US2953029A

US2953029A - Kinematic control system, chiefly for pumps having an adjustable throughput

Info

Publication number: US2953029A
Application number: US634059A
Authority: US
Inventors: Caillaud Michel Eugene
Original assignee: SEPARATION L EMULSION ET LE ME
Current assignee: FRANCAISE POUR LA SEPARATION L'EMULSION ET LE MELANGE SA; SEPARATION L EMULSION ET LE ME
Priority date: 1956-01-16
Filing date: 1957-01-14
Publication date: 1960-09-20
Anticipated expiration: 1977-09-20

Description

Sept. 20, 1960 M. E. CAILLAUD 2,953,029

KINEMATIC CONTROL SYSTEM, CHIEFLY FOR PUMPS HAVING AN ADJUSTABLE THROUGHPUT Filed Jan. 14, 1957 2 Sheets-Sheet 1 I 2% L; I

FIG. 3

INVENTOR Michel Eugene CAI LLAUD FIG. 2

am M 6 ATTORNEYS Sep 1 M. E. CIAILLAUD 2,953,029

KINEMATIC CONTROL SYSTEM, CHIEFLY FOR PUMPS HAVING AN ADJUSTABLE THROUGHPUT Filed Jan. 14, 1957 2 Sheets-Sheet 2 FIG. 6

INVENTOR Michel Eugene CAILLAUD MI v" ATTORNEYS United States Patent KINEMATIC CONTROL SYSTEM, CHIEFLY FOR PUNIPS HAVING AN ADJUSTABLE THROUGH- PUT Michel Eugene Caillaud, Snresnes, France, assignor to Societe Anonyme Francaise pour la Separation lEmulsion et le Melange (Procds S.E.M.), Paris, France, a French body corporate Filed Jan. 14, 1957, Ser. No. 634,059

Claims priority, application France Jan. 16, 1956 4 Claims. (CI. 74-40) The present invention has for its object a kinematic control system applicable chiefly to measuring pumps of which it is desired to adjust the throughput without modifying the speed of the driving power unit.

Various types of measuring pumps of this kind have been proposed hitherto, chiefly pumps wherein the piston is controlled by a lever system such that it is possible to adjust the length of stroke of the piston and thereby the throughput of the pump. However in such pumps the modification in stroke length is obtained to either side of a medial position so that the dead or idle space of the pump, which is substantially equal to zero when the throughput is at a maximum, increases gradually between said maximum throughput and the minimum throughput, which forms a serious drawback.

My invention has for its object to cut out this drawback and to produce a measuring pump the piston of which is controlled by a lever system in a manner such that whatever may be the length of stroke of the piston,

its dead center which corresponds to a minimum volume of the pump body may remain the same, whatever the adjusted length of the stroke may be, so that the dead space consequently retains permanently its minimum value.

The present invention has also for its object to produce an arrangement for controlling the piston, said arrangement producing, when required, a rapid movement of the piston at the beginning of the suction stroke so as to produce if desired an immediate unseating of the valves, which immediate unsealing is particularly advantageous.

These results are obtained in accordance with the invention by controlling the movements of the piston through the agency of a connecting rod pivotally secured to the piston, the movement of the end of the connecting rod further from the piston being along the arc of a circle passing through a stationary point and the radius of which is equal to the length of the connecting rod which for which the other end of the arc of a circle is located on the line joining said stationary point with the pivotal connection between the piston and the connecting rod when at its dead point, so that it is possible to adjust the stroke of the piston within a range between zero and a maximum, the location of the dead point of the piston remaining the same whatever may be the length of its stroke.

The displacement along the arc of a circle of the end of the connecting rod may be obtained in various suitable manners and chiefly by "means of a four-sided pivotal system wherein, as well known in the art, one of a the arc of a circle described around another pivot which is held fast during the movement of the piston; Any point rigid with said pivot will describe consequently an arc of a circle and it is suflicient to select as a pivotal axis for the connecting rod of the piston a point such that the end of this arcuate movement may coincide with the above-mentioned stationary point. It is then suflicient to make the whole four-sided pivoting link system referred to hereinabove rotate so as to obtain the above-mentioned desired adjusting movement.

Furthermore and for obtaining a rapid movement of the piston with a view to unseating the valves, it is sufiicient to provide, according to the invention, a certain play in one of the pivotal connections of the system and to make a suitably shaped cam engage during the movement of the piston the corresponding pivotal connection at the desired moment in a manner such that, when said pivotal connection begins moving, this is performed at the desired speed.

Further objects and features of my invention will appear in the following description, reference being made to the accompanying drawings illustrating by way of example a preferred embodiment of the invention. In said drawings: a

Figs. 1, 2 and 3 are explanatory diagrams illustrating the operation of the improved arrangement.

Fig. 4 is a view from below of an embodiment said improved arrangement. 7 a

Fig. 5 is a vertical cross-section thereof through line VV of Fig. 4. a

Fig. 6 illustrates a detail on a larger scale.

Turning to Fig. l, 1 designates a pump body inside which a piston'2 is slidingly movable, said piston being rigid with a piston rod 3 carried in its turn by a frame 4 of which one side 5 is pivotally secured at 6 to the controlling driven connecting rod 7. The outer end 8 of said connecting rod is constrained under the action of a suitable mechanism to move along the arc of a circle 9 of which one end is shown at said outer end 8 while the other end of said are is constituted by a stationary point 0 which may be positioned in alignment with the axis of the cylinder or in the vicinity of said axis. The are of a circle 9 has a radius equal to the length of the connecting rod 7 between the pivotal axes thereof and when the outer end of the connecting rod enters during its reciprocation the position 0, its other end lies at a point A on the axis of the pump cylinder, the position of which is such that the piston'2 lies in immediate proximity with the bottom of the cylinder on its dead point position preceding the suction stroke..as illustrated at 2A, the dead space having a size selected according to requirements and being preferably as small as possible.

It will be assumed that, through the agency of adjusting means, it is possible to make the arc ofa circle 9 pivot bodily round the point 0 between a position 9' shown in dotted lines for which it has its center at the point A and a position 9" located between said position 9 and an extreme theoretical position 9" for which the end 8 of said arc of a circle would lie at 8" on the line 0A registering in the case illustrated with the axis of the cylinder.

As mentioned hereinabove, it will be assumed also that for a predetermined position given to the are 9, the end 8 of the connecting rod is adapted to move over said are of a circle 9 under the action of a suitable power unit, said end reciprocating between the position 8 corresponding to the outer end of the arc and the stationary point 0.

Thus, it will be readily ascertained that if the arc of a circle is in a position 9, the end 8 of the connecting rod when moving over said are of a circlewill have its inner end remaining stationary in register with the point A, so that the pistons remains stationary at its dead point 2A 5nd eonsequently the pumpwill' not feed. In 'c'ontradisne'tion, if thel'are of a'circle is shifted so: as to' enter the positic'1ri9 drawn in solid lines, the end of theconnecting -j redi will move between'the point 8 at the outer end .of

the arc "and the point 10 so that the piston will move ";between' its dead point position 2A for which the connec'ting rod is at A and a terminal position forming a second dead point shown by a" hatching at 2, said lastmentioned position corresponding to'the position of the connecting rod 7 drawn in solid lines for which the to one of the arcs 9 of Fig. 1.

It 7 is, then sutfieientto make the terminal pivotal point 8 of the driven connecting rod 7 illustrated in Fig. 1 move over said are 19 and this provides the ,desired movement. Furthermore and with a view to ebfaifiihg. the rotation of the arc of a circle 19, so as .to adjust the. lengthof .stroke pf outer endof the connecting rod is actually at said point :8. T e pump will thus be adapted to operate with a "certainthroughput. By modifying the position of the 7 outer end 8' of the connecting rod between the points 8 aud8" it is consequently possible to adjust the stroke 'ofthe piston and thus the throughput of the pump befltween a zero value corresponding to the location'of the arc at 9"and a maximum corresponding to the posi- 'tion 9" assumed by the are. i J

The movement of .the'outer end 8 of the connecting frod maybe obtained for instance as illustrated in Figs. 2 l and 3 whichare two explanatory diagrams of 'a lever 1 isy stem, according to the invention adapted to produce the above described result,said two figures illustrating respec: I tively two elements of the same pivoted link system arranged in two parallel planes at a certain distance from W each other'so as to'make theoperation of the system more clearly understandable. i

In Fig. 2, 10 designates the axis of the driving shaft of the power unit controlling the pump, said power unit being constituted either by an electric motor or by a suitableengine. Said shaft 10 is rigid with a crank 11 to which' is pivotally secured at 12 a driving connecting rod 1 3 the other end 14 of which is pivotally secured to a secondcrank 15 pivoting round a spindle 16 which is stationary for any predetermined pumping conditions, the position ofthe spindle being however adjustably movable over a circle having its center at 10,.wh'ich circle is the locus of the centers of the arcs 9 in Fig. 1. This provides thus a four-sided pivotal link system as defined by f-

piv ot points

10, 12, 14, 16. Two pivotal connections 10 fa'nd 16 are stationary and form the terminal ends of a included as a part ofthe machine. This link, along with

li lks

11, 13 and 15, form the sides of said link sysj te'm. The pivotal connection 12 describes a circle of a smallidiameter round the axis 10. It will bereadily as- "certained that, under such conditions, the pivotal connection 14 reciprocates over an arc of a circle 17 for each i revolution of' the end 12 of the crank 11, i.e. for each revolution' of the driving shaft 10., For sake of clarity of the drawing, the length of the crank 11 and consef quently the diameter of the circle described by the end 12 have been considerably amplified. As a matter of fact, in practice, its diameter is such smaller and the:

will be subjected during the movement of said crank to 1 -a 1 'eciprocatory angular movement and in particular the po1 nt 19 of said link, which is located at 19' inpregistry 'with the-axis 0 when the pivotal connection 14 is at 14",

' will move over the are ofa circle 19 between 'said posiflou -19" coinciding with the axis 0- and a further position -19f over the circle 19 described byflsaid point.

I; ih e u e v the e i f de n t m v ment of a point-on said are of a" circle 19corresponding the piston, asjexplafiiied hereiiiabove,"'it' is sufliie shift the point 16 overthe'arc of a circle 20 between'predetermined limits constituted on the one hand by the point Z0: and on e ptherjhahd' by a point 20'" located in the quadrant 20%2Q'.

closed inside a casing 21 filled with oil andthrough which passes a control shaft 22 the 'axis of which forms materially the pointgO of "the preceding figures. [5x des- "ignates a sliding memberrigidly' connected with the pistonand forming materially che frame 5 of Fig. 1. Said "'shown, forms the pivotal axis 12 of Fig. 2, to which jsliding member 5x is pivotally secured in itstu-rn' at 6x round a spindle forming materially the pivotal connectionl6 of'Fig. l. Io the-shaft 22 is' 'keyed on the other hand an eccentric died 25 the of which, which is not axis is's'ecured a member 13x forming the driving conplay for a purpose 'to be disclosed hereinafter, to a ""spindle l4 x'forming the pivotal connection 14 of Fig.

ZandIcarried in-'its turn by a plate 151: formingfhe crank 15iin one with the link "18of Fig. 2., Said plate is pivotally "secured in'i'its turn throughau eccentric 1 spindle 16x forming the pivotal connecting point 16to 1a member 31"adaptedto pivot with reference to the frame zl coaxially with the'shaft 22." The periphery 'of this member 31 a worm"32 forming arciiate rack engaging a worm 3 3 fitted inside a casing 34' carried by the frame, said worm being controlled from the Q outside through a handwheel35. It will thus be readily ascertained that it is' possible through action on the .Furthermore there is pivotallysecured to thespindle 6x a memberj7x formingl theactual driven connecting rod and surrounding the plate 15:; so that it'maypivot withreference' to the latter roundan axis which is'not illustrated and which corresponds to the -axis 19'of 3} in other words; said pivotal. axis coincides'with'the axis O'for the dead point position illustrated inFigsf. 4

inemberfZS, the'plate '15x""r'ocking roundfthe spindle [16x assumes a reciprocation over the f are of. a circle When the s aajzz rotates, together with' the were.

I" having its, center on 'the spindlelfix, "said reciprdCa ion being imparted thereto by the" spindle 14x connecting it with the eccentiicfmeniberfsaid plate 15:; carries airing with it in its turn the driven coniiecting rod 7;; which produces finally the spindle 16); the reciprocaiq of. h .m be. 52 ri hlt P s As mentioned hereinabove, it may beof advantage in certain cases to give the piston at the beginning of the suction stroke a companatiyely' sudden movement so as to unseat th'e'suetion valve. To this end, the member 13x5 or come ih roa tsyisfined with a clearanceion the spindle 142 through theeg'encyof a g-27 iFig. 6) while on the other 'hand, the shaft 22 carries a cam 38 keyed coaxially to the eccentric member; the major part of the periphery of said cam is circular and coaxial with the eccentric member 25 with the inclusion of a receding section 39. Said cam is adapted to cooperate with the roller bearing 27. As long as the roller bearing is in contact with the circular section of the cam periphery, the member 13x cannot be shifted with reference to the spindle 28; when however at the end of the delivery stroke of the pump, the piston reaches its dead point, it is driven positively-by the eccentric member up to the position illustrated in Fig. 4, but from this moment onwards the receding section 39 of the cam engages the roller bearing 27 so that the latter leaves a slight clearance between it and the member 13x. The eccentric member continuing then its rotation, said spindle 14x and consequently the member 13x have a tendency to remain stationary at first as a consequence of this clearance.

However, after a short time, the cam acts again on the raceway of the roller bearing and gives the latter and consequently the entire mechanism a movement towards the left hand side (Fig. 4) which corresponds to a comparatively sudden movement of the piston which has for its result an unseating of the valves. Consequently, the mechanism continues its rotation so that the circular portion of the cam periphery engages again the raceway of the ball bearing and the member 132: is again driven along without any clearance. It should be remarked furthermore that the movement of the piston which is thus executed during the suction stroke requires only the work which is necessary for overcoming the passive resistances although the active section 39 of the cam operates only with a very reduced stressing.

It is obviously possible to bring various modifications to the arrangement disclosed without unduly widening the scope of the invention defined in the accompanying claims, Without any limitation of the invention to the application referred to.

What I claim is:

l. A variable stroke mechanism for piston pumps, comprising a reciprocating piston rod rigid with the pump piston, guiding means forming a rectilinear path along which said piston rod is shifted between an unvarying end position and an adjustable end position, a rotary driving member adapted to revolve around an axis crossing at right angles the line defined by said rectilinear path beyond the unvarying end position of the piston rod on the latter with reference to its adjustable position, a normally stationary pivot, means for adjustably shifting said pivot into any selected position on an arcuate path surrounding coaxially the rotary axis of said rotary driving member and extending between a point aligned with said rectilinear path between the rotary driving member and the unvarying end position of the piston rod and a point lying on a line passing through the rotary axis of the driving member perpendicularly to the rectilinear path, a link pivotally secured to said normally stationary pivot and controlling the piston rod through a point of said link registering with the axis of the control member when the piston rod is in its unvarying end position, a lever system operatively connecting a further point of said link with the driving member and including a radial crank rigidly secured to the rotary driving member and a driving connecting rod pivotally connecting the outer end of the crank with said further point of the link with a clearance between said link and said driving connecting rod, the crank rotating in unison with the rotary member to constrain said driving connecting rod to make the link rock around the normally stationary pivot and thereby reciprocate the piston rod over said path, a cam rigid with the crank and adapted to shift the driving connecting rod into engagement with the link, and to cut out said clearance for all positions assumed by the driving connecting rod outside one of the dead points of its stroke, the shifting of the normally sta- 6 tionary pivot over its arcuate path adjusting the location of the adjustable end position of the piston rod on its path.

2. A variable stroke mechanism comprising a reciprocating member, guiding means forming a rectilinear path along which said reciprocating member is shifted between an unvarying end position and an adjustable end position, a rotary driving member adapted to revolve around an axis crossing at right angles the line defined by said rectilinear path beyond the unvarying end position of the reciprocating member on the latter with reference to its adjustable position, a normally stationary pivot, means for adjustably shifting said pivot into any selected position on an arcuate path surrounding coaxially the rotary axis of said rotary driving member and extending between a point aligned with said rectilinear path between the rotary control member and the unvarying end position of the reciprocating member and a point lying on a line passing through the rotary axis of the rotary driving member perpendicularly to the rectilinear path, a link pivotally secured to said normally stationary pivot and rotary driving the reciprocating member through a point of said link registering with the axis of the control member when the reciprocating member is in its unvarying end position, a lever system operatively connecting a further point of said link with the rotary driving member and including a radial crank rigidly secured to the rotary driving member and a driving connecting rod pivotally connecting the outer end of the crank with said further point of the link, the crank rotating in unison with the rotary driving member to constrain said driving connecting rod to make the link rock around the normally stationary pivot and thereby reciprocate the reciprocating member over said path, the shifting of the normally stationary pivot over its arcuate path adjusting the location of the adjustable end position of the reciprocating member on its path.

3. A variable stroke mechanism comprising a reciprocating member, guiding means forming a rectilinear path along which said reciprocating member is shifted between an unvarying end position and an adjustable end position, a driven connecting rod, the first end of which is pivotally connected to said reciprocating member, a rotary driving member adapted to revolve around an axis crossing at right angles the line defined by said rectilinear path beyond the unvarying end position of the reciprocating member on the latter with reference to its adjustable position, a normally stationary pivot, means for adjustably shifting said pivot into any selected position on an arcuate path surrounding coaxially the rotary axis of said driving member and extending between a point aligned with said rectilinear path between the rotary driving member and the unvarying end position of the reciprocating member and a point lying on a line passing through the rotary axis of the driving member perpendicularly to the rectilinear path, a link pivotally secured to said normally stationary pivot and controlling the second end of the driven connecting rod of the reciprocating member through a point of said link registering with the axis of the driving member when the reciprocating member is in its unvarying end position, a lever system operatively connecting a further point of said link with the rotary driving member and including a radial crank rigidly secured to the rotary member and a driving connecting rod pivotally connecting the outer end of the crank with said further point of the link, the crank rotating in unison with the rotary member to constrain said driving connecting rod to make the link rock around the normally stationary pivot and thereby reciprocate through said driven connecting rod the reciprocating member over said path, the shifting of the normally stationary pivot over its arcuate path adjusting the location of the adjustable end position of the reciprocating member on its path.

4. A variable stroke'mechanism comprising a reciprocating member, guiding means forming a rectilinear path along which said reciprocating member is shifted f'b 'et weenfan nnvarying e'ndjposition and an adjustable *end p ositionja driven connecting rod, the first end of Whichispivotally connected to said reciprocating member, otary drivingmember adapted to revolve around an trlmear path beyond the unvarying end position of'the iii'eciproeatingj member on the latter with reference toits' V -adjnstable position, a normally stationary pivot, means for' adjustably'jshifting said pivot-into any selected posi- "'t'ion on an arc'nate pathsurrounding coaxially the rotary" Tthioh'gh the rotary axis of the driving member 'perpen-e f'dienlarly to the recilinear 'path, a link'the length of which I s' equal to that of the driven Connecting rod, pivotally onncted "to "said normally stationary pivot and con- ";"trolling' "the second end of the drivenconnecting rod of f the reeip'r'ocating member throngh a point of said link;

"i'egis'tering with'the axis of the driving member when the reciproeating member is in its unvarying end position, a "le'vensysteitn' operatively connecting 'a further point of said link with the c'ontrol'member and including a radial crank V s'crossing at fight angles the line defined'by said ree- E '"rigidlyrsecured to the rotarymeniber and a 'drivingbonnially, stationary 7 pivot and thereby reciprocate through said driven connecting :rod the reeiprocating'member over said'path, the shifting of the normally stationary pivot over its areuatepath adjusting'thelocation Y of the ad- 10 justable-end position of the reciprocating member on its path. 7

' Referenes Cited inthe file 'of this patent I I ITED' STATES" PATENTS 1,112,832 {Pierce oc e ipjn 32181436 Towler Dec. 12, 1939 2,303,597 Adelson Dee 1, 1942 j 2,548,738 Orlich et al. Apr, 10, 19:51 2,587,395 Sheen Feb. 26,11952 21,737,896 Meyer Marl 13f19'56 a FOREIGN PATENTS 291,295 i'svvitz erland ism, 1, 1953 Y855,'890 France' May '22, 1940