US2273173A - Motion-transmitting mechanism - Google Patents

Description

Feb. 17, 1942. B. BRASSELL 2,273,173

MOTION-TRANSMITTING MECHANISM Filed March 11, 1941 3 Sheets-Sheet 1 mill-51a 420 I 3 flryan firassali Feb. 17, 1942. B. BRASSELL MOTION-TRANSMITTING MECHANISM Filed March 11, 1941 3 Sheets-Sheet 2 ool Feb. 17, 1942. B. BRASSELL 2,273,113

MOTION- TRANSMITTING MECHANISM Filed March 11, 1941 3 Sheets-Sheet 3 I M F 8 aw I 3 ,9, m s as i W 16 a v fi I I I v II l Hill] m M 17 Z 0 If H n m/ Patented Feb. 17, 1942 UNITED STATES PATENT OFFICE 18 Claims.

This invention relates to improvements in motion-transmitting mechanism, and relates more particularly to mechanism involving the driving of a reciprocating driven member and more specifically where such driven member is being driven by a reciprocating drive member.

In mechanical motion which includes a reciprocating drive member, one of the problems is that presented through the condition which is present Within the end zones of the reciprocating stroke. At such time the member is moving in one direction, must come to a stop, and then begin its stroke in the opposite direction; the two strokes are thus separated by an instant in which the inertia of motion of the first stroke must be overcome and brought to its end to form a momentary inertia of rest, and then a new inertia of motion characteristic exerted in the opposite direction, must be developed. At very slow speeds the conditions are less difiicult, but as the speed increases, the difiiculties are largely accentuated through the fact that the speed of approach is greater but must come to its end at the same instant at all speeds of approach; and, after coming to the stop, the stroke in the opposite direction must rapidly develop the running speed, by overcoming the inertia of rest and developing the inertia of motion exerted in the opposite direction. The sudden transitions required will tend to set up conditions of a hammer blow or knock, and thus affect the smooth running of the mechanism.

A favorite method of meeting the conditions is by arranging the mechanism so that the reciprocating member is driven by or drives a member rotating in a circular path--as, for instance, the crank of a crank shaft, as illustrated, for instance, in the steam engine or the internal combustion engine, where the piston is connected with the crank by a crank, one end of which reciprocates and the other is movable through a circular path; the latter end limits the stroke of the piston, and at the same time serves to gradually decrease the speed of approach of the piston to the end of its stroke through the movement of the crank shaft through the zone of its dead center position. A similar effect is set up if the reciprocating member is being driven from a crank-shaft, the circular travel of the latter setting up the speed decrease through the passage of the crank through the dead center zone.

The conditions are complicated in certain types of mechanism, such, for instance, as deep well operations-operations where the driven member is of considerable or great length, although the stroke of reciprocation may itself be comparatively short. For instance, a deep well has its storage basin at considerable depth, requiring the pumping piston to be at the end of a lengthy connection with the power drive member; not only is the Weight of the connection a factor, but, in addition, the weight of the liquid being pumped and located above the piston provides an additional weight factor during the upward movement of the piston. In the downward travel in Which the piston cup is open, the weight of the connection adds its effects to increase the value of the inertia of motion, and thus-aids in producing the hammer-blow effect; on the opposite stroke, the weight of the connection and of the trapped liquid opposes the overcoming of the inertia of rest, and thus tends to put a strain on the structure at such instant. Here, also, the factor of speed adds to the character of the problems since speed of approach increase will tend to increase the hammer-blow effect, and, at the same time, will increase the strain effect at the instant of change, since the piston must pass more rapidly from its position of repose to that of the running speed.

As a result, operations in this particular field are subject to certain conditions which must be met if the activities are to be under smooth running conditions. For instance, if the power be that of a wind-wheel structure, in which the primary motion is circular, the mechanism is arranged to limit the speed so as to provide a sufficient time factor within the dead-center zone such that the speed of approach, stop, and stroke start in the opposite direction can take place without serious hammer-blow or strain efiects. The same is true where a driven pump jack is the prime mover, the oscillations of the latter being the source for the driven member reciprocation. Various forms of mechanism have been employed with a view to increasing the output--as by amplifying the stroke of the piston, etc., but in such cases there has generally been added a shock-absorber device (springs or weights, etc.) since it is inevitable that the increased speed developed also increases the hammer-blow and strain effect referred to, the shockabsorber structure being designed to reduce the effect of these as far as possible.

The present invention is designed to meet the general problem in a somewhat different wayby placing the solution of the problem directly withof the power source an additional action which tends to reduce the hammer-blow effect and the strain of overcoming the inertia of rest, doing this by dividing the pump rod structure into drive and driven elements operatively connected through a unit which itself communicates the drive to the driven member but permits variation in the speed of approach and the power effect in overcoming inertia in such way as to decrease the speed of approach and to decrease the initial speed at the instant of overcoming the inertia of rest, this action being additional to that which may be provided by the dead center zone action referred to above. Since it is apparent that after the inertia of rest has been overcome, the inertia of motion can be accelerated by the use of sufficient power, it becomes apparent that the speed of travel of the pump rod can be increased between the end zones of reciprocation, so that any tendency of delay within the end zones of reciprocation will not lower the speed of operation and pumping effeet-the tendency will be to increase itand at the same time the likelihood of damage to equipment through the hammer-blow and strain effect will be largely decreased. In other words, the normal power speed may be increased without danger, since the possible damaging effects within the end zone of reciprocation have been decreased to an extent such that a considerable speed increase can be provided without bringing these effects beyond the limits heretofore deemed permissible. Hence, the average speed of the assembly is increased over that of the structures heretofore used for the purpose.

The assembly has the additional advantage of having the reciprocating member, which provides the drive member of the assembly, comparatively short and therefore capable of being accurately guided in its linear movements, while the driven member-the pump rod-requires no special guiding structure so that the length of the latter offers no complications with respect to the guiding of its reciprocations, the upper end of the pump rod being operatively connected to the drive member through the unit, while the lower end of the pump rod has the usual piston assemblage structure usually present in such well operations.

The unit comprises a leverage system which, r

in cooperation with controlling guiding faces, has the effect of causing a relative movement between the drive and driven members within the end zone, doing this without disturbing any of the connections, the relative movement decreasing the throw of the driven member as the drive member approaches the end of its stroke, and then building up the normal direct drive speed relationship between the members during travel of the drive member from its rest position for a distance equal to that during which the previous stroke-decreasing action took place, with the restoration movement also caused by such cooperation of the leverage system and the controlling face. In other words, the travel of the drive member remains normal throughout the cycle, but the travel of the driven member, which is uniform with the drive member excepting in such end-zones, becomes varied from the drive member within such end zones, with the variation active to reduce the length of travel of the driven member during the approach to the stroke end of the drive member travel, and then to restore the normal condition during a corresponding length of travel of the drive member at the beginning of the return stroke.

This difference in action within the end zone is not dependent on the rate of advance of the drive member within the zone, but is the result of such advance. Hence, the action is superimposed upon any action in the direction of decrease in speed of advance of the drive member that would be provided by the action of a power crank within the dead center zone. In other words, while movement of the drive member in such end zone to its dead center position shortens the travel distance of such member without affecting the timean action which would be applied to the driven member through the direct connection, the action of the unit, within the same time, is to decrease additionally the length of travel of the driven member, so that the ultimate result is to cause the length of travel of the driven member to be less than that of the drive member within such dead-center zone, with the result that the driven member is brought to its dead center position at a rate slower than that of the drive member in reaching its dead center point, regardless of the time in which such travel takes place, the gradual decrease in rate of advance due to the deadcenter zone effect being carried directly into the action of the driven member.

Hence, at the instant of change in direction of reciprocation, the conditions are most favorable for overcoming the resistance of the load, since the start of the return stroke is under the conditions set up by the previous approach stroke. At such instant the conditions of leverage are made more favorable for overcoming the inertia of rest, and after the load begins to move and to set up the condition of inertia of motion, the unit acts to restore the normal by the travel of the driven member through such decreased distance during travel of the drive member during the remainder of the dead-center zone, so that, as the normal relationship between the members is restored, the drive and driven members will again inove as a unit through the direct drive condiion.

One of the characteristics of the present invention lies in the fact that although the drive member is active at all times as the power source, and the unit at all times acts to operatively connect the drive and driven members, the primary control of the driven member movements passes from the drive member to the unit when the members are in such end zones of reciprocation, returning to the drive member when out of such zone. Because of this the length of such zone is predetermined and is provided by the particular arrangement of the control faces of the unit, the latter determining the value of the variations from the normal set by the drive member reciprocations. In other words, it is possible to control the rate and value of the variations by the particular form of the control faces-after the rate and value have been fixed, they remain constant in action. Hence, in designing the unit, the operating conditions can be considered, and the pattern of the control faces arranged to provide the best efficiency in this respect, the unit then operating under the designed conditions.

While the presence of the seeming yield by the driven member during approach within the end zone of reciprocation may appear to present an analogy to structures of the shock-absorbing type, employing springs, weights, or the like, the unit action is of a different type. Where springs,

etc., are employed to permit the yield, the necessity for direct action outside of the end zones requires that no yield be present excepting within the end zones; hence, the springs must be of suffrcient effective resistance as to avoid yield excepting when the end zone is reached, assuming the springs are active at all times; in such case, the springs must be brought into action by some mechanism, and when brought into action serve to increase the resistance to the movement of the driven member, during approach, and acting as an auxiliary power source at the beginning of the return stroke. If the springs are actual cushions and otherwise separate from the mechanism, serving as a true shock absorber, the same conditions are present, but leave the direct connection as of the type or characteristic of a lost motion device with possibility of derangement. In the present invention, these conditions are avoided, the operative connections remaining constant throughout the cycle-the yield is set up by the leverage system itself acting with the control faces, so that the yield is actually a part of the normal operation of the assembly.

To these and other ends, therefore, the nature of which will be made apparent as the invention is particularly described, said invention consists in the improved construction and combinations of parts hereinafter more particularly described, illustrated'in the accompanying drawings, and more particularly pointed out in the appended claims.

In the accompanying drawings, in which similar reference characters indicate similar parts in each of the views Figure l is a diagrammatic view illustrating the basic features of the invention, including these of the unit, the parts being shown in a position where the drive and driven shafts are operating under the conditions of a one-to-one drive relationship.

Figure 2 is a fragmentary diagrammatic View of a portion of Figure 1, the position shown presenting the elements as beginning the action within the end-zone of reciprocation.

Figure 3 is a view similar to Figure 2 with the parts in position at the extreme of reciprocation.

Figure 4 is a face view of the unit assembly with the casing cover omitted, and showing the drive and driven members, with the parts located in the position of Figure 1.

Figures 5 and 6 are detail sectional view taken on lines 5-5 and 6-6, respectively, of Figure 4.

Figure '7 is a vertical longitudinal sectional view taken approximately on line 1! of Figure 4.

Figures 8, 9 and are detail sectional views taken on lines 88, 99, and [0-40, respectively of Figure 4.

The major feature of the present invention is the unit mechanism which connects the drive and driven member and which makes possible th particular action of the invention assembly in service; an understanding of the fundamentals of this mechanism and its action is therefore desirable before presenting the details, and for this purpose the diagrammatic showing of Figures 1, 2 and 3, will first be explained and analyzed. The views present only those parts that are essential for the explanation, the specific structural arrangement used in practice being disclosed in remaining views.

In Figures 1, 2 and 3, A represents the drive memberand B the driven member.

The drive i to ensure such stroke length with each cycle;

any suitable arrangement to provide this result may be employed, a simple illustration being that of a wind-Wheel operating mechanism which converts the rotary motion of the windwheel into the reciprocating motion of the drive member A, the stroke length being determined by the diameter of the circular path of the crank-pin or its equivalent, present in the translating mechanism. In the latter mechanism it is apparent that the crank-pin will pass upper and lower dead-center points, these providing the limits of the stroke length of the drivemember A.

As pointed out above, such rotary motion of the crank-pin serves to vary the speed of reciprocation of the member, the latter being greatest when the crank-pin is in the zone of the horizontal diameter of reciprocation, the speed decreasing as the pin advances toward and into the zone of the vertical diameter, although the speed of crank-pin advance in its path remains constant; the variations set up in this way have the effect of gradually bringing the reciprocating stroke to its end, since the decreasing speed decreases the value of the inertia of motion until such value becomes practically nil at the point Where the crank-pin passes the dead-center point. As the pin advances after passing this point, it begins the stroke of reciprocation in the opposite direction, the length of movement per unit of time increasing as the pin advances.

Hence, the problems involved in such translation of motion from the rotary to the reciprocating motion reach mainly to the end zones of reciprocation, since it is in these zones that the inertia of motion must come to its end to produce a momentary inertia of rest and then to be followed by the starting of the succeeding inertia of motion activity in the opposite direction.

The speed of the crank-pin can have a definite efiect on the action within such end zones, due to the fact that such speed controls the rate of inertia of motion decrease. Where the speed is high the momentum of the reciprocating member becomes of greater value and tends to oppose the decrease in value of the inertia of motion. Hence, unless provision is made therefor, the assembly is generally limited as to the speed of rotation, since the combination of forces in action within such end-zones of reciprocation can set up damaging elTects such as hammer-blow, straining, etc. In some cases, cushioning devices, such as springs, etc., are employed, to absorb the shocks set up within such zones, but these do not eliminate the difficulty, simply serving to reduce the effect of the shocks on the mechanism itself. Generally, therefore, in ordinary assemblages, such'as windwheel structures and the like, the assemblies are arranged to provide a fixed maximum speed of rotation, with the value placed sufilciently low as to reduce the shock characteristic to a minimum. Obviously, with such fixed maximum values, operation of the wind-wheel at lower speeds reduces the pumping value of the ap paratus, and therefore the efficiency.

Various ways of meeting the conditions have been employed, a favorite one being that of providing a connecting mechanism between the drive and driven members designed to increase the length of the stroke of the driven member over that indicated by the diameter of the circular path, but the speed of rotation remains low in order to avoid the conditions of shock; while such structures tend to increase the volume which can be pumped per stroke, the increase in stroke length also increases the danger of shocks; such structures generally employ shock-absorbers and the like.

In the present invention, the problem is met by deliberately increasing the speed of rotationthe fixed maximum-and thereby increase the average speed of reciprocation, assuming that the power source S is of the type indicated, the source being operatively connected to the drive member A, as by a link L, and setting up the characteristics of converting rotary motion into reciprocating motion. With a lengthy pump rod as the member A such speed increase would not be possible, since the weight of the rod would provide an important factor in tending to maintain and increase inertia of motion during the down stroke. With the present invention dividing the pump rod into drive and driven members, it is possible to provide a drive member A of relatively short length, so that the weight of the member is a comparatively small factor with respect to the value of the inertia of motion of the drive member itself. Hence, it is possible to increase the speed of rotation of the power source without setting up damaging conditions within the end-zone of reciprocation of the drive member and especially the zone at the lower end of reciprocation, since this zone is at the end of the down stroke during which weight tends to augment the value of the inertia of motion.

To compensate and to reduce the conditions of shock brought about by the increased speed, the present invention provides a mechanism which is normally active as a direct connection between the drive and driven membersthus applying the same length and time of stroke action to both membersbut which, in the end zones of reciprocation of the members, serves to reduce the distance traveled by the driven member within such zone to a value less than that traveled by the drive member within such zone; since the time is the same for both members, the decrease in distance by the driven member renders the retarding action more effective, reduces the effect of momentum, and enables the inertia of motion to come to rest with minimum shock effect, even though the speed of rotation has been increased.

This result is obtained by interposing between the drive and driven members A and B an interposed system of controlled leverage such as indicated diagrammatically in Figures 1, 2 and 3. This leverage is located laterally and on opposite sides of the two members, the leverage system on one side being a duplicate of that at the opposite side but with changed direction to provide a symmetrical action and to ensure uniformity in motion. Hence, a detailed description of the mechanism on one side will be sufficient.

The numeral I designates a pin on which the upper end of the driven member B is mounted, this pin passing through an elongated slot a formed within the drive member A, this arrangement permitting relative movement between the two members in the direction of reciprocation. Pin I9 is also carried by the inner end of a leg II of a generally T-shaped lever I I the outer end of which carries the angular leg I I b of the lever, leg I I extending at approximate right angles to leg II the two legs being joined midway in the length of leg II Leg II is provided with a pair of rollers I2 and I2 in the end zones of the leg.

Rollers I2 and I 2 are adapted to cooperate with a control face I3 located laterally of the path of reciprocation of the members A and B, and has its central zone I 3 parallel with such path of reciprocation. The opposite end zones I3 and IS of the control face, however, are curved inward toward the path of reciprocation for a desired distancelongitudinally and laterally of the paththese zones I3 and I3"' also including an outer curved face I 3 and I 3 parallel with the face of zones I 3' and I3, respectively. Control face I3 thus provides a track over which the pair of rollers I2 and l2 can travel, such travel over the central zone I3 being parallel with the path of reciprocation, at which time both rollers will contact the face and leg II a will extend at substantial right angles to the path of reciprocation.

The leg II is operatively connected with drive member A by a link [4, the point of connection of the latter with the leg beinginward of the mid-length of the leg. Since pin it is also carried by the inner end of the leg, and forms the support for the driven member B, the weight of the latter (assuming the path of reciprocation to be vertical) will be constantly applied on to the shorter arm of the leg, thus constituting the leg I a to be a lever of the first order, with the link I l serving as the fulcrum. Hence, if the leverage is moved upward by the upward movement of the drive member, until roller I2 passes from the section I3 of the control face on to the curved section I3 it will be apparent that the possible inward movement of the roller will permit the weight of the driven member to rock leg I I on its fulcrum to the extent permitted by the relief set up by the curved fac I3 it will be understood, of course, that as long as the weight of the driven member remains active as a factor on leg II the rocking of the leg will also move the leg i I with the longer arm of the lever, thus moving the roller I2 inward when relief is present; in other words, the arrangement is such that the weight of the driven member will retain roller I2 in contact with the control face in all positions of the travel of the drive member, excepting when the conditions, presently referred to, provide a superior value to the leverage and thus temporarily overcome the weight of the driven member as a factor.

Because of these conditions, the advance of the structure upwardly into the end zone of reciprocation will, due to the curvature of face It permit leg II a to rock progressively and at rates dependent upon the curvature of the face I3 Two positions are shown respectively in Figures 2 and 3, the former indicating an intermediate position, with Figure 3 being assumed to present the position of the parts at the instant when the power source is passing its upper dead-center position. Obviously, as leg I I a rocks, its angularity to the horizontal is changed, a comparison of Figures 2 and 3 with that of Figure 1, indicating the change in leverage angularity set up by the movement of roller 62 from section I3 to section I 3* of the control face. As will be seen.

the rocking action of leg I l also has the effect of shifting roller l2 from contact with the control face during this movement; this is due to the fact that the lever ll rocks on the fulcrum link l4, so that the outer portion of the leverage rocks as a unit. This swinging of roller l2 from contact does not affect the operation since the weight of the driven member is being supported .by the shorter arm of leg H with the latter supported by the drive member through link l4-rol1er I2 thus limits the possible downward movement of pin under the weight of the driven member, due to the contact of roller I? with the face [3 It".

However, the curved face l3 has an effect on .the angularity of leg H since the inward movement of the roller 12 permits the weight of the driving member to seemingly lower the short .arm of the leg and therefore of pin It; the lowering, however, is only relative, since (assuming the movement to be in the direction of upward travel) the link fulcrum I4 is moving upward and carrying with it the lever ll, Hence, the actual result is that the advance of roller it over face l3 in the upward direction as lever H is being raised, also raises the driven member B but with the latter being raised a distance less than that of the drive member per unit of time, thus providing a differential in the rate of upward advance as between the drive and driven members, the rate of the driven member being less than that of the drive member, with the value of the differential increasing as the point of contact of roller 12 with face [3 moves inward relative to the plane of face lt the differential reaching its maximum at the instant when the drive member reaches its upper dead-center position.

The effect of this action is to superpose upon the normal end-zone conditions of the drive member, a driven member control in which the timing is unchanged, but in which the distance "traversed per unit of time is being curtailed as compared with the drive member, so that the momentum damping effect on the drive member set up by the dead-center zone of the rotating power source, is being materially increased with respect to the driven member, the latter moving upward under the control of the leverage unit but by the power and speed of the drive member, with the length and rate of movement of the driven member less than that of the drive member. It is apparent, therefore, that the speed of the drive member can be increased materially without raising the approach rate of the driven member above that which would be considered safe in structures not employing the unit. In other words, the damping effect that is present 'in the drive member is being augmented by the control action of the unit on the driven member, the unit taking over the control of the endzone of reciprocation of the driven member the instant roller l2 begins to traverse the control face ltb, and providing its individual damping action on the driven member to supplement that which is present in the drive member, the damping action of the drive member serving to control the development of the augmenting damping action on the driven member.

With both members in the upper dead-center positionFigure 3the upward inertia of motion ends, with the succeeding momentary inertia of rest followed by the beginning of the succeeding inertia of motion in the opposite di- ..rection, this taking .place when the crank-pin passes the upper dead-center point and advances angularly in its path of movement. This movement begins the downward movement of the drive member A, the rate of advance being opposite to that provided during the upward movement. The downward movement of the drive member lowers link [4, thus lowering the fulcrum of leg Il and since the weight of the driven member tends to produce a movement of the latter in the same direction, the leverage carrier and the drive member begin the downward travel from the position of Figure 3. However, the movement of the driven member is affected, as during the upward travel. While the link I l is moving downward-thus lowering the leg II and thus the leverage carrier (the lever H and rollers l2 and W), with the weight of the driven member an added factor in tending to move the parts in this direction, the carrier movement can take place only by travel of roller [2 over the face ltb; the carrier movement is a bodily movement, since leg ll cannot rock beyond the point determined by face 13'. Since face l3 is curved, and the downward movement of the roller moves the latter outward, it is apparent that the relative effect of such movement would be to rock leg H in the opposite direction, thus seeming to raise the driven member; actually, the effect is that of lowering the driven member at a rate different from that of link I4; initially, the rate is that of the maximum differential referred to above, with the differential growing less as the roller traverses face I3 until the differential completely disappears the instant roller l2 again reaches face l3 In other words, the development is the reverse of that presented during the upward movement within this zone, the parts passing from the position of Fig. 3, through that of Fig. 2 to the po. sition of Fig. 1. During this travel, the leverage angularity of leg II has been changing until it again reaches the horizontal; during such change the rocking of leg I has rocked the carrier with the result that roller 12 is again brought into contact with face l3 thus having both rollers l2 and [2a active with face l3 At this time (Fig, 1 the carrier is held against rocking since both rollers are active to prevent yield; as a result, the carrier moves bodily with the link l4 and since pin It! is carried by the carrier, the driven member will also move at the same speedthus setting up a one-to-one drive relation between the drive and driven members.

During the movement from the position of Fig. 3 to that of Fig. 1, therefore, there is a development of increasing speed by the driven member to gradually bring the driven member rate of advance up to that of the drive member, this being brought about by the changes in leverage angularly of leg reaches the horizontal.

H until it again During this period the leverage differences provided by the specific lopin H1 and the drive member is made possible by thepresence of slot a in the drive member, the pin occupying an intermediate position in Fig. 1, and moving to "the lower end of the slot in Fig. 3 during the upward travel, returning to the intermediate position when the Fig. l position is resumed.

As the downward travel of the drive member and leverage carrier continues, the carrier begins its approach to the lower end-zone of reciprocation, with the lower roller l2a serving as the advance roller. While Fig. 1 indicates such end zone as the reverse of that shown at the upper end, the activities within the lower zone are slightly different from those described, due to the fact that the weight of the driven member has remained active to retain roller l2 in contact with the control face, and presumably remains active as a power source at all times. Hence, when the downward travel of the carrier causes roller H to reach the point of beginning of action in the zone of face 13' the weight of the driven member would tend to prevent roller 62 from following the curvature of face I3 However, guard face IS is located in position to engage the outer face of roller H and hence, the continued downward movement of the carrier brings roller I2 and the carrierwithin the control face 3 face 13* being shown as curved inward to permit the inward travel of this roller under the action of face 13.

As Will be apparent, when roller [2 begins to traverse face I3, the face moves the roller inward,- thus rocking the carrier. However, the rocking is now in the opposite direction, and therefore in opposition to the weight of the driven member, so that, in effect, face |3--in contrast with face l3 acts as a positive forcing means superior to the weight of the driven member, with the result that the driven member is seemingly forced upward as the roller advances; actually, the effect is to cause the driven member to be lowered at a slower rate than the link l4, thus setting up the development of the differential characteristics that are referred to above in connection with the upper zone. Here, the leverage superiority of the roller end of the lever is of value in overcoming the weight factor of the driven member to increase efficiency.

In other words, the damping effect on the driven member results from two sources which are accumulative in effect. The damping action on the drive member provided by the dead-center zone of the crank-pin travel is communicated directly to leg Il through the link I4, this controlling the rate at which the leverage carrier can lower, and through which the carrier advances roller I2 along face I3. In addition to this, however, the unit superimposes an additional damping action through the effect of the cooperation between roller 12 and face l3 during the roller advance, and which results in rocking leg H and thus the lever |lon its fulcrum, with the shorter end of the leg, with its pin l0, moving upward and thus in a direction opposite that being travelled by the carrier; however, the moving fulcrum passes downward faster than the shorter arm moves upward, so that the combined motion results in lowering the pin in but at a slower rate than the fulcrum. Hence, the downward travel of the driven member is continued, but at a less rate than that of the drive member with the differential increasing as the roller advances, until finally, the end of the down stroke of the drive member brings the fulcrum to the end of its stroke and ends the advance of the roller-with the resultant end of the down stroke of the driven member.

During this development, the rigid and immovable face 13 forces the rocking of the carrier, as indicated, with the result that the outer end of leg H and leg I l move in such manner that roller I2 leaves face l3 and finally reaches a position relative to and distant from such face similar to that indicated in Fig. 3 in connection with roller 12*. In this position the angle of leg II is reversedcompared with the horizontal from that shown in Fig. 3, and pin I2 is located at the upper end of slot l I; this latter results from the fact that the drive member is moving at a greater speed than the pin, and hence the upper end of slot a overtakes the pin. The position is not shown in the drawings, but can be readily visualized by reversing the sheet so that the showing of Fig. 3 will then represent the lower end-zone of reciprocation instead of the upper end-zone. In other words, the action in the two end-zones of reciprocation during the approach to the dead-center positionthe instant of inertia of rest conditionis similar, excepting that in the upper end-zone the effect is produced by the co-action of roller l2 with face I3 while in the lower end-zone the co-action is between roller [2 and face I3, the co-action in both cases resulting in rocking leg I I in a direction opposing that of the movement of the drive member to thereby decrease the rate of advance of the driven member, and necessarily setting up an accumulative damping effect additional to that provided by the damping effect on the drive member, the two control faces W and I3, being active in opposition to the weight factor of the driven member, and with the leverage advantage of the longer arm of leg ll aiding in producing the desired effect.

During downward travel of the driven member-assuming the latter to be a pump rod with its control valve at the lower end-the valve remains open, so that the weight factor at this time is that of the driven member alone. When,

however, the member reaches its lower limit of reciprocation, and the beginning of the succeeding upward stroke is to take place, the conditions change through the fact that the valve closes, thus adding the weight of the trapped content to that of the driven member; it is this combined weight that must be brought into the status of inertia in motion from the momentary status of inertia of rest present in the deadcenter position. Unlike the conditions of the upper zone, this weight factor is in opposition to the power at the beginning of the return stroke, and hence opposes the development of the return stroke instead of aiding it as in the upper end zone.

It is in this condition that the unit presents a positive advantage, through the fact that although the rate of advance of the drive member is initially slow, the rate of initial advance of the driven member is much slower; hence, the problems of overcoming the momentary inertia of rest to begin the succeeding inertia of motion movement are slightly different in the two members, since the ensuing rate of advance of the driven member is less than that of the drive member at the instant of change. In action, the advance of the drive member A-as the power source passes the lower dead-center positionis communicated to leg H through link [4, tending to raise the normal leg fulcrum; since the weight of the driven member is in opposition at this time, raising of the fulcrum would tend to rock the leg due to the presence of the weight; but since leg H cannot rock in this direction without correspondingly moving roller 12* outwardly, the presence of guard face |3' prevents the development of this tendency. Consequently, there is momentarily developed a power condition made up of the contact of roller l2 with face I3'acting as a temporary fulcrumand link I4 as the active power source, with the power being exerted on leg Il the longer arm of the leg being the fulcrum end, and with the shorter arm of the 1eg--with pin I- forming the weight to be moved. As a result, the power value becomes amplified on th driven member in the direction of raising the latter and at the same time the rate of advance of the drive member is materially higher than that of the driven member, thus adding to the power effect, in that the length movement per unitof time is materially reduced as respects the driven member. As a result, the combined forces active at this instant are highly efficient in overcoming the momentary inertia of rest of the driven member to thereby begin the succeeding inertia of motion in the stroke of the opposite direction.

After the inertia of rest has been overcome, the

driven member begins its upward travel, and

since inertia of motion is then present, the unit will then rapidly reduce the differentiation in speed as between the drive and driven members, through the fact that the curved face I3 permits rocking of the carrier in the direction of the horizontal, until the point is reached where roller Ii! again passes on to face l3 at which time the leg Ii is horizontal, and the two members take up travel in unison or in the one-to-one relationship. overcoming inertia of rest, the differentia1 in speed between the two members is at its maximum, with the leverage advantage largely in favor of the power side and active; when inertia of motion develops, the differential in speed or rate is rapidly brought to a zero value to cause the two members to travel in unison until the upper end zone is again approached, thus beginning a repetition of the cycle.

It will be noted that in the above description the developments have been based on the face [3 and guard face l3 as the active faces. Wh'ere the pump is of the single-acting type and the conditions are such that the driven member is constantly active on the unit as a positive and definite weight factor, the two control faces referred tc--together with their counter-parts on the opposite side of the drive and driven memberswould be essential, and a unit having such arrangement (omitting the guards [3 and control faces 13 is deemed to be within the present invention. However, it is possible that operating conditions may arise which could partially or wholly eliminate the weight of the driven member-es, for instance, a, tight-fitting valve formation, or imperfect valve actionin which case the drive member must provide the power for the movement and thereby set up the possibility of disturbing the control relation between these faces and the rollers which co-operate therewith, and to meet this condition, it is preferred that guards [3 and faces 13 be included within the unit, these serving to prevent material departure from the regimen above pointed out, so far as the end zones are concerned, since these will prevent the lever H from being rocked in directions to materially disturb the contact relationship referred to; when both rollers are contacting face w leg ll is horizontal-e condition which remains undisturbed until one of the In other words, at the instant of rollers is permitted to move inward as an endzone is entered. Where, as in double-acting pumps, there is resistance in both the upward and downward directions, the weight of the pump-rod is practically eliminated as a factor, and the structure would then include all of the control faces referred to, the arrangement then practically making the control faces of the two end-zones as substantial duplicates.

The physical structure of the unit may be embodied in several forms one of which is presented in the remaining figures of the drawings as illustrative of the fundamental features of the invention, it being understood, of course, that changes and modifications designed to meet individual conditions would require structural variations and these are considered as coming within the purview of the invention. For instance, it is obvious that the length of face l3 and the length, curvature, etc., of faces [3 and I3 may be varied to meet the conditions of individual installations; also, that the specific formation of the drive and driven members may be varied to meet conditions, the disclosure presenting certain characteristics that should be present; since these can be provided in several forms it is apparent that the disclosure is to be considered as illustrative only.

In the embodiment shown, the unit structure is preferably mounted within a casing 20 of suitabl type and which may be arranged to contain a lubricant-not disclosed-to place the moving parts in a bath of lubricant; the dimensions of the casing will depend upon the installation. If desired, the movable parts may be individually lubricated instead, oil or grease cups being applied as may be found necessary.

The faces l3 l3 and I3 are carried by a member 2|, preferably extending the length of the casing and located at one side of the drive and driven members; a similar member 2 l is located on the opposite side of these members, the two members 2| and 2| presenting the control faces for the two leverage carriers which are also duplicated on opposit sides of the drive and driven members, these carriers having their legs H projecting inwardly and connected with pin 10, the form shown presenting a fabricated structure for simplicity of manufacture and efficiency in operation. The members 2! and Zi have their inner faces cut away to provide a space for the ready movement of parts longitudinally of the casing, while the end zones of the members combine to form a track between which the drive and driven members may move.

The drive member A is shown as of the laminated or skeleton type made up of two plate-like members 22, spaced apart by spacing means, etc., and which include guiding rolls 22 suit-ably positioned to ensure that the member will reciprocate in a constant path. The member is connected to the power source in suitable manner, and extends downward beyond pin It], plates 22 carrying the slot a within which pin It may move during the relative movement of drive and driven members as above explained. The plates 22 may, if desired, extend to the bottom of the casing to enable additional guide roller support, but, as pointed out above, the overall length of the drive member A is short as compared with the length of the driven member B.

The driven member B is preferably fabricated and shown as a pair of plates 30 extending outside the plates 22, with the upper end zone mounted on pin [0 (Fig. 8) and may be guided within the unit by guide rollers; beyond the unit, the driven member may have any desired form.

The levers ll of the leverage carriers, are shown as spaced-apart plates 23 for one carrier and 23 for the other carrier. These plates have the general plan configuration shown in Fig. 4, but, as indicated in Fig. 8, the legs H of plates 23 are bent outwardly, this arrangement being preferred in order to enable the inner ends of legs 8 l to be assembled in simple manner within the zone about pin H]. For instance, Fig. 8 indicates that the inner ends of legs Il of plates 23 lie between plates 22 and 30, while the inner ends of the legs ll of plates 23 lie between spacers 24 and plates 22. Plates 23 and 23 carry the pairs of rollers l2 and 12 one set for each carrier. Suitable spacing members 25 properly position the plates relative to each other. These pairs of plates 23 and 23 and which produce th legs H and ll of Fig. leach carry a pin or bolt 26 which provides the connection with leg I l of link [4; for convenience, the disclosure presents these links as plates which are arranged as a single plate 21 mounted on pin 26 between plates 23--with its opposite end extending between members 22 and carried by a pin or bolt 28, and a pair of plates 2! connecting pin 28 with pin 26 of plates 23 the pair of plates 2'! lying on the outer sides of members 22 and plates 23 as indicated in Fig. 8. Guard faces l3 and E3 are provided as shown.

This general arrangement permits the parts to be fabricated in plate form to produce the composite structures, thus providing strength and lightness to the assemblage. stood, of course, that the fabricated and skeletonized formation disclosed, while preferred, is illustrative, since the specific form and the arrangement can obviously be varied and the parts be formed solid etc.

The unit will be supported in suitable manner to meet the individual operating conditions, the drawings illustrating framing at the ends of the unit, arranged to properly locate the unit relative to the drive and driven members, and to ensure a proper operation of the structure.

The arrangement thus disclosed is more or less illustrative, as heretofore explained, since it is apparent that variations can be utilized to meet different operating conditions, with such variations utilizing the same general principles underlying the invention. For instance, in some cases it may be found desirable to locate links I4 below instead of above pin l0, pin 28 being located below pin Ill instead of above the latter; in such case, the links would provide the same fulcruming action as described, but the push and pull effect of the drive member on the linkage carrier would be reversedthe upward movement of the drive member would serve to push the linkage instead of pullingit as illustrated in the drawings. Such variation could be of advantage in certain types of single acting cylinders, and is obviously a variation which falls within the purview of the present disclosure, and is to be considered as completely within the invention itself. In referring to a 'push action, it will be understood, of course, that although the direction of the movement of the drive member would be upward, thus drawing pin 28 upward, the movement of pin 28 in the upward direction would force the links l4which would then be at the opposite angles from those shown in the drawingsupward and thus push pins 26 upward, instead of drawing them upward as illustrated.

It will be under- While I have herein shown and described the invention as to its characteristics and operation, and have shown a specific embodiment of unit for carrying the same into effect, it is apparent that the fundamentals presented are capable of application in varied ways and that such applications will be subject to the particular environment in which it is made, so that it is obvious that changes and modifications may be found desirable or essential in meeting th conditions of a particular installation, and I therefore desire to be understood as reserving the right to make any and all such changes and modifications therein as may be found desirable or essential in meeting the exigencies of service, insofar as the same may come within the spirit and scope of the invention as expressed in the accompanying claims, when broadly construed.

What is claimed as new is:

1. In motion-transmitting mechanism, a reciprocatory drive member, a power source operative to provide and control the timing and length of reciprocation of such drive member, a reciprocatory driven member in general alinement with the drive member, and a leverage unit operatively connecting the reciprocatory drive and driven members, said unit having a direct drive connection with such drive member to thereby bodily reciprocate the unit in coincidence with the drive member and having direct connection with the driven member to thereby drive the latter, said unit including means operative within the opposite end zones of reciprocation by unit reciprocation for varying the drive relation between the members by varying the leverage angularity of lever elements to thereby control the movement of the driven member within such zones, said driven member movements intermediate such zones being by the unit and in one-toone drive relation with such drive member with the overall length of reciprocation of the driven member less than the similar length of reciprocation of the drive member.

2. Mechanism as in claim 1 characterized in that the means includes a control face means operative to control the leverage angularity of the lever elements throughout the length of reciprocation of the unit.

3. Mechanism as in claim 1 characterized in that the means includes a control face means operative to control the leverage angularity of the lever elements throughout the length of reciprocation of the unit, said control face means having an intermediate portion extending in parallelism with the path of reciprocation of the members and having an end zone curved inwardly to provide end-zone leverage angularity variations of the driven member.

4. Mechanism as in claim 1 characterized in that the means includes a control face means operative to control the leverage angularity of the lever elements throughout the length of reciprocation of the unit, said control face means having an intermediate portion extending in parallelism with the path of reciprocation of said members and having its opposite end zones curved inwardly with like contours to thereby provide and/ or permit end-zone leverage angularity variations of similar characteristics in both endzones of reciprocation of the driven member.

5. Mechanism as in claim 1 characterized in that the means includes a control face means operative to control the leverage angularity of the lever elements throughout the length of reciprocation of the unit, said control face means ineluding an intermediate face portion extending in parallelism with the path of reciprocation of the members, an end zone curved inwardly to provide end-zone leverage angularity variations of the driven member in one of the end zones of reciprocation of such member, and a guard face located at the opposite end of such intermediate face portion, such guard face being curved inwardly and operative to provide end-zone leverage angularity variations of the driven member in the opposite end-zone of reciprocation of such member.

6. Mechanism as in claim 1 characterized in that the means includes a control face means operative to control the leverage angularity of the lever elements throughout the length of reciprocation of the unit, said control face including an intermediate face portion extending in parallelism with the path of reciprocation of the members, an inwardly curved face portion at each end of such intermediate face portion and in continuation therewith, and a guard face spaced opposite to and extending parallel with each curved face, to thereby provide and/or permit end-zone leverage angularity variations of generally similar characteristic in both end-zones of reciprocation of the driven member.

7. Mechanism as in claim 1 characterized in that the means includes a leverage carrier and a control face formation in co-operative relationship, said carrier being operatively connected with the drive member to be driven thereby and also having a direct connection with the driven member, said carrier and the control face formation being co-operative to provide such one-toone drive relationship between the drive and driven members within an intermediate range of travel of the drive member and a differential rate of advance as between said members within the end-zones of reciprocation of such drive member by leverage angularity variations within such end zones.

8. Mechanism as in claim 1 characterized in that the means includes a leverage carrier and a control face formation in co-operative relationship, said carrier having a leverage assemblage and a pair of rollers, the lever assemblage being operatively connected with the drive member and having a direct connection with the driven member, the connection with the drive member being at a point intermediate the connection with the driven member and the rollers, said control face formation being formed with an intermediate portion parallel with the line of reciprocation and inwardly-curved portions at the ends of such intermediate portion, whereby the lever assembly will be retained against rocking by contact of both rollers with the intermediate face to provide the one-to-one drive relationship and will be rocked to vary the leverage angularity when one of the rollers contacts an inwardly-curved face portion to provide the leverage angularity variations.

9. Mechanism as in claim 1 characterized in that the means includes a leverage carrier and a control face formation in co-operative relationship, said carrier having a lever assemblage and a pair of rollers, the lever assemblage being operatively connected with the drive member and having a direct connection with the driven member, the connection with the drive member being at a point intermediate the connection with the driven member and the rollers, said control face formation being formed with an intermediate portion parallel with the line of reciprocation and inwardly-curved portions at the ends of such intermediate portion, whereby the lever assembly will be retained against rocking by contact of both rollers with the intermediate face to provide the one-to-one drive relationship and will be rocked to vary the leverage angularity when one of the rollers contacts an inwardly-curved face portion to provide the leverage angularity variations, the second of the rollers passing out of contact with the control face during such leverage angularity variation.

10. Mechanism as in claim 1 characterized in that the means includes a leverage carrier and a control face formation in co-operative relationship; said carrier having a lever assemblage and a pair of rollers, the lever assemblage being operatively connected with the drive member and having a direct connection with the driven member, said control face formation including an intermediate portion extending parallel with the line of reciprocation, inwardly-curved portions at the end of such intermediate portion, and a guard face for and spaced from each inwardly-curved portion, the guard and curved faces defining a track to receive a roller when moved into the zone of the inwardly-curved portion.

11. Mechanism as .in claim 1 characterized in that the means includes a leverage carrier and a control face formation in co-operative relationship, said carrier having a lever assemblage and a pair of rollers, the lever assemblage being operatively connected with the drive member and having a direct connection with the driven member, said leverage assembly including lever elements of approximately T-shaped configuration, with the rollers carried in the end-zones of the cross-leg of the configuration, with the connection with'the driven member carried in the free end zone of the other leg', and with the connection with the drive member carried by and intermediate the ends of the latter leg to thereby permit rocking of the assembly about the latter connection.

12. Mechanism as in claim 1 characterized in that the means includes a leverage carrier and a control face formation in co-operative relationship, said carrier having a lever assemblage and a pair of rollers, the lever assemblage being operatively connected with the drive member and having a direct connection with the driven member, said leverage assembly including lever elements of approximately T-shaped configuration, with the rollers carried in the end zones of the cross-leg of the configuration, with the connection with the driven member carried in the free end zone of the other leg, and with the connection with the drive member carried by and intermediate the ends of the latter leg to thereby permit rocking of the assembly about the latter connection, the point of connection with the drive member being located to constitute the free end of the latter leg as the shorter arm of the lever.

13. In motion-transmitting mechanism, a reciprocatory drive member, a rotative power source operatively connected to the drive member to convert the source rotary motion into reciprocatory motion of the drive member with the "dead-center zones of travel of the source operative in controlling the timing and length of reciprocation of the drive member, a reciprocatory driven member in general alinement with the drive member, and a leverage unit operatively connected with the reciprocatory drive member to be driven thereby and directly connected with the reciprocatory driven member to drive the latter, said unit being operative to maintain a one-to-one drive relation between the reciprocatory members during rotary travel of the power source intermediate the dead-center zones and operative by leverage angularity variations to vary such drive relation between the members,

when the power source is within such deadcenter zones and with the overall length of reciprocation of the driven member less than the similar length of reciprocation of the drive member to thereby control the end-zone damping of the drive member reciprocations by the power source and to superimpose and augment endzone damping of the driven member reciprocations by unit leverage angularity variations made active by and during dead-center zone activities of the power source.

14. Mechanism as in claim 13 characterized in that the unit includes a leverage assemblage having one of its legs operatively connected to both drive and driven members, said leg extending substantially normal to the path of reciprocation of the members during the one-to-one drive relationship between the members and being angularly varied from such norma1 position during end-zone activities to thereby vary the drive relationship between the members.

l5. Mechanism as in claim 1 characterized in that the drive member overlies the opposite faces of the driven member within the unit zone and is provided with guiding rolls co-operative with unit faces to limit drive member movements to linear reciprocations, said member being slotted to permit relative movement of the drive and driven members in the direction of reciprocation during leverage angularity variations.

16. Mechanism as in claim 1 characterized in that the unit means includes a pair of co-operative leverage carriers and control face formations positioned respectively on opposite sides of the drive and driven members, with the drive member operatively connected with the two carriers individually and with the driven member having a single operative connection with both carriers to thereby cause leverage angularity variations of both carriers to be common in direction and extent.

17. Mechanism as in claim 1 characterized in that the unit means includes a pair of co-operative leverage carriers and control face formations positioned respectively on opposite sides of the drive and driven members, with the drive member operatively connected with the two carriers individually and with the driven member having a single operative connection with both carriers to thereby cause leverage angularity variations of both carriers to be common in direction and extent, each carrier having a skeletonized lever assemblage with a lever leg extending across the path of member reciprocation and with such legs operatively connected with the driven member by a pin connection, each carrier having legs lying outside of opposite faces of the driven member.

18. Mechanism as in claim 1 characterized in that the unit means includes a pair of co-operative leverage carriers and control face formations positioned respectively on opposite sides of the drive and driven members, with the drive member operatively connected with the two carriers individually and with the driven member having a single operative connection with both carriers to thereby cause leverage angularity variations of both carriers to be common in direction and extent, each carrier having a skeletonized lever assemblage with a lever leg extending across the path of member reciprocation and with such legs operatively connected with the driven member by a pin connection, each carrier having legs lying outside of opposite faces of the driven member, the drive member being connected with one carrier by a single link and with the other carrier by a pair of links alined and spaced apart.

BRYAN BRAS SELL.

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