US 3796349 A
Apparatus for dispensing measured quantities of granular or other flowable material, including a hopper having a discharge outlet controlled by a valve member biased to outlet closing position, a pivoted latch for holding the valve member in outlet-opening position but biased to release the valve member, and a tiltable pan for receiving material discharged through the hopper outlet. A pair of mutually attracting magnetic elements respectively carried by the latch and by the pan in spaced relation to each other exert a force that both opposes tilting of the pan and holds the latch in engagement with the valve member after the valve member is moved to outlet-opening position. When the weight of material accumulating on the pan overcomes this force, the pan tips, dispensing the material, and the biased latch is released, allowing the valve member to close the hopper outlet, ending the discharge. A counterweight thereafter returns the pan to its material-receiving position. The weight of material that will tilt the pan may be selected by adjusting the relative spacing of the magnetic elements in a direction perpendicular to the direction in which the element carried by the pan moves when the pan tilts.
Claims available in
Description (OCR text may contain errors)
United States Patent  Weber [451 Mar. 12, 1974 WEIGHING DISPENSER  Inventor: Robert L. Weber, Box 217, New
Canaan, Conn. 06840  Filed: May 18, 1972  Appl. No.: 254,618
 US. Cl 222/55, 177/114, l77/DIG. 5  Int. Cl G01g 13/00  Field of Search 222/55, 56, 77, 58, 364,
222/450, 505, 508; 177/110, 114, 115, DIG. 5, 184, 185, 187, 188, 189; 214/182, 17 C; 292/2515; 24/201 B Primary Examiner-Robert B. Reeves Assistant Examiner-Francis J. Bartuska Attorney, Agent, or Firm-Cooper, Dunham, Clark, Griffin & Moran  ABSTRACT Apparatus for dispensing measured quantities of granular or other fiowable material, including a hopper having a discharge outlet controlled by a valve member biased to outlet closing position, a pivoted latch for holding the valve member in outlet-opening position but biased to release the valve member, and a tiltable pan for receiving material discharged through the hopper outlet. A pair of mutually attracting magnetic elements respectively carried by the latch and by the pan in spaced relation to each other exert a force that both opposes tilting of the pan and holds the latch in engagement with the valve member after the valve member is moved to outlet-opening position. When the weight of material accumulating on the pan overcomes this force, the pan tips, dispensing the material, and the biased latch is released, allowing the valve member to close the hopper outlet, ending the discharge. A counterweight thereafter returns the pan to its material-receiving position. The weight of material that will tilt the pan may be selected by adjusting the relative spacing of the magnetic elements in a direction perpendicular to the direction in which the element carried by the pan moves when the pan tilts.
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WEIGHING DISPENSER BACKGROUND OF THE INVENTION This invention relates to apparatus for metering and dispensing predetermined quantities of flowable materials. The term flowable materials," as employed herein, is intended to embrace granular, pulverulent, powdered, and other divided or particulate solid materials as well as liquids, slurries, and the like, i.e., materials in general, whether solid or liquid, characterized by an ability to advance in bulk by gravity feed in a substantially continuous and free-flowing manner.
Many types of material-handling operations involve the metering and dispensing of successive discrete quantities of flowable material from a bulk supply thereof. Commonly, in such operations, it is desired that the successive quantities be as nearly identical as possible in weight, each quantity conforming closely to a preselected value of weight. It may also be desirable from time to time, in dispensing successive metered quantities of material from a bulk supply, or in the course of using a given dispensing apparatus, to alter the predetermined weight value so as to increase or decrease the size of the individual dispensed quantities. Other customary desired properties of metering or dispensing apparatus for flowable materials include ease and reliability of operation.
Simply to way of illustration, one specific example of an operation to which the foregoing considerations are pertinent is the dispensing of coffee, i.e., coffee in divided, granular, particulate, or other flowable solid form, such as (by way of example) coffee beans, ground coffee, or powdered coffee. Especially in commercial establishments, it is desirable to dispense, from a bulk supply of coffee, successive carefully metered, substantially equal quantities of coffee. Each of these quantities should conform closely to a preselected weight value, but from time to time it may be desired to adjust that value so as to meter out larger or smaller quantities of coffee. While high repeatability of operation is desired in coffee-dispensing apparatus (i.e., close conformity of each of successive quantities to the predetermined value), coffee dispensing operations are frequently performed by relatively untrained personnel, and it is therefore necessary to provide a dispensing apparatus that can be readily operated by persons having little skill or experience.
SUMMARY OF THE INVENTION An object of the present invention is to provide new and improved apparatus for weighing and dispensing successive quantities of flowable material, characterized by advantageous ease and high accuracy or repeatability of operation.
A further object is to provide such apparatus in which the quantity to be metered can readily be adjusted in a sensitive, accurate manner with minimal danger of disrupted operation owing to misadjustment of the apparatus.
To these and other ends, the present invention broadly contemplates the provision of flowable material metering and dispensing apparatus of the type including a pan for receiving flowable material to be dis-' pensed, means for supporting the pan for movement to and from a material-receiving position in response to absence or presence of weight on the pan, means for retaining the pan in such position with a force that is overcome (releasing the pan for movement) by a preselected weight of material on the pan, and means for dispensing flowable material onto the pan when the pan is in such position, including control means for starting and stopping the discharge of material. In accordance with the present invention, the control means includes a movable control member for stopping discharge, normally urged to a discharge-stopping position but movable to permit discharge, and the retaining means includes first and second mutually attracting magnetic elements respectively carried by the pan and by the control member and cooperating to exert a force that opposes movement of the pan away from its materialreceiving position while simultaneously holding the control member away from its discharge-stopping position. The two magnetic elements are spaced apart by a 7 distance which is at a minimum when the pan is in its material-receiving position and which increases as the pan (carrying one of those elements) moves from such position.
It will be understood that the term mutually attracting magnetic elements is employed herein to designate a pair of elements of such character and disposition that there exists a net attractive force between them. Thus, at least one of the pair of elements is either a permanent magnet or a continuously energized electromagnet; The other element is preferably an armature, but may alternatively be a permanent magnet (or electromagnet) so oriented that opposite poles of the two elements face each other.
In the operation of this device, with the pan in discharge-receiving position, the control means operated to permit discharge of material onto the pan, and the control member held by magnetic force away from its discharge-stopping position, the flowable material to be metered and dispensed is discharged continuously onto the pan. When a sufficient weight of the material has accumulated on the pan, the magnetic force that opposes movement of the pan is overcome, and the pan moves away from its initial position under the weight of material, e.g. tilting to dispense the material through a subjaccnt'funnel or passage. As the pan thus begins to move, the effective air gap between the aforementioned magnetic elements increases, with concomitant very rapid decrease in the force exerted between the elements. Consequently the control member is released for movement to discharge-stopping position, and the discharge of material is arrested. counterweight means or the like may be provided for restoring the pan to its initial material-receiving position for the next cycle of operation.
As a further particular feature of the invention, the magnetic elements may be so arranged that when the pan is in its material-receiving position, the two elements are spaced apart along a line substantially perpendicular to the direction in which the magnetic element carried by the pan moves when the pan begins to descend from the initial position; and at least one of the two magnetic elements may be mounted for positional adjustment along this line. Such adjustment varies the air gap between the magnetic elements when the pan is at the initial position, and hence varies the magnitude of the force then exerted between them. Since the magnitude of the weight of discharged material that will cause the pan to move is dependent on the force opposing such movement, this adjusting feature enables selection of the weight of the dispensed quantities of material. At the same time, the orientation of the direction of adjustment in relation to the direction of movement of the magnetic element carried by the pan facilitates avoidance of undesired contact between the two magnetic elements in the event of misadjustment.
In specific embodiments of the apparatus, the discharge means includes a downwardly opening hopper for containing a bulk supply of flowable material, and the control means includes a valve member biased toward a position closing the hopper outlet but movable to open that outlet. The control means further includes, as the aforementioned control member, a pivoted latch positionable to engage the valve member when the valve is in outlet-opening position, but biased to release the valve for movement to outlet-closing position.
In such embodiment, the pan and a counterweight are carried on a balance beam which is pivotally mounted to move about a horizontal axis intermediate the counterweight and pan. The counterweight opposes downward tipping of the pan from a horizontal position beneath the hopper outlet, but the weight of accumulating material discharged through the outlet onto the pan tends to pivot the beam downwardly, tilting the pan to dispense the material.
The magnetic elements are respectively carried by the latch and pan so as to be in facing, more or less closely spaced relation when the pan is horizontally disposed. One of these elements is mounted for adjustment toward and away from the other. The force exerted between the magnetic elements opposes tilting of the pan either upwardly or downwardly, and also holds the latch in engagement with the valve member for restraining the valve member in the outlet-opening position.
When the valve member is moved to open position (e.g. by means of a handle), material descends from the hopper by gravity onto the pan. The weight of material that will cause the pan to tilt is determined by the force exerted by the magnetic elements. Once this predetermined weight is reached, the pan tilts, the latch is released, the valve member closes the hopper outlet to terminate discharge, and the metered quantity of material is dispensed from the tilted pan. The counterweight then causes the pan to swing back upwardly to its initial, horizontal position where it is held by the magnetic elements for the next cycle. Suitable damping means may be associated with the balance beam for preventing oscillation of the pan especially in its return motion.
Further features and advantages of the invention will be apparent from the detailed description hereinbelow set forth, together with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational sectional view of apparatus for dispensing ground coffee or the like, embodying the present invention in a particular form;
FIG. 2 is a fragmentary view similar to FIG. I, illustrating a first stage in the metering and dispensing operation of the apparatus of FIG. 1;
FIG. 3 is a view similar to FIG. 2 illustrating a subsequent stage in the same cycle of operation;
FIG. 4 is an external side elevational view of the FIG. 1 apparatus, taken along the line 4--4 of FIG. 1;
FIG. 5 is a fragmentary elevational view taken along the line 55 of FIG. 4
FIG. 5a is an enlarged fragmentary detailed view of certain elements shown in FIG. 5;
FIG. 5b is a further enlarged perspective view of an end of the actuating rod shown in FIG. 5;
FIG. 6 is a fragmentary sectional plan view of the apparatus of FIG. 1 taken along the line 6-6 of FIG. 1;
FIG. 7 is a fragmentary plan view taken along the line 77 of FIG. 1;
FIG. 8 is a fragmentary sectional elevational view taken along the line 8-8 of FIG. 1;
FIG. 9 is a side elevational sectional view of a modified form of apparatus, embodying the present invention, for dispensing ground coffee or the like;
FIG. 10 is a fragmentary view similar to FIG. 9, showing an intermediate stage in the metering operation of the apparatus;
FIG. 11 is a fragmentary view taken along the line llll of FIG. 10;
FIG. 12 is an enlarged fragmentary detailed view taken along the line l2-12 of FIG. 10;
FIG. 13 is an enlarged fragmentary detailed view taken along the line l3-l3 of FIG. 10; 9
FIG. 14 is a fragmentary detailed view taken along the line 14-14 of FIG. 10;
FIG. 15 is a sectional plan view taken along the line 1515 of FIG. 9;
FIG. 16 is a view similar to FIG. 10 but showing a further modification of the apparatus to provide demand rather than metered operation; and
FIG. 17 is a fragmentary view similar to FIG. 9, showing another modification in the apparatus of FIG. 9.
DETAILED DESCRIPTION FIGS. 1 8
The present invention is shown in these figures as embodies in apparatus for metering and dispensing successive equal quantities of coffee or like granular or particulate material, in response to successive or repeated displacements of an actuating rod 2.
The apparatus of FIGS. 1 8 is enclosed within a rigid housing 10 divided into upper and lower chambers (respectively designated 11 and 12) by a downwardly tapering frustoconical wall 14. At its lower end, the wall 14 defines a circular discharge opening or outlet 15. The chamber 11, enclosed by wall 14 and the upper portions of the housing 10, thus constitutes a hopper for containing a bulk supply 16 of flowable solid material such as coffee. The top of the hopper may be closed by a removable lid 17.
The outlet 15 is normally closed by a manually operable valve comprising a guillotine member 20 disposed below the wall I4 for movement in a curved path about a horizontal axis, into and out of engagement with the downwardly projecting circular lip 15a of the outlet 15. As shown, the guillotine member is a rigid plate, curved on the same radius as its path of movement, and dimensioned to close the outlet 15 completely when in its lower position. The lip 15a, engaging the upper surface of member 20, may be formed with a knife edge to prevent clogging.
As best seen in FIGS. 7 and 8, the guillotine member 20 includes a pair of laterally and upwardly projecting arms 22 which are pivotally secured to side wall portions of the housing 10 (externally of wall 14) so as to support the guillotine for movement along the aforementioned curved path. One of the arms 22 is connected to a resiliently flexible lever such as a trip wire 23 that projects outside the housing for angular movement in a plane generally parallel to the adjacent housing wall, between lower and upper limiting positions respectively defined by stop pins 23a and 23b (FIGS. 5 and 5a) mounted in the housing wall to engage and arrest the trip wire. As hereinafter further explained, this trip wire 23 is movable by the actuating rod 2 (from lower to upper position) to effect movement of the guillotine 20 from closed to open position.
As seen in outlet-closing position (FIGS. 1 and 3), the guillotine extends beneath the outlet and further includes an elongated portion 24 extending upwardly therefrom along the same curved path, beneath the wall 14. In such closed position, the leading edge of the guillotine member abuts a small resilient bumper 26 fixedly mounted on a short wall portion 27 of the housing structure adjacent the outlet 15. When the guillotine is swung upwardly (by means of trip wire 23) to the open position shown in FIG. 2, its trailing edge may abut a similar bumper 28 mounted at the junction of wall 14 with housing 10. As thus displaced to open position, the guillotine 20 clears the outlet 15, permitting the material 16 to flow freely through the outlet from the hopper 11, under the force of gravity.
The extension 24 of the guillotine member, together with the illustrated disposition of the pivotal mounting for the guillotine member, causes the member to be gravity-biased toward its closed position; i.e., if the member 20 is moved to the open position shown in FIG. 2 and released, it returns immediately by gravity to the closed position of FIGS. 1 and 3. The weight of extension 24 is selected, in relation to the nature of the material being dispensed, to insure that return movement of the guillotine member to outlet-closing position will be effected sufficiently forcefully to overcome the resistance of the material flowing downwardly through outlet 15.
In order to retain the guillotine member in the outletopening position, a sear or latch member 30 is pivotally secured to fixed wall portions 31 of the housing structure by a pivot shaft 32 (FIG. 7) for angular displacement about a horizontal axis, below the curved path of the guillotine member. It will be understood that for convenience of expression, the terms pivot and pivotally are used herein to refer to angular displacement about a fixed axis, and to designate mountings (of apparatus elements) permitting such motion, whether the mountings are pivots in a conventional sense or are other structures such as rotatable shafts or fixed shafts on which elements are journalled for such motion. The latch 30 includes a short transverse arm 311a which extends inwardly (toward outlet 15) from pivot 32 and terminates in an upwardly projecting tooth 30b disposed for insertion in a detent opening 34 in the guillotine member, i.e., when that member is swung to open position (FIG. 2), to engage and hold the guillotine member against return movement to outlet-closing position. Latch 30 also includes a further arm 300 formed integrally with and extending downwardly from the arm 30a between spaced stop pins 37 and 38 which are mounted in the wall portions 31 to limit the angular travel of the latch.
A balance beam 40, disposed in downwardly spaced relation to the hopper wall 14, is mounted for movement about a horizontal axis by means of a pivot shaft 41 journalled in inwardly projecting portions 42 of the housing wall structure. The beam includes a scale arm 40a carrying a shallow tray or pan 44 and a counterweight arm 40b respectively disposed on opposite sides of shaft 41 so that when the beam is in the horizontal position shown in FIGS. 1 and 2, the pan 44 is located directly beneath and aligned with the hopper outlet 15 for receiving material discharged through the outlet. The counterweight arm 40b overbalances the arm 40a and the empty pan 44 slightly so as to restore the beam toward the horizontal after an angular displacement of the beam clockwise from the position shown in FIG. 1. Magnetic elements 57 and 58 are then effective to hold the beam 40 horizontal, as explained more fully below.
When the material 16 is delivered to the pan 44, the weight of that material tends to cause clockwise pivotal motion of the beam (overbalancing the counterweight), tilting the pan downwardly so that the material falls therefrom into the lower portion of the housing 10, as shown in FIG. 3. This lower housing portion may, as shown, be formed to constitute a downwardly tapering funnel 46 for dispensing the falling material through a passage 47 at the lower extremity of the apparatus.
The counterweight arm 40b is shown as wedgeshaped with a curved or arcuate outer periphery 49 (of uniform radius) concentric with pivot 41, and carries an arcuate retaining member 50 having a major extent conforming in curvature with but spaced outwardly from the periphery 49. The arm 40b is of relatively light material, e.g. plastic, and the retaining member 50 is of relatively heavy material, e.g. steel, so that the member 50 constitutes the principal counterweight. The member 50 has its ends bent in the form of spring fingers 500, which engage recesses in the arm 40b, so that the member 50 may be readily removed and replaced by a lighter or heavier member, as required by the quantity to be dispensed by the apparatus. Periphery 49 and retaining member 50 cooperatively define a curved track (having closed ends) within which may be disposed a roller 52, joumalled (for rotation about a horizontal axis) at the end of the crank arm on a crankshaft 53 (FIG. 6) that is pivotally mounted on the housing structure, and frictionally engaging the periphery 49 of arm 40b so that the roller rotates aobut a horizontal axis. A pair of governor blades 54 are connected to the roller 52 for rotation therewith. The roller 52 and blades 54 rotate as the beam is restored to horizontal position by the action of counterweight air resistance to rotation of the blades, transmitted to the beam by the frictional engagement of the roller 52 therewith, serves a damping function that prevents undesired overtravel and oscillation of the beam such as might otherwise occur during its return to horizontal position.
The horizontal axis 53a about which the crankshaft 53 rotates is spaced from the pivot shaft 41 of the balance beam 40 by a distance which is less than the sum of the radius of the periphery 49 and the length of the crank arm of crankshaft 53, at the end of which arm the roller 52 is journalled. Furthermore, the roller 52 is above the line between the axis 53a, and the pivot shaft 41 (i.e., the axis of roller 52 lies above the plane defined by the horizontal axes of beam pivot shaft 41 and crankshaft 53). Because of this dimensional relationship, when the balance beam 40 moves clockwise from the position of FIG. 2 to the position of FIG. 3, the frictional engagement between periphery 49 and roller 52 lifts the crank arm upward, decreasing that frictional engagement, so that the roller 52 slides in the space provided betweem member 50 and periphery 49, and rotates very little, if at all, with a minimal retarding effeet on the motion of the balance beam 40.
On the other hand, when the balance beam moves counterclockwise from the position of FIG. 3 to that of FIG. 2, the frictional engagement of periphery A9 and roller 52 tends to move the cranksahft 53 clockwise on its pivot, thereby forcing the roller 52 more tightly against periphery 49 and rotating the blades 54 to produce a maximum damping action on the motion of balance beam 40.
As a particular feature of the invention, for metering and dispensing flowable solid material, the pan 44 has a downwardly tapering conical shape with side walls sloping at an angle of between about 3 and about 10 to the horizontal when the beam 40 is in its horizontal position. This slope of the pan surface is advantageous for optimum dumping of accumulated material from the pan when the pan is tilted downwardly, and for optimum piling of the material, without spillage, when the pan is filling.
In accordance with the invention, a pair of magnetic elements 57 and 58 are respectively carried by the latch 30 and the beam 41th in facing relation to each other. The latch arm 300 extends downwardly to the level at which scale arm 40a is located when the beam 40 is in horizontal position so as to be in horizontally spaced relation to the extremity of the scale arm 50a. Magnetic element 57 is secured to a screw 60 which is threadedly mounted in the lower extremity of the latch arm 306 (with element 57 facing toward the beam), while magnetic element 58 is mounted in the beam end facing element 5'7. The disposition of these elements is such that, when the beam is in its horizontal position (FIG. ll), the elements 57 and 558 face each other across a small air gap 62. The dimension of this air gap may be adjusted by turning the screw 6th so as to move element 5'7 toward or away from element 58, but the adjustment is limited, eg by deforming a thread on the screw 6th, so that the air gap is maintained at all times.
As shown, element 57 is a magnet, while element 58 is an armature on which 57 exerts an attractive force which is a maximum when the air gap is shortest, i.e., when the pan 44 is in the horizontal position. While element 57 may be a continously energized electromagnet, it is presently preferred (for the sake of convenience and simplicity) that element 57 be a permanent magnet. Alternatively, the elements 57 and 58 may be reverse, so that 57 is an armature and 58 a magnet, or both elements may be magnets with facing poles of opposite polarities.
As will now be understood, the force exerted by magnet 57 on armature 58, when the beam 4% is in its horizontal position shown in FIG. ll, holds the beam horizontal. When the pan is empty, the counterweight arm 40b and counterweight 50 overbalance the scale arm 40a slightly, and this overbalance is counteracted by the magnetic elements 57 and 58. As the pan 44 starts to till, the balance beam becomes overbalanced in the opposite direction, and the magnetic elements 57 and 58 are then effective to hold the beam horizontal until the weight of material on the pan exceeds a predetermined value, dependnet on the strength of the magnetic elements 57 and 58 and the length of the air gap between them. At the same time, this force of elements 57 and 58 also urges the pivoted latch 30 in a clockwise direction as seen in FIG. il, i.e., toward the inner stop pin 37. As will be apparent from FIG. 2, when the latch 30 is at the limit of its clockwise pivotal movement (engaging pin 37), the latch tooth 30b is in a position to be received within the detent opening 34 of the guillotine member 20 and thus to hold the guillotine member in the above-described outlet-opening position. The latch 30 is so balanced on its pivot shaft that (in the absence of the described magnetic force) it is urged by gravity in a counterclockwise direction from the position shown in FIG. 1, to an outer limiting position in which it engages pin 38; when the latch is disposed at this outer limiting position, tooth 30b is located beneath (and clear of) the path of guillotine movement. The guillotine extension 24 may bear, on its upper surface, a wear plate 24a removably secured to the guillotine as by screws 24b and having a lip extending over the rim of opening 34 that is engaged by tooth 30b, for protecting that rim.
As shown in FIG. 4, the dispensing passage 47 projects downwardly below the bottom of the housing 10 so as to be receivable within a manually held coffee cup K or the like. The rod 2 has its lower end received, for guided vertical movement, within a vertical slot 47a formed in the wall of passage 47. From slot 47a, a horizontal arm portion 2a of rod 2 extends below the housing 10 to a locality beneath the position of trip wire 23 adjacent a vertical wall of the housing; at that point, the rod is bent upwardly, forming a vertical leg 2b that projects upwardly through a vertical guide sleeve 10a provided on the outer surface of the last-mentioned housing wall beneath the trip wire 23. Above sleeve 10a, the rod is bent again to form a further horizontal arm 20 (FIG. 5) that extends in parallel relation to the adjacent housing wall and terminates in a short, upwardly projecting vertical leg 2d having a transversely projecting upper end 2e (FIG. 5b) positioned to engage the free end of the trip wire 23. Rod 2 is movable vertically between the lower position shown in FIGS. 4 and 5, at which the upper rod end 2e is disposed immediately below the free end of trip wire 23 (i.e., when the trip wire is at its lower position, engaging stop pin 23a), and an upper position at which the upper rod end 2e reaches the position shown at 2e (FlG. 5a).
The described vertical movement of rod 2 is effected by manually moving a cup K (FIG. upwardly over passage 47 so that the cup lip engages, and pushes upwardly, the horizontal arm 2a of the rod. As the rod begins to rise, its upper end 2e engages and pushes upwardly against the trip wire 23, causing the trip wire to pivot upwardly from its lower position (engaging pin 23a) to its upper position, at which the trip wire is arrested by pin 23a. This upward movement of the trip wire swings the guillotine 20 from outlet-closing position to outlet-opening position, as described above.
The upper most position 2e of rod end 2e is, as indicated in FIG. 5a, slightly above the position at which the trip wire 23 comes into engagement with the upper stop pin 23b. As shown in FIG. 5b, rod end 2e is cut away to provide a half-round configuration with a flat side facing the trip wire 23. This shape of end 2e permits the free end of the trip wire to be released from engagement with rod end 2e as the rod end continues to move upwardly (to position 2e) after the trip wire has engaged pin 231;. In other words, during the terminal stage of upward movement of rod end 22, the free end of the resilient trip were 23 flexes progressively, until (as permitted by the cutaway configuration of end 2e) it is released, and springs downwardly away from end 2e, which is now positioned above the trip wire. Consequently the trip wire and guillotine are free to fall to outlet-closing position upon release of latch 30, without interference with rod end 2e, even though cup K is still held in a position that maintains rod end 2e at the upper position 2e. When the cup is thereafter removed, the arm 2 drops, with sufficient force so that (again owing to the resiliency of trip wire 23, and the cutaway configuration of the rod end 2e), the end 2e descends past the free end of the trip wire to its initial position beneath the trip wire.
Means for retarding upward movement of rod 2 are also provided in the apparatus of FIGS. 1 8, to prevent metering errors that might otherwise result if a cup K were moved rapidly upwardly and downwardly, moving the guillotine to outlet-opening position and then releasing it before the latch 34) could move to hold the guillotine in that open position. This retarding means is illustrated in FIG. 4 as comprising a dashpot 65 including a downwardly opening, axially vertical cylinder 66 formed in the lower portion of the housing an upwardly opening cup-shaped piston 67 disposed for axial movement in cylinder an and connected to rod arm 2a by a lug 67a; and a vaned valve member 68, loosely contained within piston 67 and seating in an aperture 68a in the bottom of the piston. When the rod 2 is pushed upwardly, piston 67 is forced upwardly into cylinder 66 while valve 63 closes aperture 68a, so that air in the cylinder is compressed, resisting (and hence retarding) the upwared movement of the rod sufficiently to permit latch 30 to catch and hold the guillotine member in open position. Upon release of the rod, the piston 67 is free to fall, and any negative pressure differential between the cylinder and ambient atmosphere (such as might tend to retard downward movement of the piston) is relieved by movement of valve 68 relative to the piston, opening aperture 68a.
The foregoing arrangement of rod 2, trip wire 23, and dashpot 65, as will now be seen, is designed to enable the apparatus to provide accurate metering operation despite variations in manual actuation, i.e., regardless of whether the cup K is held in an upper position or moved rapidly up and down. Accordingly, the described apparatus affords desirable freedom from human error, an advantage which is especially important for operations (such as coffee dispensing) commonly performed by relatively unskilled personnel.
The operation of the described apparatus may now be readily explained. A supply lid of bulk tlowable solid material such as coffee is initially charged to the hopper ill with the lid 17 removed. A receptacle such as cup K for receiving a metered quantity of the material is placed beneath the downwardly opening dispensing passage 47. At this time, the beam 40 is in the horizontal position shown in FIG. ll, held by the force of magnet 57 exerted on armature 53. The guillotine member is in the closed position, preventing discharge of material from hopper 11 through outiet 15. The latch 30 is urged clockwise as seen in H6. 1, by the aforementioned magnetic force, but is arrested short of its clock wise limit of travel by engagement of the tooth 30b with the lower surface of the guillotine extension 24.
To dispense a metered quantity of the material into the receptacle, cup K is raised, moving rod 2 (and hence trip wire 23) upwardly to swing the guillotine to open position. As the guillotine detent opening 34 comes into register with the latch tooth 30b, the force exerted by magnet 57 on armature 58 pivots the latch clockwise so that the tooth 30b is received in the detent opening 34, holding the guillotine member in its outletopening position, and allowing magnet 57 to swing slightly closer to armature 58.
With the outlet thus open, as seen in FIG. 2, granular material is discharged freely therethrough onto the pan 44. The combined forces of counterweight arm 40b, counterweight 50 and magnetic elements 57 and 58 retain the beam 40 in horizontal position, despite the growing weight of material on the pan. However, when a sufficient weight of material has accumulated on the pan to overcome the combined effect of the counterweight and magnetic forces, the pan 44 begins to tilt, i.e., the beam 40 begins to pivot in clockwise direction as seen in FIG. 3.
The clockwise pivotal motion of the beam carries the armature 58 progressively further away from the magnet 57. As the space between magnet and armature thus increases, the force exerted by the magnet on the armature decreases in accordance with the inverse square law, producing rapid acceleration of beam pivotal movement, and concomitantly releasing the latch 30 for counterclockwise pivotal movement by gravity into engagement with pin 38. This movement of the released latch carries the tooth 30b downwardly out of engagement with the guillotine, freeing the guillotine to drop back to outlet-closing position, and thereby to stop the discharge of material through outlet 15. In other words, as the pan tilts downwardly, the discharge of material is stopped. The continuing downward tilting of the pan dumps the accumulated material into the funnel 46, whence it falls through passage 47 into the aforementioned receptacle. It should be noted that FIG. 3 illustrates the extreme downward limit of tilting movement of the pan; ordinarily the pan does not travel so far, but instead the accumulated material falls from the pan when the pan has moved thorugh a somewhat lesser angle from the horizontal, i.e., when the pan is at a position displaced counterclockwise from that shown in FIG. 3.
Once the accumulated material has fallen from the pan, the beam is restored to its initial horizontal position by the counterweight ann 40b and magnetic elements 57 and 58; i.e., the counterweight causes the beam to swing in a counterclockwise direction (as viewed in FIGS. 1 3), and the attractive force between elements 57 and 58 arrests this counterclockwise movement as the pan reaches its initial, horizontal position. At the same time, the attraction between elements 57 and 58 swings the latch back into a position for engaging detent opening 34 of guillotine 20 when the guillotine valve is re-opened. As sonn as a new cup K is placed beneath passage 47, a further metered quantity of the material 16 can be dispensed by the apparatus in the same manner as described above.
Since the magnetic component of the force that acts on beam 40 to retain the pan in horizontal position is related to the distance between magnet 57 and annature 58 when the beam is horizontally disposed, the magnet-armature spacing determines (for any constant weight of the counterweight member 50) the weight of material which will overcome the panretaining force and cause tilting of the pan and closure of the outlet 15 by guillotine 20.. In other words, the spacing between magnet 57 and armature d predetermines the weight of each individual metered quantity of material dispensed by the apparatus. It is found that for a given relative spacing of the magnetic elements 57 and 58, the operation of the illustrated apparatus is highly repeatable; i.e., successive metered and disposed quantities of material are highly uniform in weight.
To change the weight of such metered quantity, the magnet-armature spacing may be adjusted by turning the threaded mounting of magnet 57 in latch arm 30c. Once that spacing is adjusted, the apparatus will dispense metered quantities of material having a new (larger or smaller) value as desired. To facilitate adjustment of magnet position, the outer end of post 60 may be slotted, and may be accessible (for turning, as by means of a screwdriver) through an opening 64 in the adjacent wall of the housing Ml When the loaded pan begins to tilt, the outlet is not instantly closed, but instead remains open (with continuing discharge of material therethrough) during the short interval required for the guillotine to fall back to outlet-closing position. The total weight of material in each metered quantity dispensed by the apparatus is thus the sum of the weight that is deposited on the pan before the pan begins to tilt, and the weight of the increment of material discharged through the outlet 15 between the time when the pan begins to tilt and the time when the guillotine fully closes the outlet. As stated, the weight of material required to tilt the pan is determined by the attractive force between elements 57 and 58. The rate of closing of the guillotine depends on the size of the granules or particles flowing through the outlet, being slower when the particles are large than when they are small; it is found that for a given particle size range and density, the weight of the increment of material discharged through the outlet during the guillotine-closing period is substantially constant, and hence does not adversely affect the metering accuracy or weight-selecting adjustability of the apparatus.
It will be noted that when the beam is horizontally disposed and the outlet H5 opened, the spacing between the magnet and armature is at a minimum, and these elements are then spaced along a horizontal line, i.e., a line perpendicular to the (vertically downward) direction of initial movement of the armature when the pan begins to tilt; the armature follows an arcuate path, but the instantaneous direction of its motion from the horizontal is, of course, tangent to that path. The adjustment of the air gap 62 is effected by movement of the magnet 57 along this horizontal line, i.e., in a direction perpendicular to the direction of armature motion. Owing to this relative orientation of the direction of magnet adjustment and the direction of armature motion, the adjusting mechanism can readily be constructed so as to prevent adjustment of the magnet into a position at which the magnet contacts the armature, which would be highly undesirable.
FIGS. 9 115 This embodiment includes a housing 70 having an upper portion shaped to constitute a hopper 72 for bulk solid flowable material, with a hinged lid '73 for the hopper. The metered material is dicharged from the hopper by gravity through a downwardly opening outlet 74 onto a. shallow pan 75 which may have the same surface configuration as the pan 44 of the FIG. 1 apparatus. A beam 77, pivotally mounted at 78 on portions of the housing structure for angular displacement about a horizontal axis, carries the pan and a bifurcate counterweight structure 80 on opposite sides of its axis of pivotal movement. The counterweight structure 80 includes a pair of arms 80a on which are threaded weights 80b, and is arranged to maintain the pan in a horizontal position directly beneath and aligned with hopper outlet 74, and to restore the pan to such position when the pan is tilted downwardly by weight of material delivered thereto from the hopper. A spring element 81, fixedly mounted in relation to the beam, has free lower end portions 81a positioned to engage the counterweight assembly 80 in the event of counterclockwise overtravel of the beam, for inhibiting oscillation of the beam as the pan is restored to horizontal position.
Discharge of material through the hopper outlet is controlled by a valve member 82 which comprises a horizontal slide, i.e., a flat rigid plate supported between upper and lower rollers 84 for horizontal movement between a position (shown in FIG. 9) at which the slide completely closes outlet 74, and a position (shown in FIG. 10) at which an aperture 86 in slide 82 is in register with outlet 74. A pair of biasing springs 88, under tension between the slide and a wall portion of the housing, urge the slide toward its outlet-closing position (the left-hand limit of its path of travel, as seen in FIG. 9). When the slide is moved to the outlet-opening position, at which aperture 86 is in register with outlet 74 so that material from the hopper can fall freely through the outlet and aperture, the slide is at the righthand limit of its path of travel as seen in FIG. 10.
A latch 90, mounted on portions of the housing structure by a pivot shaft 91 for pivotal motion about a horizontal axis, is provided for holding the slide 82 in open position against the biasing force of spring 88. Latch carries, on a short transverse arm 90a, an upwardly projecting tooth 90b arranged for insertion within a detent opening 94 of slide 82, i.e., when the slide is in open position. The latch 90, which is generally similar in structure and function to the latch 30 of the FIG. 1 apparatus, also includes a downwardly extending arm 99c.
Also as in the apparatus of FIGS. ll 8, the latch arm 90c and the adjacent extremity of beam 77 (carrying pan 75) respectively bear two mutually attracting magnetic elements 97 and 98. One of these elements (e.g. element 97) is a permanent magnet or a continuously energized electromagnet, while the other (e.g. element 98) may be a magnet or an armature; as shown, both elements 97 and 98 are permanent magnets, oriented so that their respective facing poles are of unlike polarity. The dispostion of the two magnetic elements is such that when the pan 75 is in the horizontal, materialreceiving position shown in FIG. 9, elements 97 and 98 are disposed in horizontally spaced, facing relation with a small air gap 99 between them. The attractive force then exerted between magnets 97 and 98 opposes movement of the pan away from horizontal position.
The same magnetic force simultaneously urges the pivoted latch 90 in a clockwise direction in FIG. 9, thus urging the latch tooth 90b upwardly for insertion in the detent opening 94 of slide 82. Clockwise movement of latch 90 is limited by engagement of the latch arm 90a with the lower surface of the slide 82. Again as in the case of the latch 30 in the FIG. 1 apparatus, latch 90 is so balanced on its pivotal mounting that it is normally urged by gravity in a counterclockwise direction that carries the tooth 90b downwardly out of engagement with slide 82. counterclockwise movement of the latch is limited by a stop screw 90d adjustably secured to a portion of the housing structure.
The magnitude of the force exerted between magnets 97 and 98 is determined by the size of the air gap 99. To permit adjustment of the size of this air gap, one or both magnets 97 and 98 are threadedly mounted so as to be horizontally adjustably in position.
The left-hand end portion of slide 82 (as seen in FIG. 9) is bent downwardly and then upwardly to form a stop flange 100 that abuts an internal wall portion 101 of the housing structure to limit the leftward travel of slide 82. I-Iingedly mounted on the under side of the left-hand end portion of slide 82 is a cam follower frame 103 lightly biased by a spring 104 into engagement with the under side of the stop flange portion 100 of the slide. In that position, the frame 103 slopes leftwardly and downwardly from the horizontal path of slide 82, but the hinged connection betweenframe 103 and slide 82 permits downward (counterclockwise) pivotal movement of the frame e.g. to the position indicated by dotted lines at 103 in FIG. 9.
At its leftward extremity, the frame 103 bears a cam follower roller 105 adapted to ride on and cooperate with a cam portion 107 of a vertically extending actuator rod 108 supported for vertical displacement in the left-hand side of the housing structure 70 as seen in FIG. 9. Rod 108 terminates at its lower extremity in a horizontal arm 110 positioned to be engaged and lifted by the lip of a receptacle such as a coffee cup (not shown). In its initial position, the rod 108 has the position shown in FIG. 9, with the knee-shaped cam portion 107 disposed beneath cam follower 105. The slide 82 is then at its leftward limit of travel. Whem arm 110 is manually lifted, however, earn follower 105 rides on the cam portion 107 of the actuator rod 108, over the peak of portion 107, forcing the slide 82 horizontally to the right against the springs 88, until the actuator rod 108 reaches an upper limiting position as shown in FIG. 10. The slide 82 has now moved to the outlet-opening position of FIG. 10, where it is held by the insertion of latch tooth 90b in the detent opening 94; and the projection of actuator cam portion 107 has passed above cam follower 105. Accordingly, if the slide is released by the latch while the rod 108 is maintained in this upper position (i.e., while rod am 110 continues to be supported by a coffee cup held beneath it), the cam portion 107 does not interfere with leftward, outletclosing movement of the slide, since the cam follower 105 rides along the downwardly and leftwardly sloping lower reach of cam portion 107, pivoting counterclockwise (relative to the slide) if necessary. Subsequent descent of rod 108 to its initial, lower position is similarly accommodated by counterclockwise pivotal movement of the cam follower 105, without disturbing the outletclosing position of the slide. Thus the metering opera tion of the apparatus is performed independently of the position of rod 108, once that operation has been initiated by upward movement of the rod.
The upward motion of the actuator rod 108 may also operate a tamping or agitating element 114 located within the hopper and bearing horizontal discs 115 for promoting uniform downward flow of material from the hopper through outlet 74. As shown in FIG. 9, the upper end of the actuator rod 108 may engage a pivoted arm 110 (as rod 108 moves to the top of its path of travel), the tamping device being secured to and moved by arm 116.
With the hopper 72 filled with bulk flowable solid (e.g. granular or particulate) material, dispensing of a metered quantity of such material in the apparatus of FIG. 9 is initiated by lifting of the arm 110. The slide 82 is advanced to the right and latched in outletopening position as shown in FIG. 10, permitting material from the hopper to flow through outlet 74 onto the horizontally positioned pan 75. Upon delivery to the pan of a sufficient weight of material to overcome the combined force of the counterweight structure and the magnetic elements 97 and 98, the pan tilts downwardly; at the same time, the rapid diminution of magnetic force releases latch to swing in a counterclockwise direction, freeing slide 82 for leftward outletclosing movement under the force of spring 88. Thus the delivery of a predetermined weight of material to the pan 75 both tilts the pan and closes the hopper outlet. The metered quantity of material (i.e., the weight that causes the pan to tilt plus the weight of the increment of material discharged between the time the pan starts tilting and the time outlet 74 closes) falls onto a sloping lower portion 120 of the housing 70 which guides the material to a dispensing passage 122 beneath which there may be positioned a receptacle (not shown) for receiving this metered quantity of material. Passage 122 projects downwardly from the housing and is dimensioned to be received within a coffee cup or the like, while the arm 110 of actuator rod 108 extends through a vertical slot 122a in the wall of this passage, so that positioning of a cup in material-receiving relation to the passage lifts the arm 110 to initiate the metering and dispensing operation of the apparatus as described above.
Restoration of the pan to its horizontal position by the counterweight structure 80 readies the apparatus for repetition of the operation to dispense another such metered quantity of material. As in the case of the FIG. 1 apparatus, the predetermined weight of each metered quantity of material is related to the spacing between the magnetic elements 97 and 98 and may be varied by adjustment of that spacing, or by changing the size of the counterweights 80b.
FIG. 10 illustrates a modification that may be made in the apparatus of FIGS. 9 15 to provide demand rather than metered dispensing. That is to say, with the structure of FIG. 16, the amount or" material dispensed in each cycle is controlled manually by the operator rather than being predetermined.
Specifically, in FIG. 16, in place of the actuator rod 108 with its cam portion 107, there is provided an actuator rod 108' having a cam portion 107' which juts out further to the right (as seen in the figure) than does the cam portion 107. As illustrated in FIG. 16, when rod 108' is moved manually upward to the upper limit of its travel, the cam portion 107' still engages the cam follower in such manner that the slide 82 is positively held in outlet-opening position regardless of the position of latch 90. Thus discharge of material continues as long as the rod 108' is supported manually in an upper position, i.e., until the. rod is released for downward movement.
The apparatus is generally similar to that of H08. 9 15 except that the centrally pivoted arm M6 that holds agitating element 114 is replaced by an arm H6 pivoted at its end in the wall of the housing opposite rod 108, so that the agitating element is carried by rod 116' between its pivotal mounting and rod 108..
In the structure of H6. 9, upward movement of rod 108 into engagement with arm 136 causes downward movement of element 1114, so that the discs 115 tamp the supply of material in hopper 72. Owing to the disposition of element H4 between rod Mp8 and the piv otal mounting of arm lilo in the structure of FIG. 17, however, upward movement of rod 108 into engagement with arm 116' produces upward motion of the element 114 so that the discs lift or fluff the material in the hopper. The selection of the agitating arrangement to be employed is dependent on the properties of the material being dispensed.
It is to be understood that the invention is not limited to the features and embodiments hereinabove specfically set forth but may be carried out in other ways without departure from its spirit.
1. .ln dispensing apparatus, the combination of a. a pan for receiving material to be dispensed;
b. means for supporting the pan for movement to and from a material-receiving position in response to absence or presence of weight on the pan; and
c. means for retaining said pan in said position with a force that is overcome, releasing said pan for movement, by a preselected weight of material on the pan;
wherein the improvement comprises d. said retaining means including first and second mutually attracting magnetic elements respectively carried by said pan for movement therewith and connected to said supporting means, said elements being spaced apart, when said pan is in said position, along a line substantially perpendicular to the direction of motion of said first element such that said elements exert on each other an attractive force opposing movement of said pan from said position; and
e. means, mounting at least one of said elements for positional adjustment toward and away from the other along said line, for varying the distance between said elements, thereby to vary the magnitude of said last-mentioned force.
2. ln dispensing apparatus, the combination of a. a pan for receiving flowable material to be dispensed;
b. means for supporting the pan for movement to and from a material-receiving position in response to absence or presence of weight on the pan;
c. means for retaining said pan in said position with a force that is overcome, releasing said pan for movement, by a preselected weight of material on the pan; and
d. means for discharging flowable material onto said pan when said pan is in said position, including control means for starting and stopping discharge of material;
wherein the improvement comprises e. said control means including a movable control member normally urged to aposition for stoppingdischarge but movable away from discharge stopping position for permitting discharge; and
f. said retaining means including first and second mutually attracting magnetic elements respectively carried by said pan and by said control member, said elements being spaced apart by a distance which is at a finite minimum value when said pan is in said material-receiving position and said elements then exerting on each other a predetermined attractive force simultaneously opposing movement of said pan and holding said control member away from said discharge-stopping position, said predetermined force being overcome by said predetermined weight of material on said pan such that said pan moves from said material-receiving position, increasing the distance between said elements and thereby decreasing the attractive force between said elements so as to release said control member for movement to said discharge-stopping position.
3. Apparatus as defined in claim 2, wherein said magnetic elements are spaced apart, when said pan is in said material-receiving position, along a line substantially perpendicular to the direction of motion of said first element; and further including means, mounting at least one of said elements for positional adjustment toward and away from the other along said line, for varying the distance between said elements, thereby to vary the magnitude of the attractive force between said elements.
4. ln dispensing apparatus, the combination of a. a container having a downwardly opening outlet for discharging flowable material;
b. a valve member for closing said outlet biased to outlet-closing position but displaceable to a position at which said outlet is open;
0. a pivoted latch for engaging and holding said valve member in outlet-opening position, biased away from engagement with said valve member;
(1. a pan for receiving flowable material discharged through said outlet, pivotally movable upwardly to and downwardly from a material-receiving position beneath said outlet in response to absence and presence of weight on the pan; and
e. means for retaining said pan and latch in positions for discharge of material through said outlet onto said pan, said retaining means holding said pan in said position with a force that is overcome, releasing said pan for movement, by a preselected weight of material on the pan, said retaining means including first and second mutually attracting magnetic elements respectively carried by said pan and by said latch, said elements being spaced apart by a distance which is at a finite minimum value when said pan is in said material-receiving position and said elements then exerting on each other a predetermined attractive force simultaneously opposing movement of said pan and holding said latch in position for engaging said valve member, said predetermined force being overcome by said predetermined weight of material on said pan such that said pan moves from said material-receiving position, increasing the distance between said elements and thereby decreasing the attractive force between said elements so as to release said latch for movement away from engagement with said valve memher.
5. Apparatus as defined in claim 4, further including i. pivotal mounting means for said pan comprising a beam mounted for pivotal movement on a horizontal axis and carrying said pan, and
ii. a counterweight carried by said beam for opposing downward movement of said pan away from said material receiving position.
6. Apparatus as defined in claim for dispensing flowable solid material, wherein the inner surface of said pan is of conical configuration sloping downwardly at an angle of between about 3 and about to the horizontal when said pan is in material-receiving position, said pan tilting downwardly, for dumping material received therein, when moved from material-receiving position by weight on said pan.
7. Apparatus as defined in claim 5, wherein said beam includes a portion, on the side of said axis opposite to said pan, having an outer periphery of arcuate configuration concentric with the axis of beam movement, and further including i. a roller frictionally engaging said arcuate periphery for rotation in response to pivotal movement of said beam, and
ii. means for exerting a damping force on said roller to oppose oscillation of said beam incident to pivotal movement of said beam.
8. Apparatus as defined in claim 7, further including means, mounting said roller, for causing said roller to bear with. greater force against said arcuate periphery during upward movement of said pan than during downward movement of said pan.
9. Apparatus as defined in claim 8, wherein said roller-mounting means comprises a crankshaft pivotally movable about a horizontal axis and supporting said roller for rotation about a horizontal axis spaced from said crankshaft axis, said crankshaft axis and said beam axis being spaced apart in a common plane at a distance greater than the radius of said arcuate periphery but less than the sum of said radius and the distance between said crankshaft axis and said roller axis, said roller axis lying above said common plane.
10. Apparatus as defined in claim 7, wherein said damping means comprises at least one blade carried by said roller for rotation therewith and so shaped that air resistance to rotation of said blade exerts a damping force on said roller.
11. Apparatus as defined in claim 5, wherein said latch is biased by gravity away from engagement with said valve member, and wherein said valve member is pivotally mounted and is biased by gravity to outletclosing position.
12. Apparatus as defined in claim 5, wherein said latch is biased by gravity away from said valve member, wherein said valve member is mounted for sliding movement between outlet-opening and outlet-closing positions; and further including i. means for resiliently biasing said valve member toward outlet-closing position;
ii. a cam follower carried by said valve member; and
iii. cam means including a manually operable handle for engaging said cam follower, upon movement of said handle, to move said valve member to outletopening position.
13. Apparatus according to claim 4, wherein said magnetic elements are so disposed as to be spaced apart, when said pan is in said material-receiving position, along a line substantially perpendicular to the direction of motion, and further including means, mounting at least one of said elements for positional adjustment toward and away from the other along said line, for varying the distance between said elements, thereby to vary the magnitude of the attractive force between said elements.
14. Apparatus according to claim 13, wherein said element-mounting means comprises means for threadedly mounting one of said magnetic elements on said latch.
15. Apparatus as defined in claim 6, wherein said angle is about 5.
16. In apparatus for dispensing flowable material, the combination of a. a pan for receiving said material;
b. a beam mounted forpivotal movement on a horizontal axis and carrying said pan for pivotal movement upwardly to and downwardly from a horizontal material-receiving position in response to absence and presence of material on said pan; and
c. a counterweight carried by said beam for opposing downward movement of said pan from said horizontal position;
wherein the improvement comprises:
d. said beam including a portion having an arcuate periphery concentric with said beam axis, disposed on the side of said beam axis opposite to said pan;
e. a roller frictionally engaging said arcuate periphery for rotation in response to pivotal movement of said beam;
f. means, mounting said roller, for causing said roller to bear with greater force against said arcuate periphery during upward movement of said pan than during downward movement of said pan; and
g. means for exerting a damping force on said roller to oppose oscillation of said beam incident to pivotal movement of said beam.
17. In apparatus for inhibiting oscillation incident to pivotal movement, the combination of a. a member pivotally movable in either of two opposite directions about a first axis;
b. said member including a portion having an arcuate periphery of given radius concentric with said first axis;
. a roller engaging said arcuate periphery for rotation in correspondence with movement of said member;
a crankshaft mounted for pivotal movement about a second axis parallel to said first axis and supporting said roller for rotation about a third axis parallel to and spaced from said second axis, said first and second axes lying in a common plane and being spaced apart by a distance greater than said radius but less than the sum of said radius and the distance between said second and third axes, for causing said roller to bear against said arcuate periphery with greater force when said member moves in one of said directions than when said member moves in the other of said directions; and
. means for exerting a damping force on said roller to oppose oscillation of said member incident to movement of said member in said one direction 18. Apparatus as defined in claim 17, wherein said damping means comprises at least one blade carried by said roller for rotation therewith and so shaped that air resistance to rotation of said blade exerts a damping force on said roller.
19. Manually controllable apparatus for dispensing metered quantities of flowable material, comprising:
a. a container for the material having a discharge outlet;
b. a valve member for opening and closing the outlet, biased toward outlet-closing position but movable to a position at which the outlet is open;
'. releasable means for engaging and retaining said valve member in outlet-opening position; and
d. means for releasing said releasable means, to permit said valve member to close said outlet, in response to discharge of a predetermined quantity of the material through said outlet following movement of the valve member to outlet-opening position, said releasing means including a pivotally mounted pan for receiving material discharged through said outlet and tippable to dump material received on the pan;
e. an arm connected to said valve member for movement therewith; and
f, a manually controllable valve opening member, separate from and movable independently of said pan and said releasable means, biased to a first position and movable therefrom to a second position g. said arm having a portion displaceable in relation to said valve member for permitting return movement of said valve-opening member from said second position to said first position in said path without displacement of said valve member and regardless of the position of said valve member, so that each movement of said manually controllable member from its first position to its second position, beginning when said valve member is in its outlet-closing position, causes a single operation of said releasing means to discharge said predetermined quantity of material.