US2538193A - Vane track for hydrodynamic machines - Google Patents

Description

Jan. 16, 1951 w. FERRIS 2,538,193

VANE TRACK F OR HYDRODYNAMIC MACHINES 3 Sheets-Sheet 1 Filed April 10, 1944 INVENTOR WALTER FEH'R'IS ATTUHNEY.

Jan. 16, 1951 w. FERRIS VANE TRACK FOR HYDRODYNAMIC MACHINES Filed April 10, 1944 3 Sheets-Sheet 2 INVENTOR B, E N R Fm T R A L W W. FERRIS VANE TRACK FOR HYDRODYNAMIC MACHINES Jan. 16 1951 3 Sheets-Sheet 5 Filed April 10, 1944 INVENTOR T TD H N EY.

Patented Jan. 16, 1951 VANE TRACK FOR HYDRODYNAMIC MACHINES Walter Ferris, Milwaukee, Wis., assignor to The Oflgear Company, Milwaukee, Wis., a corporation of Wisconsin Application April 10, 1944, Serial No. 530,425

This invention relates to hydrodynamic machines of the sliding vane type and more particularly to the vane tracks which guide the vanes of such machines in their inward and outward movements.

The vane track of a hydrodynamic machine includes a plurality of abutments or bridges, with which the vanes coact to provide substantially liquid tight seals between the inlet and the outlet ports of the machine, and a plurality of track sections which are arranged between the bridges and form therewith a continuous track upon which the outer ends of the vanes ride during rotation of the rotor. The bridges are ordinarily arranged in pairs with one bridge of each pair arranged close to the periphery of the rotor and with the other bridge spaced from the periphery of the rotor when the machine is performing useful work, the bridge which is close to the rotor being called the sealing bridge and the bridge which is spaced from the rotor being called the pumping bridge or the working bridge. If all of the bridges are stationary, the displace ment of the machine is constant but the displacement may be varied by providing means to move the working bridge of each pair toward and from the rotor.

Vane type hydrodynamic machines are extensively used as pumps but a properly designed vane type hydrodynamic machine may function as a motor. When the machine is used as a pump, its rotor is ordinarily rotated at such a high speed that the centrifugal force is sufficient to keep the vanes in contact with the track and it is only necessary to hydrostatically balance the vanes. However, if the machine is to be operated at slow speeds, as by being used as a motor, the centrifugal force is insufficient to keep the vanes in contact with the track in which case the machine is provided with suitable means for positively moving the vanes outward such as means for supplying high pressure liquid to the inner ends of the outward moving vanes.

When the working bridges of a machine having two pairs of bridges are spaced from the rotor and the rotor is rotated, each vane will move inward as its outer end moves from a working bridge toward the adjacent sealing bridge, it will move outward as its outer end moves from the second bridge toward the third bridge, it will move inward as its outer end moves from the third bridge toward the fourth bridge and it will move outward as its outer end moves from the fourth bridge toward the first bridge. Each vane thus makes two reciprocations during each revo- 21 Claims. (01. 103-136) lution of the rotor and, since the rotor is often driven at very high speeds, the reciprocations may be very rapid.

If the vane track is so shaped that it forces each vane inward too rapidly, the vane will tend to dig into the track and thus cause excessive wear of the track or the vane or both. If the A track having a surface so shaped as to cause uniform accelerations and decelerations of the vanes would provide an ideal condition which may be approached in a unitary rigid vane track for a constant displacement machine but 'in a variable displacement machine the contour of the track will vary as the movable bridges are moved inward and outward to vary the displacement.

It has heretofore been proposed to provide a hydrodynamic machine with a vane track hav ing flexible track sections arranged between the bridges and to bend the flexible sections as the bridges are moved inward and outward but the flexibility of one section may be different from that of another section and the exact point at which maximum bending takes place is unpredictable so that the accelerations of the vanes cannot be determined with any degree of ac curacy. Also, such vane tracks are difficult to manufacture, especially for use with long rotors, and it would be difficult and expensive to prepare to manufacture such tracks in commercial quantities. I

Various other adjustable vane tracks have been proposed but such tracks require auxiliary supports and/or are of such contour when adjusted to certain lengths that they cause the vanes to accelerate and decelerate at rates outside the desired range.

The present invention has as an object to provide an extensible vane track which is free from the objectionable characteristics set forth above.

Another object is to provide vane track having extensible rigid track sections arranged between the bridges and supported solely by the bridges.

Another object is to provide a vane track hav-' ing a vane guiding or track surface which consists entirely of concave and convex circular arcs. I

Another object is to provide a vane track having a track surface consisting entirely of concave and convex arcs which are tangent at their junctions with each other.

Another object is to provide a vane track in which extensible vane track sections having con-- cave track surfaces are pivotally connected to adjacent bridges and each bridge has a track surface which is concave intermediate .its ends but is convex at its ends to provide convex transition curves between adjacent track surfaces.

Another object is to provide an extensible vane track section having a circular track surface and circular telescoping guide surfaces which are concentric with the track surface.

Another object is to provide a hydrodynamic machine with a vane track which may be adjusted to vary the displacement of the machine and which has a radial port for the flow o'f'liqui'd to and from the rotor of the machine.

Another object is to provide an extensible vane track that .may be readily manufactured.

Other objects and advantages will appear from the description hereinafter given 'of vane tracks in which the invention is embodied. The invention is exemplified by the vane tracks of the "pumps shown somewhat schematically in the accompanying drawings in which the views are as follows:

Fig. 1 is a transverse section through one half of'a pump in which vane tracks constructed according to the invention are incorporated and which shows the pump-adjusted to maximum displacement and including in its vane track the "track section shown in Figs. 3-6.

Fig. 2 is a transverse section through the opposite half of a similar pump and shows the pump adjusted to minimum displacement and including in its vane track the track section shown in Figs. 7-11.

Fig. '3 is a view of the inner. peripheral face of one of the track sections shown in Fig. l and it includes portions of the bridges to which that section is connected.

Fig. 4 is an end or edge view showing the two parts of the track section .shown in Fig. 3 separated .from each other.

Fig. .5 is a view of the outersides of the track section ,parts shown in Fig. 4.

.Fig. 6 is a transverse .section taken on the line 6-6 .of Fig.5.

Fig. 7 .is an end or edge viewof one of the track .sectionsshown in .Fig. 2,, the view including portions of the bridges to which the section is pivoted.

.Fig. 8 is a view of the inner faces of the parts shown in Fig. 7.

Fig. 9 is an end or edgeview showing the two parts of 'the track section shown in Fig. 8 separated from each-other.

Fig. :10 is a view of the outer sides of the track section parts shown in Fig. 9.

Fig. 11 .is'a transverse section taken on the line II-II of Fig. 8. Fig. 12 is .a diagram illustrating a method for determining the lengths of the radii of the track surfaces on the bridges and track sections of a hydrodynamic machine such as the pump shown in Fig. '1.

For the purpose of 'ilustration, the invention has been shown incorporated in variable displacement non-reversible pumps but it may as readily be incorporated in reversible pumps or in motors.

The-pumps shown inFigs. 1 and 2 each have a plurality of vanes I slidable in suitable slots formed radially in a cylindrical rotor 2 which is fixed upon a shaft 3 to be rotated thereby. The outer ends of vanes I engage an endless track upon which the vanes ride when the rotor is rotated. The vane track includes two diametrically opposed sealing bridges 4 and 5, which are fixed in stationary positions close to the periphery of rotor 2, two pumping bridges 6 and I which are spaced from the other two bridges and are adapted to be moved toward and from the periphery of rotor 2 to vary pump displacement, and four extensible track sections each of which is arranged between and connected to adjacent bridges, the track sections shown in Fig. 1 being designated by the reference numeral 8. Bridge 1 has been shown arranged close to rotor 2 to illustrate the position of the parts when pump displacement is zero and bridge 6 has been shown spaced from rotor 2 to illustrate the position of the parts when pump displacement is near maximum.

The rotor and the vane track-are arranged between two cheek plates and within an annular spacer ring all of which is enclosed in a suitable casing. For example, the pump shown in Fig. 1 has its rotor and vane track arranged inside of an annular spacer ring 9 and between two cheek plates (not shown) which engage opposite sides of ring 9, and the entire assembly is enclosed within a casing ID.

The bridges are closely fitted between the cheek plates and in suitable recesses formed in the spacer ring, sealing'bridges 4 and 5 being fixed in stationary positions while pumping bridges 6 and 1 are slidable in their recesses and adapted to be moved inward and outward by any suitable means to vary the displacement of the pump.

The space between the periphery of rotor 2 and the inner periphery of spacer ring 9 communicates with two interconnecteddiametrically opposed intake ports II and two interconnected diametrically opposed discharge ports I2 which are arranged adjacent to the periphery of the rotor, only two of the ports being shown. Each port is arranged between adjacent bridges, and liquid seals between adjacent 'ports are provided by the bridges and the vanes in contact therewith.

Since vane type pumps are well known and since a typical pump of this type is illustrated and described in U. S. Patent No. 2,141,171 to which reference may be had for details of construction and mode of operation, further illustration or description of the pump is thought unnecessary, it being deemed sufficient to state that, when rotor 2 is rotated in the direction of the arrow and the pumping bridges are spaced from the rotor, the vanes will move progressively outward as the outer ends thereof move along the vane track from a sealing bridge to a pumping bridge and they will be forced inward by the track as the outer ends thereof move along the track from a pumping bridge to a sealing bridge.

The spaces between the outer ends of the outward moving vanes will be filled with liquid from intake ports I I and, as each vane crosses a pumping bridge, the liquid between it and the preceding vane will be discharged through a port I2.

If the track surface on each track section were of such a length that one of its ends would abut the end of the track surface on the adjacent sealing bridge when pump displacement was zero and its other end would abut the track surface on the adjacent pumping bridge when pump displacement was maximum, one end or the other of the track surface on the track section would move away from the track surface on the adjacent bridge as the pumping bridge moved in one direction or the other so that there would at all times be a gap in the vane track at one or both ends of each track section.

In order that the track sections may be con nected to the bridges and provide an unbroken path for the vanes, each stationary bridge has portions It at opposite sides thereof reduced in thickness, each movable bridge has portions I! at opposite sides thereof reduced in thickness, each track section 8 has notches or recesses l8 and I9 formed in opposite ends thereof to-receive reduced portions I6 and I1, and the notched end portions of each track section are provided with holes 20 and 2| to receive pins 22 and 23 by means of which each track section is pivotally connected to adjacent bridges, the notched portions of the track section overlapping the reduced portion of the bridges to provide an unbroken track surface as shown in Fig. 3.

Each track section 8 includes two principal parts 26 and 21, which have an arcuate T-shaped groove 28 formed therein and extending through the outer periphery thereof, and an arcuate T-shaped guide segment 29 which is fitted in groove 28. The inner peripheral faces'of parts 26 and 2! are finished to the same radius to provide a smooth track surface for guidingthe vanes and groove 28 is formed concentric with the track surface so that guide segment 29 may hold parts 26 and 21 in alinement with each other while permitting the two parts to move relatively to each other in a circumferential direction to vary the length of the vane track. The arrangement is such that each track section 8 is pivotally supported at its ends and it is self-supporting inter mediate its ends. Segment 29 is preferably fixed to one of the two parts, such as part 21, as by means of a pin 30.

The adjacent ends of parts 26 and 21 are so shaped as to provide an unbroken path for the vanes as they pass from one part to the other. For example, the inner end of part 26 may have two oppositely inclined faces 3| which converge upon the centerline of the track and, the inner end of part 2'! may be provided with oppositely inclined faces 32 which diverge from the centerline of the track so that the end of part 21 is complementary to the adjacent end of part 26 as shown in Fig. 3. This arrangement provides a bearing for nearly the entire width of each vane while it passes from one to the other of the two parts of each section.

The vanes move radially when the pump is discharging liquid and the radial accelerations of the vanes must be maintained within certain limits in order that the outward moving vanes may remain in contact with the track and in order that the vanes being forced inward by the track may not bear so heavily against the track as to cause excessive friction and wear.

If the track surfaces of track sections 8 and bridges 4, 5, 6 and i were concentric] with the rotor, the track would form a perfect circle when the displacement of the pump was zero at which time the vanes would have no radial movement but when the pump was adjusted to maximum displacement, at which time the'radial movement of the vanes would be maximum, the track surface on each track section 8 would form an angle with the track surface on the adjacent bridge. The accelerations of the'vanes riding upon the concave track surfaces may be maintained within the permissible limits but, as each vane passed across the angle at the junction of a track section surface and a pumping bridge surface, its radial movement would be suddenly reversed and hence uncontrolled at the very instant that it was performing a maximum amount of work. Also, since the bifurcated end of a track section overlaps the reduced portion on the adjacent bridge in order to provide an unbroken path for the vanes, the end of a track section would extend above the track surface of the sealing bridge to which it was connected and the end of that bridge would extend above the track surface of the same track section and thereby form obstructions in the path of the vanes when pump displacement was at or near maximum.

In order to prevent damage to either the track or the vane and to keep the accelerations of the vanes from being excessive, the bridges are provided with concave track surfaces having a suitable radius, the track sections are provided with concave track surfaces having preferably such a radius that the track surfaces of a track section and the adjacent pumping bridge will be tangent at their junction when pump displacement is maximum and the track surfaces of a track section and the adjacent sealing bridge will be nearly tangent at their junction when pump displacement is zero, pivot pins 22 and 23 are arranged as far radially outward as may be convenient within the available space, the concave surfaces on each track section and the adjacent sealing bridge are joined by a convex surface when pump displacement is maximum, and the concave surfaces on each track section and the adjacent pumping bridge are joined by a convex surface when pump displacement is minimum so that the concave track surfaces on a track section and one adjacent bridge are joined by a smooth transition curve when the track surfaces on that section and the other adjacent bridge are tangent or nearly tangent. The radii of the track surfaces may be determined in a manner to be presently explained. The transition curve causes the vanes to move radially as they pass over it but the curve is such that the accelerations and decelerations of the vanes at this point are well within the permissible limits. With this arrangement, the radial movement of a vane is very little when it is performing a maximum amount of work, that is, when pump displacement is maximum and the vane is passing across a pumping bridge.

The convex track surfaces may be formed upon the vane tracks but, for the purpose of illustration, they have been shown on the bridges and the ends of the track sections have been shown chamfered as indicated at 33 and 34 in Fig; 4 so that they will not extend above the track surfaces of the bridges.

While vane track section 8 may be formed in any suitable manner, it has been found convenient and economical to employ the method disclosed in Patent No. 2,467,121.

The concave portion of the track surface on each bridge is preferably circular so that a plu-' rality of bridges may be fastened to a fixture and the inner faces of all of those bridges first machined, as by boring, and then finished as by grinding to provide a smooth track surface on each bridge but it is not necessary that the concave track surface on each bridge be an exact circular arc. Each end of each bridge is rounded 7 as by grinding r otherwise to form a convex surface which is concentric with the adjacent hole 26 or 2! and is tangent to the concave surface, the convex surfaces preferably being formed after the concave surface is finished.

A method for determined the radii of the track surfaces on the bridges and the track sections of a hydrodynamic machine, such as the pump shown in Fig. l, is illustrated in Fig. 12 in which a sealing bridge and one pumping bridge, such as bridges 5 and I, are shown in the positions occupiedwhen pump displacement is zero and the other pumping bridge, such as bridge 5, is shown in the position occupied when pump displacement is maximum.

As shown in Fig. 12, the concave surface on each'bridge has a radius 5| which is slightly greater than the radius of the rotor but the radius may be and in practice sometimes is slightly less than thera'dius of the rotor. With the radius as shown and with pump displacement at zero, all of the concave surfaces on all of the bridges are concentric with but spaced slightly from the periphery 'cf the rotor and their radii extend from a center Ci which is also the axis of the rotor. When apumping bridge such as bridge 6 is in itsmaximum displacement position, the radii of its cancave surface extend from a center C2 which is spaced from center Cl a distance which for convenience is called the stroke of the pump and i's equal 'to the distance through which the bridge '6' moves from its zero displacement posi tion to its maximum displacement position.

The concave track surface on each bridge extends from one to the other of its two radii that passthr'ough the pivot pins in that bridge. As shown',- the concave surface 52 of bridge 5 extends fromradius 5% to radius 5| and the concave surface 53 on each of bridges 6 and '1 extends from radius Si to radius 5l The convex track surface on each'end of each bridge is concentric with the adjacent pivot pin and tangent to the concave surface at the radius which passes through that pin. For example, each sealing bridge, such as bridge '5, has at each end thereof a convex track surface 54 which is tangent to surface 52 at radius 5H or 5 l and has a radius 55 which is struck from the center of the adjacent pin 22, and each pumping bridge, such as bridge 6, has at each end thereof 'a convex track surface 56 which is tangent to concave surface 53 at radius 5i or 5| and has a radius 51 which is struck from the center of the adjacent pin 23;

In order that a track section may have one end of its track surface tangent to the concave surface on the adjacent pumping bridge when pump displacement is maximum, the track surface on the track section has the center of its are located at a point on the radius which extends from center C2 through the adjacent pin in the pumpin bridge and, in order that the other end of the track section surface may be tangent to the track surface on the sealing bridge, the center .p-ointis located on that radius equi-distant from the concave surface on the pumping bridge and a point on the adjacent convex surface on the sealing bridge.

1 As shown, the track surface of track section 8 had a radius 35 struck from a center C3 which is located on radius 5| equi-distant from concave surface 53 and the innermost point on the adjacent convex surface 54 so that the track surfaceof-track section 8 is tangent to surface 53 at radius 5i and is tangent to convex: surface 54 at a radius 36 which extends from center through the adjacent pivot pin 22.

The arrangement is such that thevanes have no change in rate of radial movement as they travel from one track section 8 onto surface 53 and from surface 53 onto the next track section 8 at which time the vanes are performing the maximum amount of work. The vanes traveling from a surface 52 to and along a track section 8 will move radially outward and the vanes traveling along and from a track section 8 to a surface 52 will move radially inward and the radially moving vanes will continue to move radially in the same direction while passing across convex surface 54 but at that time the vanes are performing little or no work and the radial accel-' erations and decelerations of the vanes may be readily determined and are well within the permissible limits. These accelerations and decal erations may be further reduced by moving pins 22 and 23 further outward.

When the pumping bridges are moved inward to reduce pump displacement, centers C2 and C3 will move inward with them, track sections 8 will pivot upon pins 22 and 23 and the track section parts will telescope with each other to shorten the length of the track. When the pumping bridges are moved to their zero displacement position, center C2 will coincid'e'witli' center Cl and center C3 will move close to center C! as indicated by center C3 which is the center of the are on the track section 3 which is arranged between bridges 5 and l.

As the pumping bridges move inward, one'end of the concave track surface on each track section 8 moves toward concave track surface 52' to reduce the length of the convex transition curve between the two concave curves, and the other end of the concave track section surface moves very slowly out of tangency with the ad' jacent surface 53 and into tangency with convex surface 55 which then provides a small convex transition curve between the concave curves but the transition curve on surface 55 is so short even at zero displacement 'as to be substantiall negligible. That is, the length of the convex transition curve between concave surface 53 and the adjacent concave track section surface is the distance between radius 5| and the radius 36* which extends from center C3 through the ad-" jacent pivot 23, and the length of the convex transition curve between concave surface 52 and the adjacent concave track section surface'is the circular when pump displacement is zero, except for the fact that track radius 36 has been made smaller than bridge radius 5| to produce the tangent conditions of adjacent concave and convex arcs just described. This shortened track radius 36. causes a very slight radial movement of each vane which hasno significance becausev the vaneis unloaded at this time.

In the pump shown in Fig.- 1, the intake and:

discharge ports I I and I2 are arranged at one end of the rotor and extend outward axially from re cess 9 according to the usual practice. I -his a r-.

rangernent isentirelynsatisfactory,in pumps of the sizesordinarily used but it i sinot at all sat. isfactory in large pumps for the reason t ha t' an increase in capacity does not result in a proportional increase in the area of axial ports.

The volumetric capacity of a vane pump is determined by its peripheral speed, its stroke and the diameter and length or thickness of its rotor. Since pumps are ordinarily run at the highest practical rotary speed and since increasing the diameter would increase the rubbing speed, that is the speed at-which the ends of the vanes slide along the track, increasing either the rotary speed or increasing the diameter of the rotor beyond the diameter necessary to provide sufficient metal between the shaft bore and the vane slots is not a practical way to provide large increases in volumetric capacity. Even if the diameter of the rotor could be readily increased, an increase in rotor diameter would result in only 2. proportional increase in displacement but the weight of the pump would increase in accordance with the square of the diameter.

' If the stroke of the pump should be increased enough to cause the pump to have a large displacement, the vanes in contact with thepumping bridges would extend so 'far from the periphery of the'rotor that vanes of proper thickness would be bent or broken by the high pressure created by the pump, the thickness of a vane being limited due to the fact that, when a vane is passing across a pumping bridge, high pressure acts upon the full area of the inner end of the vane but acts upon only about one half of the area of the outer end of the vane so that the pressure acting upon the differential area forces the vane against the bridge and, if the vane should be too thick, it would be urged against the bridge with such force that excessive wear of the bridge and vane would result and the eificiency of the pump would be reduced. Consequently, increasing the stroke to obtain a large displacement is impractical.

Increasing the length of the rotor causes a proportionalincrease in the displacement of the pump but the space between the periphery of the rotor and the vane track remains unchanged so that the area of axial ports cannot be increased but the flow through the port must increase in proportion to the increase in displacement. Consequently, liquid cannot flow through an axial port to and from the space between the rotor and the vane track of a large capacity pump without excessive head losses. In fact, a large pump could not draw liquid from an adjacent reservoir through an axial port fast enough to keep the space between its rotor and vane track completely filled with liquid.

In order to prevent such head losses in large capacity pumps, radial ports such as shown in Fig. 2 are provided. The pump shown in that figure has two diametrically opposed intake ports Il two diametrically opposed discharge ports [2 and four vane track sections 58 which correspond, respectively, to ports I l and I2 and track sections *8, only two of the track sections and only one of each of the pump ports being shown in Fig. 2.

Each track section 58 has an opening or port 59 (Fig. 8) which extends radially therethrough to provide communication between the adjacent port H- or l2 and the space between the rotor and the vane track. Ports 59 may readily be made large enough to permit a free flow of liquid to and from the rotor and thereby avoid any substantial head loss.

For the purpose of illustration; ports ll and 12* have been shown as extending radially outward through the pump casing Ill but the outer part of each may extend in any direction as it is only necessary that the flow be radial to and through the track section. The radial arrangement of pump ports forms no part of the present invention but is claimed in a separate application.

Vane track sections 58 are similar to vane track sections 8 in that each is extensible and is provided in its opposite ends with notches 18 and l9 which correspond to notches I8 and I9 and permit the track section to overlap reduced bridge portions Ic and H which correspond to bridge portions it and El respectively, the ends of the track sections being chamfered and the ends of the reduced bridge portions being provided with convex track surfaces as'previously explained. Also, track section 58 has been shown provided at its ends with holes 2ll and 21* to receive pins 22? and 23 by means of which it is shown connected to the reduced portions 16* and W of adjacent bridges at points spaced the same distances from the track surface that pins 22 and 23 are spaced therefrom but in large size pumps each track section is provided at its ends with a longer projection by means of which it is pivoted to adjacent bridges at greater distances from the track surface. I

Each track section 58 includes a pair of principal parts and El and two arcuate guide segments 62 and 63 which are U shaped in crosssection and hold parts 60 and BI in alinement with each other while permitting them to move relatively to each other in a circumferential direction to vary the length of the vane track.

The adjacent ends of track section parts 60 and 61 are complementary to each other and so shaped as to provide an unbroken pathfor the end of a vane passing along the track surface from one part to the other. As shown, part 60 has two oppositely inclined end faces 64 and part 6| has two oppositely inclined faces '65 which extend from openings 59 to opposite sides of the track.

Each pair of parts and 61 has two grooves 66 and 61 formed in each side or edge thereof concentric to but spaced from the track surface and from each other so as to leave a rib 68 between the two grooves. Each of guide segments 62 and 63 is made U shaped in cross section and of such size and shape that it will fit into grooves 66 and 6'] and rib 68 will fit into the'segment. Two segments 62 and 63 are applied to opposite sides of a pair of parts and fastened, as by means of a pin 69, to one part, such as part 6|.

The arrangement is such that, when a track section 58 is pivotally connected at its ends to adjacent bridges and one of the bridges is moved relatively to the other to vary the length of the vane track, one of the track section parts will slide upon guide segments 62 and E3 which will keep the two parts in circular alinement so that no support for the track section is needed other than the pivotal connection at its ends.

The invention herein set forth is susceptible of various modifications and adaptations without departing from the scope of the invention which is hereby claimed as follows:

1. A vane track for a vane type hydrodynamic machine comprising a plurality of bridges and an equal number of extensible vane track sections formed separately from said bridges and arranged alternately with said bridges to form an endless vane track, each of said track sections connectera's-ass 1 1 ing adjacent bridges to each other and comprising two parts which telescope with each other so that the length of said track may be varied by adjusting one or more of said bridges.

2. A vane track for a vane type hydrodynamic machine comprising a plurality of bridges and extensible vane track sections connecting adjacent bridges to each other and forming with said bridges an endless vane track, each of said track sections having opposite ends thereof pivoted to adjacent bridges and being divided into two parts which telescope with each other so that the length of-said track may be varied by adjusting one or more of said bridges.

3; A vane track for a vane type hydrodynamic machine comprising four bridges arranged -90 apart, four vane track sections arranged between said bridges and forming therewith an endless vane track, and means for pivotally connecting opposite ends of each section to adjacent bridges, each of said sections comprising two parts which telescope with each other so that the length of said track may be varied by adjusting two or more of said bridges.

'4. A vane track for a vane type hydrodynamic -machine comprising four bridges arranged 90 apart, four vane track sections arranged between said bridges and forming therewith an 'endless vane track, and means for pivotally connecting opposite ends of each section to adjacent bridges, each of said sections comprising 'two parts which telescope with each other so that the length of said track may be varied by adjusting two or more of said bridges, and the adjacent ends of said section parts being so shaped as to provide an unbroken track for the vanes of said machine.

5., A vane track for a vane type hydrodynamic machine comprising a plurality of bridges and extensible vane track sections formed separately from said bridges and connecting adjacent bridges to each other to form with said bridges an endless vane track, each of said track sections comprising two parts which telescopewith each other so that the length of said track may be varied by adjusting one -or more of said bridges, and each of said track sections having "an opening extending radiallythereth'roujgh to provide a port through which liquid ma'y'fiow radially to and from the interiorof s'aidin'achine.

6. A'va'ne track for a variefty'p'e hydrodynamic machine compasses pluralitybf bridges each 6f which has formed thereon a track surface which is concave intefinediateits'eiids and conadjacent its ends, and a "plurality of track "sections each orwmch is pivotally ccnnected to adjacent bridges and preview with "a "concave "track surface which tangentatits'ends to the track surfaces onthe'biidge's 'to which it is cannected, each ofsaid track sections'including two relatively movable partsand said 'mbvable parts being extensible in respect to "eachoth'er 'to per- Init one bridge to be a djuste'd whil'etheadjacnt bridges remain stationary. v

'7. A vane track for 'a'vane type hydrodynamic machine comprising a plurality bf bridges each of which has formed thereon a "tracksurface which is concave intermediate its ends and conve'xadjacent its ends, and "a plurality of track sections each of which is 'pivotally'connected to adjacent bridges and provided with a concave track surface which is tangent at its'ends toth'e track surfaces on the bridges towhich'it'is'com nected, all ofsaid track surracesconsistingentirely of circular arcs and each "of said track sections including two relatively "movable p'a'rts 1 2 and said movable parts being extensible in respect to each other to permit one bridge to be adjusted while the adjacent bridges remain stationary.

8. A vane track for a hydrodynamic machine comprising at least one pair of bridges, one bridge of each pair being adjustable to vary the displacement of said machine, an equal number of track sections each of which is pivotally connected to adjacent bridges, a concave track surface on each track section, a concave track surface on each bridge, and convex track surfaces tangentially connecting adjacent concave track surfaces to provide a vane guiding surface smoothly continuous at all displacements of said machine, each of said track sections including two relatively movable parts and said movable parts being extensible in respect to each other to permit one bridge of a pair to be adjusted while the other bridge of that pair remains stationary.

9. A vane track for a hydrodynamic machine comprising at least one pair of bridges, one bridge of each pair being adjustable to vary the displacement of said machine, an equal number of track sections each of which is pivotally connected to adjacent bridges, a concave track surface on each track section, a co'n'cavetrack surface on each bridge, and convex track surfaces tangentially connecting adjacent concave track surfaces to provide a vane guiding surface smoothly continuous "at all displacements of said machine, each of said vane track sections comprising two parts provided with guide surfaces which are complementary to each other and are concentric with the track surface thereon to make each track section extensible and thereby permit one bridge of apair to be adjusted while the other bridge of that pair remains stationary.

10. In a hydrodynamic machine having vanes arranged substantially radially in a rotor and a plurality of bridges arranged around said rotor and forming'parts of an endless track for said vanes, 'the combination of an arcuate extensible vane track section connected to adjacent bridges 'and including two track parts each of which is provided with an arcuate-grooveforming in eifect a continuation of the groove in the other of said track parts, and an arcuate guide segment fitte d in said grooves to hold said parts in circumferential aline'm'ent while permittingone of said adjacent bridges to move relatively to the other.

11. In a hydrodynamic machine havingvanes arranged substantially radially in a rotor and'a plurality of bridges arranged around said rotor and forming parts of an endless track for said vanes,'the combination of an 'arcuate extensible vane track section connected to'adjacent bridges and including two track parts each of which is provided with anareuete groove'forming in efiect a continuation 6f the groove in'the other of said track'p'a'rts, and an arcuate guide'seg'fne'nt fitted in said g'r'oove's tohold said-parts incir'cumfe're'ntial alininnt while permitting one of said adjacent bridges to move relatively to the other,th' adjacent 'ends 'of the two parts'of said section being so shaped as to provide an unbroke'n'track for said vanes.

12. In a vane'type hydrodynamic machine having a rotor, the combination of 'a sealing bridge normally arranged close to said'rotor and having a track surface'whichis concave intermediate its ends and isconvex adjacentits'en'ds, a working bridge movable toward and fromsaid'rotorto vary the displacement of said machine 'b't'wee'n minimum and maximum and having a concave track surface formed thereon, and an extensible track section including two relatively movable parts and pivotally connected to both of said bridges and provided with a circular track surface having such a radius that when the working bridge is in its maximum displacement position and the sealing bridge is in its normal position the track surface on said track section is tangent to the concave track surface on said working bridge and is tangent to the track surface on said sealing bridge.

' 13. In a hydrodynamic machine having vanes arranged substantially radially in a rotor and a plurality of bridges arranged around said rotor and forming parts of an endless track for said vanes, the combination of an arcuate extensible vane track section connected to adjacent bridges and including two track parts each of which is provided with an arcuate groove which is T shaped in cross-section and forms in effect a continuation of the groove in the other of said track parts, and an arcuate guide segment which is T shaped in cross section fitted in said grooves to hold said parts in circumferential alinement while permitting one of said adjacent bridges to move relatively to the other.

14. In a hydrodynamic machine having a rotor and vanes arranged substantially radially in said rotor, the combination of a plurality of bridges arranged around said rotor, and a plurality of arcuate extensible track sections arranged between and connected to said bridges to form therewith an endless vane track; each of said track sections being provided with a radial port for the flow of liquid to and from said rotor and each track section including two track parts one of which is provided in opposite sides thereof with arcuate grooves having radially opposed bearing faces and the other of which has arcuate 1 guide segments fitted in said grooves to hold the two parts of that track section in alinement while permitting relative movement between the two bridges to which that track'section is connected.

15. A vane track for a vane type hydrodynamic machine comprising a plurality of bridges and extensible vane track sections connecting adjacent bridges to each other and forming with said bridges an endless vane track, the radially inward faces of said sections being finished to a radius less than the radius of said rotor and each of said track sections comprising two parts which telescope with each other so that the length of said track may be varied by adjusting one or more of said bridges.

16. In a hydrodynamic machine having vanes arranged substantially radially in a rotor and a plurality of bridges arranged around said rotor and forming parts of a track for said vanes, the combination of an arcuate two-part vane track section arranged between adjacent bridges and provided with an arcuate groove, means for pivotally connecting opposite ends of said track section to said adjacent bridges, an arcuate guide segment fitted in said groove to hold said parts in alinement while permitting one of said adjacent bridges to move relatively to the other, and means for fixing said segment to one of said section parts.

1'7. In a hydrodynamic machine having vanes arranged substantially radially in a rotor and a plurality of bridges arranged around said rotor and forming parts of an endless track for said vanes, the combination of an arcuate two-part vane track section connected to adjacent bridges and having an arcuate groove formed in both parts of said section, and an arcuate guide segment fitted in said groove to hold said parts in alinement while permitting one of said adjacent bridges to move relatively to the other, the radially inward face of said track section being finished to a radius less than the radius of said rotor. 1

18. In a hydrodynamic machine having a roto and vanes arranged substantially radially in said rotor, the combination of a plurality of bridges arranged around said rotor, and a plurality of arcuate two-part track sections arranged between and connected to said bridges to form therewith an endless vane track, the radially inward faces of said track sections being finished to a radius less than the radius of said rotor and each of said track sections being provided with a radial port for the flow of liquid to and from said rotor, one part of each track section being provided in opposite sides thereof with arcuate grooves having radially opposed bearing faces and the other part of that section having arcuate guide segments arranged upon opposite sides thereof and. fitted in said grooves to hold the two parts of that track section in alinement while permitting relative movement between the two bridges to i which that track section is connected.

19. In a hydrodynamic machine having a rotor and vanes arranged substantially radially in said rotor, the combination of a plurality of bridges arranged around said rotor, and a plurality of arcuate two-part track sections arranged between and connected to said bridges to form therewith an endless vane track, the adjacent ends of the two parts of each track section being so shaped as to provide an unbroken path for said vanes and each of said track sections being provided with a radial port for the flow of liquid to and from said rotor, one part of each section being provided in opposite sides thereof with arcuate grooves having radially opposed bearing faces and the other part of that section having arcuate guide segments arranged upon opposite sides thereof and fitted in said grooves to hold the two parts of that track section in alinement while permitting relative movement between the two bridges to which that track section is connected.

20. In a vane type hydrodynamic machine, the combination of a rotor having vanes arranged substantially radially therein, a structure enclosing said rotor and provided with passages for the flow of liquid to and from said rotor, and a vane track arranged within said structure and around said rotor to engage the outer ends of said vanes, said vane track including a plurality of bridges at least one of which is adjustable to vary the displacement of said machine and a plurality of extensible vane track sections arranged between and pivoted to said bridges and having openings of substantial area extending radially therethrough to provide communication between said rotor and said passages so that liquid may flow radially to and from said rotor and thereby avoid excessive head losses in machines of large capacities.

21. In a vane type hydrodynamic machine, the combination of a rotor having vanes arranged substantially radially therein, a structure enclosing said rotor and provided with passages for the flow of liquid to and from said rotor, a plurality of vane track bridges arranged around said rotor within said structure, means for adjusting at least one of said bridges to vary the displacement mgsssnes vane #trac-k :sections connecting .said bridges to each :other to form therewith an endless track for the outer ends of said vanes, each of .said vane vtrack .sections having an opening JOf vsubstantial ,area extending vradially therethrough to Iprovide communication between said rotor and said :passages so that liquid may'flow'radially to and from said rotor and thereby avoid excessive head losses .111 machines of largecapacities.

WALTER .-F.ERRIS.

REFERENCES CITED Number N umber' 16 UNITED STATES PA'I'ENTS Name Date Centervall Aug. '18, 1942 Wainwright Aug. 3, 1920 Calzoni Oct. 8, 1935 Centervall .'Dec. 27, 1938 Kucher May 27, 1941 Kucher Aug. 25, 1942 Kendrick et a1 Mar. 9, 1943 Kendrick etal. Mar. 9, 1943 Kendrick Nov. 30, 1943 Kendrick Jan. 30, 1945 Ferris Apr. '12, 1949 FOREIGN PATENTS Country Date Great Britain Dec. '18, 1924 Italy 1939

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