US2389709A

US2389709A - Mechanical action

Info

Publication number: US2389709A
Application number: US588461A
Authority: US
Inventors: Frederick W Anders
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-04-16
Filing date: 1945-04-16
Publication date: 1945-11-27
Anticipated expiration: 1962-11-27

Description

Nov. 27, 1945. w ANDERS 2,389,709

MECHANICAL ACTION Filed April 16,- 1945 3 Sheets-Sheet 1 IN VEN TOR. Finn/0r him 0525 ATTOP N576 Nov. 27, 1 945. E w ERs 2,389,709

MECHANICAL ACTION Filed April 16, 1945 5 Sheets-Sheet 2 INVENTOR. fire-pawn: WA/Vflffii /5 3 y Arr-a2 N: m

Nov, 21, 1945. 'F. w. ANDERS 2,389,709

MECHANICAL ACTION Filed April 16, 1945 3 Sheets-Sheet 3 INVENTOR. fifl'DER/GK W Amos/as A rromvs y:

. Patented Nov. 27, 1945 UN TED STATES FATE NT OFFICE M QHANIQA Q' Z ON Frederick W; Anders, Danville, Ill. Au icaiisznAPtit 1.6 1945,. Seth! Ne. 5.88.;fifit 6 Claims.

This invention relates to a mechanical action and. more particularly to a reciprocating and rotary action useful inv a devicev such as a pump or engine forhandling fluids or-being acted upon by fluids having self-controlled intake and dis.- charge ports.

In a broad embodiment, the invention comprises a novel mechanical action comprising at least one reciprocating piston, a cam, track; come prising at least tWo idler sections of differing diameter and concentric, with a, rotor, the idler sections being connected by cam sections, a rotor comprising radially disposed cylinders, pistons associated with said cylinders, said pistons comprising cam followers extending through an opening in the cylinder wall into operating engagement with the cam, an intake port and a discharge port engageable with the cylinders during reciprocation of the piston and cl oseable by the rim of the rotor while the piston is: a non-reciprocating position.

The cam follower extends throu h a passage in the wall of the, cylinder and engages the cam track, said cam track comprising a. segment conforming to an arc of a circle concentric with the rotor and having its outside radius equal to that of the rotor minus the len th of the piston stroke, a second segment connecting the f rst segment with a point on an arc oi a second son: centric circle having its outside radius equal to the radius of the motor minus twice the length of the piston stroke and a third segment connecting another point on the lastmentioned circle with the first mentioned segment, the two points on the smaller circle being joined by a segment of the cam.

The shell comprises at least two opposed sections containing cam tracks and bearings.

The action is useful for numerous purposes including pumping air or other gases, for example, as an air compressor or a tractor pump. When the action is used in a pump, it may be used for handling liquids of all kinds, both heavy and light, or mixtures of liquids and solids which must be fluid to be handled. In View of the fact that the volume of liquid or gas contained in the cylinder is constant, it is possible to use the ap: paratus for filling containers with measured amounts of material. This may be done by dis,- charging the material contained in a single cylinder into a container, or by discharging any predetermined multiple number of cylinders into the container.

It may also be used with the direct injection D esel ty of e i e by u ing a suitabl i jection system and ignition chamber in conjunction with the apparatus. The pump and the engine are; not equivalent except'insofar as th y employ the novel mechanical movement described herein.

h shap o he cam i mod d: t ta car of the problems incident to engines over; those encountered when using the device as a pump.

The appa s can b se as l st t d Figs. 2 and 3, as a pump, In this instance, the device is equipped with a sin lfi intake and dischar e p Wh n u d a a ump and, 1 purposes, a multiple ca rn, such as is, shown in Fig. 4, may be used.

A d u am. may e used n nec o i a pumping device or other devices described he in. By increasing the size of the device and mg the stroke and size of each piston, it is possibl to. p oduc ul i e 2am d c s ausin more than three reciprooations per piston per revolution of the rotor.

Anette: se o the nv t n s in c nn t o with the production of pulsations in pressure, for example, in gas systems The. apparatus may also be used as a vacuum pump.

Advantages of the present apparatus over. other cam actuated reciprocating rotary piston are numerous. One. lies in the compara:

tive simplicity of construction and the. conse:

quent reduction in cost of manufacture. A sec: ond advantage is that the pump is more eiiicient than the pumps which have been previously dis: closed. Prior pumps have been of extremely complex structure making them expensive to build and maintain so that they can be, used only for special industrial purposes. The present apnparatus can be manufactured in numerous sizes for a fraction of the cost and with a use of a fraotion of the material. I

Essentially, the pump consists of a rotor, re.-

ciprocating pistons a shell having inletand outlet ports which are attached to conduits, etc., in the usual way. The reciprocating action is obtained by means of cam followers associated with a readily constructed cam track. The shape e the rack is Su h that h apparatus is' riot under pressure except that which it must pump against and this only during the period of the stroke when the piston is discharging the air or other fluid. During all other times, the back pressure through the discharge port is withstood by virtue of the rim of the rotor sealing the dis.- charge port. Due to the fact that a very rapid d schar action s o tain d. wer is no neces i y or in ake o d h ro ve Q co e asst.

or chambers surrounding the rotor, as is the case with previously disclosed devices.

Another advantage lies in the fact that the discharge and intake strokes can be timed to any speed merely by varying the rate of rotation of the rotor. It can be made as slow or as fast as may be desired. At the high speeds of the discharge of materials it is practically continuous, while at the low speeds a pulsating effect canbe obtained. When used as a container filler, low speeds can be employed so as to permit the proper placing of the containers and changing them,

When using a multiple cam pump, the discharge .ports can be joined to discharge into a single line.

Another advantage lies in the fact that the apparatus can be made self-lubricating, thus eliminating the problems arising from more complex systems.

Another advantage lies in the emciency of the pump since substantially all of the fiuid is discharged from the cylinder at each stroke. The shape of the cylinder head, which conforms with that of the inner wall of the shell, permits practically complete discharge of the contents of the cylinder.

Other advantages and uses will be apparent from the following description.

Fig. 1 is a plan view of the apparatus with part of the case removed and the cam track plate in position showing the shape of the cam track and the comparative positions of the pistons during the various stages of rotation.

Fig. 2 is a section in side elevation of the device of Fig. 1 taken along lines 22.

Fig. 3 is an elevation of the assembled pump.

Fig. 4 is a plan view of an apparatus employing a triple cam, that is, one in which the intake and discharge strokes are repeated three times during a single rotation of the rotor.

Figure 5 illustrates a relief groove and hole to prevent entrapment of oil below the piston in the bottom of the cylinder.

Fig. 6 shows diagrammatically a multiple cam shape.

Referring to Figs. 1, 2 and 3, the apparatus comprises a case or shell [0 which may be made in two or more sections, a detachable head I l and a body or main portion 52. These may be made from castings or forgings which may be bolted together by conventional means such as stud bolts I3. A gasket may be provided between the two sections or other conventional meansto prevent leakage may be employed, for example, the two sections may be joined in other ways and may comprise ground surfaces so that a close fit may be obtained. In each section is a bearing, which may be needle bearings, l4 and IS in appropriate bearing housings l6 and [1 shown as integral parts of the shell l0. Where high pressure operations are employed, it may be desirable to include various types of sealing devices to prevent leakage of lubricant or fiuid through the bearing. For many purposes, such as its use in a, tractor pump, this is not necessary because the efiiciency of the pump is not materially reduced by small leakage.

Passing through these bearings and journaled,

therein is drive shaft l8. In each part of the case or shell are cam track plates l9 and 20, each containing or forming cam track 2|. The cam track plates are illustrated as recessed in the case or shell of the pump and it may be bolted or otherwise securely fastened flush with the inside thereof. In finishing the pump the plates and other internal parts of the shell must be ground or machined or otherwise fitted so that the rotor will pass over the surfaces without either undue friction or scouring, but without leakage between the rotor and. the shell.

Enclosed within the shell and attached to drive shaft ill by conventional means is a rotor 22. This may be cast or machined in a single piece or made up in sections depending on the size and use to which the pump is to be put. For smallpumps, the rotor is usually made of a single casting. The rotor contains a plurality of radial cylinders although it is possible to use a pump having a single cylinder and piston associated therewith. In most instances in order to conserve material and reduce the weight and also to reduce friction, a large part of the metal between the cylinders is eliminated so that the rotor has the appearance of a wheel with spokes radiating from the center in which the cylinders are bored. Lubricant may be placed in the interstices to lubricate the moving parts. The rim of the rotor is continuous and fits closely to the wall of the shell. It may be lubricated from within by means of a groove in the casing as hereinafter described.

In each cylinder wall, extending for the length of the stroke of the piston (allowing for tolerance) is a slot 23 which is of sufficient size to permit reciprocating movement of the pin or cam follower 30 attached to the piston. The slot is parallel to the wall of the cylinder and the length must be gaged so that the opening is always sealed by the piston to prevent fluid from escaping into the body of the pump from the cylinder and also to prevent the lubricant in the body of the pump from escaping into the upper part of the cylinders and thus be ejected from the pump.

Traveling within the cylinder is one or a plurality of

pistons

24, 25, 26, 21, 28 and 29. The piston is made up of a cylindrical body having a .pin or cam follower 39 attached thereto of sumcient length to extend through the slot 23 in the rotor so that each end engages and terminates in the cam track 2! in plates [9 and 2G. The cam followers are illustrated as pins or rollers extending through the piston walls. The follower may comprise'roller bearings. The pistons are illustrated as flush fitting with the walls of the cylinder. However, it is within the scope of the invention to out one or more channels around the piston and place one or more piston rings therein. This is a conventional treatment for piston and cylinder arrangements and need not be illustrated or described. The head of the piston is solid and convex in form, the radius being the same as that of the rotor. When the piston is at its maximum discharge stroke, it follows the contour of the shell and exactly closes the cylinder. This is a feature of the pump, since it permits complete discharge of material from the cylinder at each stroke.

The piston and the cylinder walls are lubricated since the lubricant can enter into the cylinder under the piston through slots 23. The bearings I4 and I5 may be lubricated through appropriate channels, (not shown) or grooves may be cut in the face of the rotor 22 in the region of the shaft so as to permit oil or lubricant to enter.

A groove 38 may be cut concentric with the rotor on one or both faces at a point between the shaft and the farthest retraction of the piston and a relief hole 39 may be drilled from the groove can be curved in some instances.

:into the lower ,part of each cylinder to permit lubricant trapped therein tobe ejected when the piston is retracted.

The cam track 2!, as illustrated, is made up of two plates i9 and 20 set into the face of the shell and having a space between them of sufficient width topermit cam followersSO to'travel therein as the rotor is rotated. Thesemay also be in the 'form of groovescutin a1plate,;0r may be cut in'the shell. The use :of two plates .is'advantageous since it simplifies the manufacture and replacement of parts.

The cam track illustrated in Fig. 1 has a short idler segment between-34 and 35 at which the piston is at top dead center: between the completion of the discharge stroke and the beginning of the intake stroke. Theouter edge'of the segment corresponds to the arc of a circle concentric with the rotor and having a radius equal to that of the rotor minus the length of the-stroke of the piston. The width of the groove is just enough greater than that'of the cam follower to permit its moving readily therein. This segment covers about 30 of travel. The cam changes direction zit-35 and the next segment of the cam track from 35 to 36 is preferably straight and is smoothly joined to the other segments. It is never concentric with the rotor even though it It joins the idler segment just described with the next segment (or point) and accounts for about 45 of travel.

The next segment begins at 38- and as illustrated in Fig. 1, is in the form of an arc concentric with the rotor and shell ending at 31. The outer side of the track conforms to the arc of a circle whose radius is that of'the rotorminus twice the piston stroke. As illustrated in Fig, 4, this segment is merely a point on the circumference of a circle as described. In Fig. 1 this segment accounts for about 240 of travel. It is then joined with another straight segment beginning at 3? which connects it terminally with the first mentioned segment at 34.

In Fig. 4, there are three idler sections at top dead center and three points on the smaller circle through which the cam passes during each revolution. Thus, there are three intake and three discharge strokes by each piston per revolution of the rotor.

Referring to Fig. 4, the cam track is illustrated as a symmetrical multiple cam track which results in three complete reciprocations of each piston for each revolution, Each idler section at top dead center corresponds to 30 of rotation of the.

- piston, i. e., the intake stroke; and 45 causes the, discharge stroke. The point at which the stroke changes from intake .to discharge lies on the circumference of a circle having a radius equal, to the radius of the rotor minus twice the length of the piston. stroke.

If a circle weredrawn having a widthequalto the width of the cam followers plus the necessary I tolerance, and having an outside radius .equal to that of the rotor minus the length of the pis-r ton stroke, the idler sections-of the earn-would lie on the circle. If this circle were divided into segments of 30 each lying equidistant on the .cir-

.cle, it would correspond to the three, idler. .sec- .tions of. the cam shownzin Fig. 4. .One of these 1 The outside of the. cam track is tangential to such a circle.

occupiesthespacebetween-a and b. If the terminals not these arcs were joined by straight lines, they would form the working sections of -:the cam :which cause reciprocation of the piston. One of these :straight line cam sections :lies between D and 1, which are 90 apart. The

pointed, whichis-oma; line bisecting this section .of;the;cam track represents the point atwhich the outside edge of the cam track istangential to moves into the straight segment of the cam track and-during the'travel from'b to c, the piston 2.9.iswithdrawn-resulting in the intake of .fluid throughporti32. When the rotor has trav- 20v eled topoint c,1the cylinderw has been completely withdrawn and will, be filled to capacity. During the .travelfrom 0 too, thedischarge stroke takes place. :Theileading edge of thecylinder coincides :atthis. point to thedischarge port; 33in the shell. The distance between the discharge port, and the intake port mustbe sufficient so that the .spacebeween them is: sealed by the rim of the rotor at. the time'the compression stroke is completed, In Fig.1, there is no difiiculty fromthis source since. a substantial period of the: rotation is occupied in an'idlerstrokeafter the cylinder has been completely filled. InFig. 4 there is,

preferably, a slight. compression following the completion of the intake :stroke and. the beginning of discharge of fluidfrom thecylinder in the multiple campump,-so that there is never a communication between the intake and discharge ports through acylinder. The pump of Fig. 4 is particularly useful for gases.

In Fig. 1, the straight segment of cam 3536 is tangential to the arc 363l. A..similar relationship exists in Fig.4:as described. This gives the greatest efficiency. "However, it is within the -scope-of the invention that the slope of the point of travel; a second portion 42 concentric with the rotor to maintain the piston stationary straight cam section be greater than this, so that ifeXtended; it would cut a sector through the smaller circle. This may be used to advantage in the multiple cam pump. For example, a very short idler segment at point (2 in Fig. 4

would eliminate the need: for slight compression at the beginning of: the discharge stroke. Such a shape is illustrated in Fig. 6. The cam track comprises several'cam elements, each composed of afirst portion ill concentric with the rotor and to maintain the piston stationary at its innermost at its outermost point of travel; athird portion '41 joining 4i) to42 to cause outward travel of the piston while rotating clockwise; and a fourth portion 43 joining- 42- to the next first portion 40 to cause inwardreciprocation. These elements .repeat' themselves threetimes in the embodiment illustrated inFie; 6. The positions of the .portsare as in Fig, 4.

j Indescribing the structure of the cam track, etc.. itshouldbe kept in mind that small varia- .tions for the toleranceoffit of the parts are to be .takeninto consideration.

The position and size of the intake and discharge po ts is,of. import n ee op in y .becircular. or ovoid, oriany, otherwdesired shape to the edge of the rotor and it should be short enough so that the rim of the rotor between the cylinders seals the opening before it engages with the next following cylinder. This prevents leakage of the fluid back into the next cylinder. The

usual fittings and piping attachments may be made to the discharge and intake ports by conventional means and are not shown for purposes of simplification.

The apparatus may be made from any suitable type of material. This will depend to a large extent upon the service for which it is intended. In many instances, the principal parts can be made of light alloy, such as those of aluminum or magnesium. The surfaces of the rotor, the cylinders and the piston, as well as the bearing surfaces of the shell, may be hardened by suitable known processes to withstand wear, or they may in certain instances be furnished with liners which may be replaceable. The use of piston rings is contemplated as within the scope of the invention. Moreover, various arrangements may be provided in the shell or in the rim of the rotor to more effectively seal the cylinders so as to prevent leakage of fluid through the pump. These may comprise liners of metal or plastic, rubber, synthetic resilient materials, and the like. Such devices may serve the purpose of piston rings to aid in providing more perfect sealing.

The discharge stroke begins at approximately the instant the leading edge of the cylinder is in a position coinciding with the discharge port and lasts until the cylinder has just passed the discharge port. At this point, top dead center is reached and the contour of the piston coincides exactly with the contour of the shell. The discharge -stroke occupies a period of time and a degree of rotation exactly equivalent to the time and distance required for the cylinder to pass the discharge port. It is unnecessary to use a valve onthe discharge port for the reason that the port is instantly sealed by the solid rim of the rotor after the discharging cylinder has passed the opening and prevents back flow of fluid. As soon as a cylinder coincides with the discharge port, fluid is being discharged therefrom because the discharge stroke has begun. When pumping gases, the port may be placed so that the discharge stroke begins slightly before the cylinder and the openings coincide, thus compressing the gas slightly before discharge. This will prevent any back draft.

During the idler stroke following discharge, the rim of the piston rides along the inner vertical face of the shell (see Fig. 1). At this point, it is possible to inject a small amount of lubricant through an opening 31 attached to an appropriate oiler and a vertical groove in the shell. The groove may extend across the vertical face of the shell andthen in toward the center of the shell along the cam plate as at 38.

The lubricant is thus forced centrifugally into the groove 38 and lubricates the rim of the rotor and piston and the vertical face of the shell which is difficult to lubricate otherwise because of the close fit. In this case, oil' hole 3| is closed to prevent loss of oil to the exterior. Thi is the only point at which positive lubrication of the rim can be obtained. Oil may be added to the device by pressure feeding through hole 3! and groove 38.

The invention is not intended to be limited t the exact modifications shown but includes all reasonable equivalents.

The term cam element as used herein is defined as that portion of the cam track which will produce one complete reciprocation of a piston. Thus the cam device in Fig. 1 is a cam element, as well as a complete cam track. A cam track which will cause one piston to reciprocate a multiple number of times, e. g. 2, 3, or 4, etc., per revolution of the rotor, ha a corresponding number of cam elements making up the cam track.

I claim as my invention:

1. An apparatus comprising a stationary housing, a closely fitting rotor having a shaft, a cylinder formed radially in said rotor, the diameter of said cylinder being less than the width of the rotor, opposed slots in the walls of the rotor extending into and for a part of the length of said cylinder, a piston in the cylinder, a pin associated with the piston and extending through the slots, a cam track to impart an interrupted reciprocation to the piston comprising segments of two concentric circles, one having a radius equal to that of the rotor minus the length of the piston stroke, the second having a radius equal to the radius of the rotor minus twice the length of the piston stroke, said concentric segments being joined by working segments. said cam being placed in said housing and associated with the pins so that when the piston is at the limit of its outward stroke it conforms to the rim of the rotor thereby presenting an unbroken surface. a discharge port in said housing of smaller cross-section than said cylinder and communicatable therewith only during the discharge stroke of said piston, an intake port of lesser cross-section than said cylinder and communicating therewith only during the withdrawal stroke of said piston, the rim of said rotor always sealing the space between said discharge and intake ports.

2. Apparatus comprising a shell forming a generally cylindrical cavity having circumferentially spaced fluid inlet and outlet ports, a rotor mounted for concentric rotation within said cavity, the

periphery of said rotor having substantial seal- 1 ing through said slot, a cam track positioned adjacent said end wall of said rotor to cooperate with said cam follower to impart reciprocation to said piston, a first portion of said cam track being concentric with said rotor and arranged to maintain said piston stationary relative to the cylinder at the extreme inner limit of it reciprocation during that portion of a revolution of said rotor between substantially the point at which said cylinder passes from open communication with said fluid inlet port and substantially the point at which said cylinder passes into communication with-said fluid outlet port, a second portion of said cam track being concentric with said rotor and arranged to maintain said piston stationary relative to said cylinder at the extreme outer limit of its reciprocation during that portion of a revolution of said rotor between substantially the point at which said cylinder passes from communication with said fluid outlet port and substantially the point at which said cylinder passes into communication with said fluid inlet port, a third portion, of said cam track located between said first and said second portions and arranged to move said piston from its extreme inner limit of reciprocation to its extreme outer limit of reciprocation during that portion of a revolution of said rotor in which said cylinder is in communication with said fluid outlet port, and a fourth portion of said cam track located between said second and said first portions and arranged to move said piston from its extreme outer limit of reciprocation to its extreme inner limit of reciprocation during that portion of a revolution of said rotor in which said cylinder is in communication with said fluid inlet port. l

3. An apparatus comprising a shell forming a generally cylindrical cavity having circumferentially spaced inlet and outlet ports, a rotor mounted for concentric rotation within said cavity, the periphery of said rotor having substantial sealing engagement with the cylindrical wall of said cavity but permitting rotation of said rotor relative to said shell, a cylinder extending radially inward from the periphery of said rotor, the distance between said fluid inlet and said fluid outlet ports being greater than the diameter of said cylinder, a piston reciprocable in said cylinder, a radial slot extending through an end wall of said rotor into said cylinder, a cam follower on said piston extending through said slot, a cam track positioned adjacent said end wall of said rotor to cooperate with said cam follower to impart reciprocation to said piston, said cam track comprising a portion concentric with said rotor and arranged to maintain said piston stationary relative to the cylinder at the extreme outer limit of its reciprocation, for a suflicient portion of a revolution of said rotor for a point on the periphery thereof to travel a distance greater than the diameter of said cylinder, said portion of a revolution being between substantially the point at which said cylinder passes from communication with said fluid outlet port and substantially the point at which said cylinder passes into communication with said fluid inlet port, another portion of said cam track arranged to move said piston from its extreme outer limit of reciprocation to its extreme inner limit of reciprocation during that portion of a revolution of said rotor in which said cylinder is in communication with said fluid inlet port, and another portion of said cam track arranged to move said pis-' ton from its extreme inner limit of reciprocation to its extreme outer limit of reciprocation during that portion of a revolution of said rotor in which said cylinder is in communication with said fluid outlet port.

4. Apparatus comprising a shell forming a generally cylindrical cavity having circumferentially spaced fluid inlet and outlet ports, a rotor mounted for concentric rotation within said cavity, the

periphery of said rotor having substantial sealing engagement with the cylindrical wall of said cavity but permitting rotation of said rotor relative to said shell, a cylinder extending radially inward from the periphery of said rotor, a piston reciprocable in said cylinder, a radial slot in said rotor extending through an end wall thereof into said cylinder, a cam follower on said piston extending through said slot, a cam track positioned adjacent said end wall of said rotor to cooperate with said cam follower to impart reciprocation to said piston, said cam track consisting of at least one cam element, each cam element being capable of producing one complete reciprocation per rotation of the rotor and comprising a portion concentric with said rotor and arranged to maintain said piston stationary relative to the cylinder at the extreme inner limit of its reciprocation during that portion of a revolution of said rotor between substantially the point at which said cylinder passes from open communication with a fluid inlet port and substantially the point at which said cylinder passes into communication with a fluid outlet port, a second portion concentric with said rotor and arranged to maintain said piston stationary relative to said cylinder at the extreme outer limit of its reciprocation during that portion of a revolution of said rotor between substantially the point at which said cylinder passes from communication with a fluid outlet port and substantially the point at which said cylinder passes into communication with a fluid inlet port, a third portion of said track connecting a first mentioned portion and a second mentioned portion and arranged to move said piston from its inner extreme limit of reciprocation to its outer extreme reciprocation, during that portion of a revolution of said rotor in which said cylinder is in communication with a fluid outlet port and a fourth portion of said cam track connecting a second mentioned portion and a first mentioned portion and arranged to move said piston from its extreme outer limit of reciprocation to its extreme inner limit of reciprocation during that portion of a revolution of said rotor at which said cylinder is in communication with an inlet port.

5. The apparatus of claim 4 further characterized in that the cam track consists of the four mentioned portions connected in the order named, said apparatus having one inlet port and one outlet port.

6. The apparatus of claim 4 further characterized in that the pump has a multiple number of cam elements, at least two in number, and a corresponding multiple number of inlet and outlet ports. l

FREDERICK W. ANDERS.