cam rollers DI and D2 when the driving mechanism has advanced through 157 /2 of that portion of its cycle during which it imparts movement to the driven gear 40. That is to say, the positions of the parts illustrated in Figurel3 are those assumed when the driving mechanism has advanced half-way through its 60 indexing movement. It will be apparent that in this position of the driving mechanism the pinion segment 43 is assuming the entire function of driving and controlling the positioning of the driven element if, as suggested, the active faces of the cam-way 46 are relieved as illustrated by the dotted lines 41 of Figure 12. I

In Figure 14 I have shown the relative positions of the parts after the driving mechanism has.

turned through 215 of its motion-imparting travel. A cam roller D3 (carried by the driven gear 46) is approaching the driving mechanism and the gear D2, within the cam-track 46, is approaching that portion of the track wherein the active faces of the cams 44 and 45 again cooperate with the gear segment 43 in controlling the movement of the driven element. That is to say, the cam-way 46 cooperates in driving the driven element and also in preventing back-lash.

Figure 15 discloses the relative position of the parts as the last tooth of the pinion segment 43 moves out of mesh with the gear ring 42 and thus imposes the entire function of controlling the movement of the gear 40 on the cooperating cams 44 and 45 and the cam roller D then engaged by those cams. It will also be apparent that during the next 50 of angular travel of the driving mechanism, that mechanism must function to decelerate the driven gear 40 as a preliminary to bringing it to a stop. Comparison of the opposite ends of the cam-way 46 discloses that the deceleration takes place at the same rate as the acceleration.

In Figure 16 I have shown the relative positions of the parts at the end of the decelerating travel of the driving mechanism, 1. e., at the position where the driven'element (table gear 40) is initially brought to rest. It should be noted, in connection with this figure of the drawings, that the cam roller D3 is now contacting with the active face of the cam 44 and that it, therefore, cooperates with the roller D2 in looking the gear 40 in the index position. It will be understood from the former description of the composite cam of Figures 3-9 that both cam rollers D2 and D3 are contacting with and consequently moving along a perfect radius section of the cam 44.

In Figure 17 I have shown the relationship of parts when the driving mechanism has moved through half that portion of its travel during which the driven element is rigidly locked in position by the cooperative relation between the cam 44 and two of the cam-engaging rollers D carried by the driven element. As the driving mechanism continues its rotation in a counterclockwise direction from the position shown in Figure 17 to that shown in Figure 10, the driven element 40 continues to be held against movement and upon reaching the position shown in Figure the driving mechanism has completed a cycle of its operation. During each such cycle, the driving mechanism accelerates the driven element from a stop to a uniform speed, continues the rotation of that element at the uniform speed throughout a substantial arc of its travel and then decelerates the driven element to a stop whereupon it (the driving mechanism) locks the driven element against further motion and continues to function as a lock while rotating throughout the remaining are (45) of its angular travel.

It will also be apparent that during each such cycle the function of propelling the driven element and of preventing back-lash shifts from the cam assembly (cams M and 45) to the gear elements 42 and 43 and then from those elements back to the cam assembly and all while the driving mechanism is rotating at a substantially uniform angular velocity.

By employing a cam assembly as an active portion of the driving mechanism, I accomplish a flexibility of control over the driven mechanism which would be at least difficult to accomplish with any other type of mechanical motion. That is to say, I can predetermine the rate of acceleration to be employed in accelerating the driven element from a stop to maximum velocity and I can also predetermine the rate of deceleration to be employed in bringing the driven element to a stop at each of the stop positions. This is accomplished by properly proportioning the active faces of the cam assembly (cam-way 46). In this way I can also predetermine the relationship between the period during which the driven element is held stationary, the period during which it is accelerated, the period during which it is propelled at a substantially uniform velocity and the period during which it is decelerated to a stop. In addition, all this can be predetermined in terms of angular velocity of the driving mechanism so that the desired relationship of these periods can be maintained during the operation of the apparatus and independently of the speed of rotation of the driving mechanism.

In addition to the above, by employing a cam assembly similar to those illustrated, I am able to positively lock the driven mechanism in the index positions as soon as it arrives at those positions. Then, too, the use of a cam assembly and the associated cam-engaging parts makes it possible to more effectively prevent back-dash on the part of the driven element than with other forms of motion-producing apparatus. For this reason, it is highly desirable to employ a cam assembly for propelling the driven element during the periods of its acceleration and deceleration,

i. e., during those periods when there is a pronounced tendency on the part of the driven element to either lag behind or over-ride the driving mechanism.

In this connection, it may be noted that I prefer a combination of cam assembly and gear drive wherein the cam assembly continues to function even after the gearing (uniform-velocity drive) mechanism has been operating a sufficient time interval to establish the uniform motion of the driven element. That is to say, if the cam assembly is rendered ineffective throughout the period that the gearing mechanism is effective, then I prefer an operative relationship as disclosed and described in connection with Figure 12. It, however, will be understood that the cam 44 may be cut away as disclosed by the dotted lines SI-Bl of Figure 11 and that the active face of thecam 45 can be correspondingly relieved without rendering the combination cam assembly and gearing mechanism ineffective as a driving mechanism for the table gear 40.

Figure 19 is a view corresponding to Figure 10, except that it is on a larger scale, omits the table gear 4| and includes a fragmental view of a transmission mechanism a, similar in function and arrangement to the transmission mechanism 49 of Figure 1. Figure 19 also includes a more or lessdiagrammatic representation of a drive shaft 22a, associated parts, a worm 2Ia driven by the shaft, and a worm gear 50 driven by the worm 2 la. The worm gear 50 is shown in dotted lines in Figure 19 and as an integral part of or carried by the standard 20a.

Figure 18 is a sectional view of the apparatus shown in Figure 10 with the section taken along the line XVIII-XVIII, as shown in Figure 13. That is to say, the section is taken so as to illustrate the relationship of table gear 40, ring gear 42, pinion segment 43, cam assembly 44 and I5 and one of the cam rollers D at a point in the cycle of operation 'where the driven element has been advanced half-way between two index points. As there shown, the mounting lug and bolt employed for the purpose of securing the cam roller D2 in place may also be employed as a part of the means employed in securing the ring gear 42 to the table gear 40.

While I have illustrated but two embodiments of my invention, it will be apparent that various changes, additions and omissions may be made in the apparatus illustrated without departing from the spirit and scope of the invention as defined by the appended claims.

Having thus described my invention, what I claim is:

1. A periodic motion-producing apparatus including a rotatably mounted driving element, a rotatably mounted driven element, means to rotate said driving element at a substantially constant angular velocity, a composite cam assembly and gear assembly actuated by said driving element for alternately imparting motion from said driving element to said driven element, said cam assembly including two separate motion-controlling cams mounted on and movable with said driving element and a. series of contact members mounted on said driven element and spaced circumferentially thereof and so arranged with relation to peripheral faces of said cams that one such face of said cam assembly is engaged by two contact members to hold said driven member against angular motion in either direction and so that two of such surfaces are engaged by one such member while said cam assembly is accelerating and decelerating said driven element, said gear assembly including gear teeth carried on and movable with said driving element and gear teeth carried on and movable with said driven member which periodically move into mesh with said first-mentioned gearteeth.

2. A periodic motion-producing apparatus including a rotatably mounted driving element, a rotatably mounted driven element, means for rotating said driving element at a substantially constant angular velocity, a composite driving mechanism actuated by said driving element for successively holding said driven element stationary,-then accelerating said driven element from rest to its maximum angular velocity, then driving said driven element at a uniform angular velocity and then decelerating said driven element from such maximum uniform angular velocity to rest, comprising gear assembly carried in part by said driving element and in part by said driven element for imparting uniform, rotary motion to said driven element and a cam assembly comprising two motion-controlling cams carried by said driving element and a series of cam contact members mounted on said driven element, spaced circumferentially thereof and so arranged that one such member is simultaneously controlled by two of said cams and then one of said cams is simultaneously engaged by two contact members while said, driving element is rotating at a substantially constant angular velocity and said gear assembly is ineffective in imparting motion to said driven member.

3. A periodic motion-producing apparatus including a rotatably mounted driving element, means for driving said element at a substantially constant angular velocity, a rotatably mounted driven element and a composite driving mechanism actuated by said driving element for successively holding said driven element stationary, accelerating said driven element from rest to a uniform angular velocity, decelerating said driven element from such uniform angular velocity to rest, comprising three cooperating motioncontrolling cams carried by and rotatable with said driving element, two series of cam contact members mounted on said driven element with the members of each series circumferentially spaced with relation to said driven element and so arranged with relation to said cams that the contact members of one series engage but one of said cams, whereas the contact members of the other series engage and cooperate with each of the two remaining cams and in which the relationship between said contact members and such cams is such that the driven element is always controlled by the cooperative effect of opposed cam surfaces.

4. A periodic motion-producing apparatus including a rotatably mounted driving element, means for rotating said element at a substantially constant angular velocity, a rotatably mounted driven element and a composite driving mechanism actuated by said driving element for successively holding said driven element stationary, accelerating said driven element from rest to its maximum angular velocity, and decelerating said driven element from such maximum uniform angular velocity to rest, comprising three separate motion-controlling means carried by and rotating with said driving element, two series of contact members mounted on said driven element with the members of each series spaced circumferentially thereof, and so arranged that the members of one series contact with but one of said motion-controlling means, whereas the members of the other series engage each of the two remaining means, during the acceleration 5. A periodic motion-producing apparatus including a rotatably mounted driving element,

means for rotating said element at a substantially constant rate, a movably mounted driven element and a composite driving assembly actuated by said driving element for successively holding said driven element stationary, then gradually accel erating said driven element from rest to a uniformtvelocity, then driving said driven element at a uniform velocity and then decelerating said driven element from such uniform velocity to rest, comprising a gear assembly carried in part by said driving element and in part by said driven element for driving said driven element at a uniform velocity and a cam assembly comprising two motion controlling cams carried by and movable with said driving element and a series of spaced cam contact members mounted on said driven element and so arranged that two such members simultaneously contact a cam to hold said driven member stationary and one such member is simultaneously engaged by two cams while said driving member is moving said driven member at a varying rate of speed.

6. A periodic motion-imparting apparatus including a rotatably mounted driving element, means for rotating said element at a substantially constant angular velocity. a rotatably mounted driven element, a gear assembly and a composite cam assembly for alternately. imparting motion from said driving element to said driven element, said gear assembly comprising intermeshing series of gear teeth, one such series being mount ed on and rotating with said driving element and the other such series being mounted on and rotating with said driven element, said cam assembly comprising a substantially heart-shaped cam mounted on and movable with said driving memher, a substantially wing-shaped cam mounted on and moving with said driving member and forming with said heart-shaped cam a camway, and a series of cam contact members mounted on said driven member and circumferentially spaced with relation thereto and so arranged that two such members contact said heart-shaped cam to hold said driven member stationary during the rotation of such cam and one such member moves through said camway while accelerating and decelerating said driven element.

7. A periodic motion-producing apparatus including a rotatably mounted driving element, a rotatably mounted driven element, mechanisms for rotating said driving element at substantially constant angular velocity, a composite driving mechanism actuated by said driving element for successively holding said driven element stationary, then accelerating it from rest at its maximum angular velocity, then driving it unii'ormly at such maximum angular velocity and then decelerating it from such maximum angular velocity to rest, comprising motion-imparting means carried in part by said driving element and in part by said driven element for imparting a uniform angular velocity to said driven element and a cam assembly comprising two motion-controlling cams mounted on and movable with said driving element and a series of cam contact members mounted on and movable with said driven element, spaced circumferentially thereof and so arranged that each such member is periodically simultaneously controlled by both said cams and then one of said cams is periodically simultaneously engaged by two of said contact members while said driving element is rotating at a substantially constant angular velocity and said motion-imparting means is ineflective in driving said driven element.

8. A periodic motion-producing apparatus including a rotatably mounted driving element, mechanisms for rotating said element at a substantially constant velocity, a rotatably mounted driven element and a composite driving mechanism actuated by said driving element for successively holding said driven element stationary,

accelerating it from rest to its maximum angular velocity, and decelerating it from such maximum angular velocity to rest, comprising motion-imparting means carried in part by said driving element and in part by said driven element for p..- riodically driving said driven element, and two separate motion-controlling cams mounted on and rotating with said driving element and a series 01' contact members mounted on said driven element spaced circumferentially thereof and so arranged that each such member is periodically controlled by both said cams and then one of said cams is simultaneously engaged by two such members while said driving element is rotating at substantially constant angular velocity and said motion-imparting means is ineflective in driving said driven element.

CLARENCE C. KINKER.

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