US3599656A

US3599656A - Variable fluid transducer

Info

Publication number: US3599656A
Authority: US
Inventors: Charles R Pettis Jr
Original assignee: Hi Speed Checkweigher Co Inc
Current assignee: Hi Speed Checkweigher Co Inc
Priority date: 1968-11-19
Filing date: 1968-11-19
Publication date: 1971-08-17
Anticipated expiration: 1988-08-17

Abstract

A variable fluid transducer adapted to produce a fluid output signal which is variable with respect to the position of a core freely movable within the transducer.

Description

United States Patent Charles R. Pettls, Jr.

Ithaca, NY.

Nov. 19, 1968 Aug. 17, 1971 Hi-Speed Checkweigher Co., Inc. Ithaca, N.Y.

Inventor App]. No. Filed Patented Assignee VARIABLE FLUID TRANSDUCER 9 Claims, 12 Drawing Figs.

US. Cl 137/83, 91/3 Int. Cl F15b 5/00, F1511 13/02,G05d 16/00 Field of Search 137/83;

References Cited UNITED STATES PATENTS 11/1957 Markey.. 137/83 2/1965 Bauer..... 235/201 X 10/1969 Hatch.. 137/6242 X 3/1946 Todd 137/83 7/1955 Weisenbach 137/83 X 8/1956 Harris 91/3 X 9/1961 Ringgenberg 251/329 X 3/1963 Moosmann 137/83 10/1968 H111 137/83 Primary Examiner-Alan Cohan Attorney- Bean and Bean ABSTRACT: A variable fluid transducer adapted to produce a fluid output signal which is variable with respect to the position ofa core freely movable within the transducer.

PATENIED M18! 7 l9?! SHEEI 2 BF 2 1 INVEN TOR. CHARLES R. PETT/S gm gm ATTORNEYS VARIABLE FLUID TRANSDUCER SUMMARY OF THE INVENTION In its broadest aspect, the fluid transducer of the present invention includes a transducer body having a cavity, a fluid supply passageway having an opening in flow communication with the cavity, a fluid signal passageway having an opening in flow communication with the cavity; and a core, which is adapted to be connected to an art device and be receivable within the cavity for movement with respect to the passageway cavity opening. Movement of the core with respect to the passageway cavity openings determines the quantity of fluid passing therebetwecn so as to produce a fluid output signal which is variable in accordance with core movement.

The invention anticipates that the characteristics of the output signal may be selectively varied by appropriately correlating the geometry of passageway cavity openings and/or the core.

In a modified form of the present invention, two or more supply and signal passageway cavity openings may be provided which cooperate with the core to simultaneously or sequentially produce a plurality of fluid output signals.

The transducer of the present invention has utility in diverse arts, which by way of general example include arts wherein a sensed condition is to control feeding of material and arts wherein a sensed condition is to effect a physical movement. In the first instance, a noncontacting core could be freely moved within thetransducer in accordance with the deflection of a weighing scale on which material is being deposited and the transducer employed to produce an output signal serving to stop or otherwise control the feed of material onto the weighing scale. In the second instance a core could be moved within the transducer in a manner determined by a master pattern or control and the transducer employed to produce an output signal serving to control movement of a tool, such as a cutter, punch or drill. Where, as in the latter instance, frictional forces are not detrimentalto the performance of'the transducer, the core may be mounted for contacting or guiding movement with the walls of the transducer cavity.

The nature and mode of operation of the transducer-of the present invention will be more fully understood by reference to the following description taken with the accompanying drawing wherein: f FIG. ,I is a perspective view of the variable fluid transducer according to the present invention;

FIG. 2 is a perspective view of the transducer shown in FIG. I, but with body sections of the transducer separated;

FIGS. 3-3b are sectional views taken generally along the line 3-3 in FIG. I, but showing the transducer core in various positions; and

FIGS. 44f illustrate exemplary transducer output signals obtainable by varying the configuration of the fluid supply cavity opening and/or the core.

DETAILED DESCRIPTION The variable fluid transducer according to the preferred embodiment of the present invention, which is designated as 1 in FIG. I, generally includes a suitably shaped transducer body 2, which is conveniently formed with body sections 4, 5;

and a core or blade 6, which is adapted to be connected to a suitable art device, not shown, which in turn determines straight line reciprocating movement of the core with respect to the transducer body 2.

While not limited thereto, the art device may be a conventional material weighing scale or pan, which is adapted to be moved vertically in accordance with the weight of material fine feed of material onto the scale in accordance with core movement. By mounting the core for noncontacting movement within the transducer no errors due to frictional forces are introduced into the weighing system.

Referring particularly to FIGS. 1 and 2, it will be seen that transducer body sections 4 5 have machined facing surfaces 8, 9, which are normally maintained in fluidtight abutting engagement by machine screws, not shown. The machine screws may be received within pairs of upper and lower stepped

bore openings

10, 12 of body section 4 and threadably received within pairs of upper and lower tapped holes l3, l5, respectively, of body section 5. Further, body sections 4, 5 are provided with lengthwise extending slots 16, 17, respectively, which when the sections are assembled, cooperate to define a transducer body cavity or slot 18 adapted to freely receive core 6 for reciprocating movement lengthwise thereof.

Again referring to FIGS. 1 and 2, body section 4 is shown as being bored through surface 8 to define a fluid supply inlet opening 20 and a main or primary fluid signal outlet opening 22, into which suitable fluid conduits 20a, 22a, respectively, are adapted to be inserted. Surface 8 is also provided with a blind opening 24 and aligned slots 26, 28, which serve to connect the inwardly extending ends of

openings

20, 22, respectively, with body cavity 18.

Also, in FIGS. 1 and 2 body section 5 is shown as being bored through surface 9 to define a secondary fluid supply chamber opening 29 and a secondary fluid signal outlet opening 31 into which a suitable fluid conduit 31a is adapted to be inserted. Opening 29 may be connected to suitable pressure monitoring equipment, not shown, or have its outer end closed, as desired. Surface 9 is also provided with a blind opening 33, a slot 35 acting to connect blind opening 33 to chamber opening 29, a closed end slot 37 in communication with cavity 18, and aligned

slots

39, 41 which connect the inwardly extending ends of openings 29, 31, respectively, with body cavity 18.

It will be understood that when surfaces 8 and 9 are disposed in abutting relationship-, the inner end of supply inlet opening 20 is axially closedbybIindopening 33 and slot 26 is laterally closed by surface 9, so as.-t o"define a supply fluid inlet passageway placing conduit 20a in flow communication with cavity 18 through a main or primary supply cavity opening 42, shown in various configurations in FIGS. 4-4f. Further, the inner end of outlet opening 22 is axially closed by surface 9 and shot 28 is laterally closed by slot 37, so as to-define a fluid signal outlet passageway placing conduitZZtz-in .flow communication with cavity 18 through a main or primarysignal cavity opening 43, shown in FIGS. 33b. Also, as will be seen from viewing FIGS. 2 and 3, surface 8 serves to'close the inner end of outlet opening 31 and to laterally close slot 41 in order to define a secondary fluid signal passageway placing conduit 31a in flow communication with cavity 18 through secondary signal cavity opening 45. In a like fashion, blind opening 24 choses the inner end of chamber opening 29 and surface 8 laterally closes

slots

35 and 39, so as to define a secondary fluid supply passageway placing the inner end of opening 20 in alternate flow communication with cavity 18 via slot 35 chamber 29 and slot 39. Slot 39 opens directly into cavity 18 through a secondary supply cavity opening 44, which is shown only in FIG. 4f.

It will be understood that in the preferred embodiment of transducer 1, the primary and secondary signal cavity openings are disposed in alignment with the primary and secondary supply cavity openings so as to permit the former to receive jets of pressurized supply fluid issuing from the latter openings. Also, a pair of opposed supply and signal cavity openings are preferably similarly shaped or configured, although they may vary'in relative size. Although not limited thereto, the supply fluid employed is preferably air.

In FIGS. 1 and 3-3b, core 6 is shown as being in the form of a thin blade having a leading control edge 50 and a vertically upwardly spaced side opening notch 51, which defines a trailing edge 52 and a secondary control edge 53. The distance between

edges

50, 52 and 53 will be determined by both the spacing between and the sizes of the cavity passageway openings, as will hereinafter become apparent.

The operation of transducer 1 will be best understood by referring to FIGS. 3-31) and 4, wherein the cavity passageway openings are illustrated as being of generally rectangular configuration and leading control edge 50 is arranged in a right angular relationship with respect to the direction of movement imparted to core 6 by the art device with which it is associated. In FIG. 3, transducer core 6 is shownas being in its rest or initial position, wherein primary and secondary streams of the supply fluid flow unobstructed by the core from the supply cavity openings across cavity 18 and into signal cavity openings 43, 45. This produces constant, maximum fluid flow output signals, which in the case of the primary output signal is shown in FIG. 4 as being at a curve point A on a graph plotting signal flow volume or pressure vs. the dimension of supply cavity opening 42 in a direction lengthwise of cavity 18. It will be understood that thesignal output curve shown in FIG. 4, as well as those shown in subsequent Figures to be discussed, may alternatively be plotted using the lengthwise dimension of the signal cavity opening assuming that pairs of supply and signal cavity openings are aligned and similarly configurated.

However, in a situation where the openings are of different configuration, or alternatively wherein plural signal cavity openings are supplied with fluid passing through a single supply cavity opening, the curves would be more accurate when plotted against the lengthwise dimension of the signal cavity opening.

It will be apparent that as core 6 is moved within cavity 18, as indicated by arrow 60 in FIGS. 3a, 4, core 6 will progressively cover supply cavity opening 42 until such opening is disposed between the leading control edge 50 and trailing cdge52. The described movement ofcore 6 serves to progressivelyreducc the flow ofsupply fluid into signal cavity opening 43 to some minimum value, such as zero, thereby tracing a fluid signal curve AB, which is linear and proportional to the travel ofcore 6.

- At this point of core travel illustrated in FIG. 3a, the primary fluid stream passing between supply cavity inlet 42 and signal cavity inlet 43 is completely bloclted, but the secondary fluid stream is permitted to pass into secondary signal cavity inlet 45. Thereafter, during continued movement of core 6 in the direction indicated by arrow 60 into its position illustrated in FIG. 3b, the secondary stream is progressively blocked due to the movement of second control edge 53 thereacross until such time as the secondary signal control flow is reduced to substantially zero. In the embodiment shown, the distance between leading control edge 50 and trailing edge 52 is suffi' cient to prevent uncovering of supply cavity inlet 42, during blocking of the secondary stream as described. Supply fluid issuing from the primary and secondary supply cavity openings will be diverted by core 6 and flow into the atmosphere surrounding transducer 1 through the ends of cavity 18. In environments wherein frictional forces are not detrimental to the operation of the transducer, so as to permit the core to be slidably supported within the transducer cavity, the core could be provided with bleed passageways to convey the diverted supply fluid to the atmosphere.

While signal output flow through openings 43 and 45 have been described as becoming zero when their associated supply cavity openings have been covered by core 6, as a practical matter there will be some minimum signal output flow. Possible disadvantages of this terminal signal flow condition may be overcome by adjusting the apparatus or fluidic circuit to which the signal output flow is directed to be nonresponsive to the terminal portion of the signal curve AB.

It will be noted that in the specific embodiment shown, the primary supply and signal openings have a dimension in the direction of core movement which is in excess of that of the secondary openings, thereby rendering the secondary signal more sensitive to core movement. This arrangement is particularly advantageous in systems such as weighing systems,

wherein the primary signal may be employed to control bulk feed and the secondary signal employed to control fine feed to bring a batch of material up to a desired weight. When employed in a weighing system it is preferable to initiate the secondary control signal curve immediately prior to completion of the bulk feeding operation, so that there will be no time delay between the bulk and fine feeding operations. In this situation the spacing between cavity openings and/or the width of opening 51 would be such as to permit initiation of the blocking of the secondary stream prior to the completion of blocking of the primary stream.

FIGS. 4a and 4b indicate how the basic linear fluid signal curve AB obtained with rectangular supply cavity inlet opening 42 of FIG. 4, may be varied for example by providing a circular opening 42a or triangular opening 42b. Circular opening 42a would have utility for controlling high speed operations which are required to be both initiated and terminated at a relatively slow speed or rate of change. Triangular opening 42b has utility'wherein the operation to be controlled requires a high speed start and relatively slow stop. For purposes of comparison, supply cavity inlet openings 4040b are shown in FIGS. 4-4b as being of equal area so as to produce equal volume, nonobstructed flow therethrough. Thus, it will be apparent that by correlating the configuration of the core with the configuration of the cavity openings the shape of signal curve AB and/or the rate of change of the fluid signal as a function of core displacement may be selectively controlled.

FIG. 4c illustrates how the basic linear fluid signal curve A--B may be varied by modifying by forming core 60, with a tapered leading control edge 50c, which is inclined with respect to the direction of core travel. With the configuration shown, initial curve portion AA and final curve portion A"-B will be similar to that obtained from the arrangement shown in FIG. 4!), whereas intermediate curve portion A- A" will be linear and correspond to that obtained in the arrangement shown in FIG. 4.

FIG. 4d illustrates a modified core 6d, wherein the leading control edge 50d is formed in the shape of a wedge. With this configuration the curve AB is similar to that obtained with the arrangement shown in FIG. 40. It will be apparent that by shaping the control edges of

cores

6c and 6d in the manner described, a fluid output signal may be obtained over a greater length of core travel, than is possible when employing a blunt control edge configuration of core 6 shown in FIG. 4.

FIG. 42 illustrates how the basic signal curve AB may be varied by providing a core 6e with a spacing between control edge 50c and trailing edge 52a which corresponds to the lengthwise dimension of supply cavity opening 42 and reciprocating core 6e through a distance corresponding to at least twice such lengthwise dimension. With this arrangement, supply fluid flow is progressively reduced to some minimum value, such as zero, along curve AA', whereafter flow is again increased as indicated by curve portion A"-B. This curve may be readily subject to variation, as for instance, by changing the point of initiation of the curve portion A"'-B by increasing or decreasing the distance between leading edge 509 and trailing edge 520 or by decreasing the distance through which core 6e is moved.

FIG. 4f illustrates additional possible modifications in the operation of the present transducer. Firstly, in this arrangement

supply cavity openings

42 and 44 are initially closed, so as to produce a signal curve which varies from some minimum value, such as zero, to a maximum value when core 6f is reciprocated in a direction indicated by arrow 60 to uncover the supply cavity openings. Secondly, a first fluid output signal represented by the curve Al--Bl, produced by flow from supply cavity opening 42, and a second fluid output signal represented by the curve, produced by flow from supply cavity opening 44 is combined in a stepwise manner to obtain a composite output signal represented by curve A,B,. The construction of core 6f differs from that of core 6 in the provision of a second side opening notch 51 which permits unbloclcing of supply cavity opening 44. It will be apparent that control signal curve A,-B, may be further modified by tapering or otherwise shaping the trailing edges of one or both of side opening slots 5 1 f and 51f It will be understood that the fluid signal curves A-B described hereinabove are merely exemplary and that the signal curves may be tailored to meet the needs of the apparatus or fluidic circuit which is to be controlled by the output signal or signals produced by the transducer. Further, it will be understood that in actual practice various flow phenomena will cause departures from the ideal fluid signal curve shapes illustrated in the drawings.

While there has been described in detail a transducer having the capability of producing two sequentially modified fluid output signals, it will be understood that variations thereof will become apparent to those skilled in the art in view of the foregoing description. Exemplary thereof would be to provide a transducer having a single output signal, a transducer having a single supply cavity opening furnishing fluid to plural signal cavity openings, or a transducer having a capability of three or more output signals to be varied in any desired fashion. Further, while the transducer has been described as accommodating a core having straight line reciprocating movement, it; will be apparent that if desired, the transducer may be modified to permit'pivotal, rotational or other core movements produced by the art device with which the core is associated. Still further, while the core has been specifically described as being connectable to an art device for movement therewith relative to a stationary transducer body, it will be readily apparent that the core may be stationary and the transducer body connected to the art device or the core and transducer body connected to simultaneously movableparts of the same or dissimilar art devices.

Accordingly, it is wished that the scope of protection awarded on my invention be limited only by the scope of the appended claims; wherein:

lclaim:

1. A fluidic transducer for producing fluidic circuit controlling output signals variable in accordance with the movement of an art device with which the transducer is associated, the transducer comprising:

a transducer body portion having body sections, said body sections having surface portions joined in abutting engagement, said surfaces cooperating to define a cavity opening adjacent opposite ends thereof to the at- -mosphere, an opening for supply air in flow communication with said cavity and at least two signal cavity openings; and

a core, said core being receivable within said cavity through one of said open ends thereof for reciprocating movement along a straight line path, said signal cavity openings I being spaced apart in a direction aligned with the path of core movement, one of said body portion and said core being independent of and the other of said body portion and said core being mechanically connectable to said device for movement therewith such that art device induced movement thereof effects movement of, said core relative to said signal cavity openings, so as to vary the quantity of air passing thereto and thereby produce a pair of fluidic output signals which are variable with core movement.

2. A fluidic transducer according to claim 1, wherein said core has an edge portion and a through opening, said through opening heing spaced from said leading edge in a direction aligned with said path of core movement and defining a second edge portion, said edge portions cooperating one with each of said signal cavity openings to vary the quantity of air passing therethrough.

3. A fluidic transducer according to claim 2, wherein one of said signal cavity openings has a dimension in a direction aligned with said path of core movement in excess of a similar dimension of the other of said signal cavity openings.

4. A fluidic transducer according to claim 1, wherein there is provided at least two pairs of supply and signal cavity openings, said openings of each said pair being aligned and of similar configuration.

5. A fluid transducer comprising:

a transducer body portion having a cavity, a passageway for supply fluid having an opening in flow communication with said cavity and at least two passageways for signal fluid having openings in flow communication with said cavity; and

a core, said core being receivable within said cavity for movement with respect to said cavity openings, one'of said body portion and said core being connectable to an art device for movement therewith such that art device induced movement thereof effects movement of said core relative to said cavity openings so as to vary the quantity of fluid passing therebetween and thereby producing fluid output signals in said signal passageways which are variable with core movement, said signal cavity openings being spaced apart in the direction of core movement and the dimension of one of said signal cavity openings in the direction of core movement being greater than a similar dimension of the other of said signal cavity openings.

6. A fluid transducer comprising:

a core, said core being receivable within said cavity for movement with respect to said cavity openings, one of said body portion and said core being connectable to an art device for movement therewith such that art device induced movement thereof effects movement of said core relative to said cavity openings so as to vary the quantity of fluid passing therebetween and thereby producing fluid output signals in said signal passageways which are variable with core movement, said signal cavity openings being spaced apart in the direction of core movement, said core having a first edge portion and a second edge portion spaced from said first edge in a direction aligned with the direction of core movement whereby movement of said core in a first direction serves to move said first edge portion across a first of said signal cavity openings and said second edge portion across a second of said signal cavity openings to vary the quantity of fluid passing thereto.

7. A fluid transducer according to claim 6, wherein the distance between oppositely extending ends of said signal cavity openings when measured in a direction aligned with the direction of core movement is at least equal to the distance between said first and second edge portions.

'8. A fluid transducer according to claim 6, wherein the dimension of one of said signal cavity openings in the direction of core movement is greater than a similar dimension of the other of-said signal cavity openings.

9. A fluid transducer comprising:

a core, said core being receivable within said cavity for movement with respect to said cavity openings, one of said body portion and said core being connectable to an art device for movement therewith such that art device induced movement thereof effects movement of said core relative to said cavity openings so as to vary the quantity of fluid passing therebetween and thereby producing fluid output signals in said signal passageways which are variable with core movement, said signal cavity openings being spaced apart in the direction of core movement, said core is provided with a pair of through openings spaced apart in a direction aligned with the direction of core moveopenings into alignment with said signal cavity openings to increase the quantity of fluid passing thereto.

Claims

1. A fluidic transducer for producing fluidic circuit controlling output signals variable in accordance with the movement of an art device with which the transducer is associated, the transducer comprising: a transducer body portion having body sections, said body sections having surface portions joined in abutting engagement, said surfaces cooperating to define a cavity opening adjacent opposite ends thereof to the atmosphere, an opening for supply air in flow communication with said cavity and at least two signal cavity openings; and a core, said core being receivable within said cavity through one of said open ends thereof for reciprocating movement along a straight line path, said signal cavity openings being spaced apart in a direction aligned with the path of core movement, one of said body portion and said core being independent of and the other of said body portion and said core being mechanically connectable to said device for movement therewith such that art device induced movement thereof effects movement of, said core relative to said signal cavity openings, so as to vary the quantity of air passing thereto and thereby produce a pair of fluidic output signals which are variable with core movement.

2. A fluidic transducer according to claim 1, wherein said core has an edge portion and a through opening, said through opening being spaced from said leading edge in a direction aligned with said path of core movement and defining a second edge portion, said edge portions cooperating one with each of said signal cavity openings to vary the quantity of air passing therethrough.

5. A fluid transducer comprising: a transducer body portion having a cavity, a passageway for supply fluid having an opening in flow communication with said cavity and at least two passageways for signal fluid having openings in flow communication with said cavity; and a core, said core being receivable within said cavity for movement with respect to said cavity openings, one of said body portion and said core being connectable to an art device for movement therewith such that art device induced movement thereof effects movement of said core relative to said cavity openings so as to vary the quantity of fluid passing therebetween and thereby producing fluid output signals in said signal passageways which are variable with core movement, said signal cavity openings being spaced apart in the direction of core movement and the dimension of one of said signal cavity openings in the direction of core movement being greater than a similar dimension of the other of said signal cavity openings.

6. A fluid transducer comprising: a transducer body portion having a cavity, a passageway for supply fluid having an opening in flow communication with said cavity and at least two passageways for signal fluid having openings in flow communication with said cavity; and a core, said core being receivable within said cavity for movement with respect to said cavity openings, one of said body portion and said core being connectable to an art device for movement therewith such that art device induced movement thereof effects movement of said core relative to said cavity openings so as to vary the quantity of fluid passing therebetween and thereby producing fluid output signals in said signal passageways which are variable with core movement, said signal cavity openings being spaced apart in the direction of cOre movement, said core having a first edge portion and a second edge portion spaced from said first edge in a direction aligned with the direction of core movement whereby movement of said core in a first direction serves to move said first edge portion across a first of said signal cavity openings and said second edge portion across a second of said signal cavity openings to vary the quantity of fluid passing thereto.

8. A fluid transducer according to claim 6, wherein the dimension of one of said signal cavity openings in the direction of core movement is greater than a similar dimension of the other of said signal cavity openings.

9. A fluid transducer comprising: a transducer body portion having a cavity, a passageway for supply fluid having an opening in flow communication with said cavity and at least two passageways for signal fluid having openings in flow communication with said cavity; and a core, said core being receivable within said cavity for movement with respect to said cavity openings, one of said body portion and said core being connectable to an art device for movement therewith such that art device induced movement thereof effects movement of said core relative to said cavity openings so as to vary the quantity of fluid passing therebetween and thereby producing fluid output signals in said signal passageways which are variable with core movement, said signal cavity openings being spaced apart in the direction of core movement, said core is provided with a pair of through openings spaced apart in a direction aligned with the direction of core movement, said core openings being arranged to cooperate one with each of said cavity openings, whereby movement of said core in a first direction progressively moves said core openings into alignment with said signal cavity openings to increase the quantity of fluid passing thereto.