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(11) | EP 0 317 534 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Dispensing device |
| (57) A dispensing device is disclosed which comprises a hopper (72) for receiving a substance
to be dispensed, at least one dispensing spoon (50), extendable and retractable cylinder
(120) for moving the spoon (50) from a position beneath said hopper (72) for receiving
said substance to a position remote from said hopper (72) and cylinder (150), linkages
(56, 54) and cylinder (22) for tilting said spoon and for causing said spoon to rotate
about its axis to dispense said substance from the spoon to a receptacle. |
[0001] This invention relates to a dispensing device and in particular, to a dispensing device for use with the sample preparation apparatus disclosed in our Australian Patent Application No. PI3575. The subject matter of that Australian application is incorporated into this specification by this reference.
[0002] In a first aspect the invention provides a dispensing device comprising a hopper for receiving a substance to be dispensed, at least one dispensing element, means for moving said dispensing element from a position beneath said hopper for receiving said substance to a position remote from said hopper and means for causing said dispensing element to dispense said substance from the dispensing element to a receptacle.
[0003] Preferably the receptacle into which the substance is deposited comprises a crucible held in the apparatus disclosed in our abovementioned Australian patent application.
[0004] Preferably the means for moving the said dispensing element comprises ram means for moving said element from the position beneath said hopper to said remote position. Preferably a plurality of dispensing elements are provided and moving means is provided for moving said hopper so that said hopper can be located above a selected dispensing element to deposit said substance onto said selected dispensing element.
[0005] Preferably, said device comprises means for shaking said hopper such that the substance contained in said hopper is disturbed to prevent said substance from setting or solidifying into a generally solid mass.
[0006] Preferably said means for causing said dispensing elements to deposit said substance into said receptacle comprises means for rotating said dispensing elements so that said substance can be tipped from said dispensing elements into said receptacle.
[0007] A preferred embodiment of the invention will be described with reference to the accompanying drawings in which:
Figure 1 is a plan view of a device embodying the invention;
Figure 2 is a view along the line 2-2 of Figure 1; Figure 3 is a view along the line 3-3 of Figure 2;
Figure 4 is a view along the line 4-4 of Figure 2;
Figure 5 is a view of a second embodiment of part of the invention; and
Figure 6 is a view of a third embodiment of part of the invention.
[0008] With reference to Figure 1, the device comprises a pair of end frame members 12 which extend between upright frame members 13. Inner frame members 14 are pivotally connected to front upright frame members 13 by pivot pins 16. The inner frame members 14 are joined by a cross member 18 connected at the rear thereof and a cross member 19 connected at the front thereof. It should be noted that the cross member 18 is only partly shown for the sake of clarity in Figure 1. A hydraulic or pneumatic cylinder 22 is connected to each of the members 14 at the ends of the device. One of the cylinders 22 is partly shown in dotted lines in Figure 1 and is shown in more detail in Figure 2. The cylinders 22 have rams 24 which are coupled to lugs 26 which are in turn coupled to the members 14. The members 14 are also provided with abutment members 32 which have flanges 34 which sit on cushions 36 secured to the frame members 13.
[0009] A pair of rails 40 extend between the member 18 and 19 and have mounted thereon a moveable bar 20 and a fixed block 42. A plurality of dispensing spoons 50 are coupled between the rail 20 and block 42 and are provided with spoon shaped recesses 52 at their remote end. The dispensing spoons are fixed to the bar 20 so that they cannot move in the longitudinal direction relative to the bar 20 and for sliding movement through the block 42. The opposite end of the dispensing spoons 50 pass through the bar 20 and are coupled to one end of a rod 54. The other end of the rod 54 is pivotally coupled to a link 56.
[0010] A further inner frame member 58 is arranged inwardly of the frame members 14 and is pivotally coupled by a pivot pin 60 (only one of which is shown in Figure 1) to links 63. The members 58 are arranged on adjustment rails 91 which extend between the members 14. A pair of rails 64 are arranged between the links 63 and extend through a pair of struts 66. One of the struts 66 abuts one of the links and the other link 63 is spaced from strut 66 by a spacer 67 arranged on the rails 64. A screw threaded shaft 68 is mounted to one strut 66 by a bearing housing 88 and has a reduced diameter portion 68a which extends through the other strut and holds that strut against the spacers 67 by a washer 69. The struts 66 are therefore held fixed relative to one another by the shaft 68. A carriage 70 is mounted on the rails 64. The carriage 70 supports a hopper 72 which has a lower end 74 arranged slightly above the dispensing spoons 50. A motor 80 is connected to one of the cross members 66 and drives screw threaded shaft 68 by means of a belt 82 and pulleys or gears 84 and 86.
[0011] A pair of pneumatic or hydraulic cylinders 90 are coupled to each end of the device and comprise a first cylinder 92 coupled to member 58 and having a ram 94 and a second cylinder 96 coupled to link 63 and having a ram 98. The rams 94 and 98 are coupled together by a generally Z-shaped link 100. The cylinder 92 is securely coupled to the frame member 58 by a bracket 102 and the cylinder 96 is securely coupled to the link 63 via lugs 104.
[0012] As is best seen in Figure 3 the hopper 72 is provided with a pair of flanges 106 which support cylinders 108. The cylinders 108 have rams 110 which are coupled to a link 112. The link 112 is coupled to a rod 114 which extends inside the hopper 72 through a lid 116 of the hopper and is guided by stems 113. The lid 116 may be supplied with hoses 120 to supply a substance to be dispensed to the hopper 72.
[0013] Arranged in the centre of the device is a pair of cylinders 120 which comprise a first cylinder 122 and a second cylinder 124. A generally Z-shaped link 126 (similar to the link 100) is connected between the two cylinders so that a ram 130 of the cylinder 124 is connected to one end of the link 126 and a ram 132 of the cylinder 122 is connected to the opposite end of the Z-shaped link 126. The cylinder 122 is connected to the member 20 by a rod 140 and the cylinder 124 is securely connected to the member 19 by a bracket 142.
[0014] In order to dispense substance from the hopper 72 the cylinders 108 are actuated to raise link 112 to in turn raise rod 114 which opens the open end 118 of the hopper 72 to allow substance to dispense from the hopper into the recess 52 in the spoon dispenser 50.
[0015] In order to dispense the substance from the spoon dispenser 52 the cylinders 122 and 124 are actuated to extend their rams 130 and 132. Since the cylinder 124 is fixed to member 19 and the cylinder 126 is connected to the bar 20 and the cylinders themselves are interconnected by link 126 the bar 20 is caused to slide on rails 40 relative to block 42 to move the spoon dispenser outwardly in the direction of arrow B. The cylinders 22 are then actuated to cause rams 24 to extend to thereby pivot the frame members 14 about pivot point 16. Pivotal movement of the frame members 14 in the direction of arrow A in Figure 2 also causes the entire assembly comprised of the inner frame members 58, cross members 18 and 19, rails 20 and block 42 together with the dispenser spoons 50, carriage 70 supported on rails 64 and hopper 72 to be pivoted in the direction of arrow A. When the assembly has been pivoted so that the end of the assembly remote from the pivot pins 16 has been raised, the spoons dispensers 50 are tilted so that they are arranged just above a receptacle into which the substance is to be deposited. In an alternative embodiment the assembly could be tilted before the dispenser spoons are moved outwardly.
[0016] When the dispenser spoons 50 having the substance in the recesses 52 are in the position outwardly of the device and above a suitable receptacle into which the substance is to be tipped, a cylinder 150 which is best seen in Figure 4 is actuated to withdraw its ram 152 in the direction of arrow D to thereby cause the rods 54 to pivot around the longitudinal axes of the dispenser spoons 50 to thereby rotate the dispenser spoon 50 in the direction of arrow E which tips the substance from the recesses 52 into the receptacle. In order to return the dispenser spoons to their normal position, the cylinder is actuated to extend the ram 152 so that the blocks 54 rotate in the direction opposite arrow E so that the dispenser spoons 50 are returned to their normal upright position.
[0017] The link 56 has a fixed abutment 57 connected to one of its ends which moves with the link 56 when the rods 54 pivot about the axes of the spoon dispensers 50. An adjustable stop 59 is coupled to the member 20 so that when the ram 142 is extended to return the spoons to their upright position the abutment 57 contacts the stop 59 to prevent further movement of the link 56, rods 45 and therefore the spoons 50 to ensure that the spoons 50 are stopped in their correct upright position to enable the recesses 52 to receive a further deposit of substance from the hopper 72.
[0018] In order to retract the dispensing spoons back into the position shown in Figures 1 and 2, the cylinders 122 and 124 are actuated to withdraw their rams 130 and 132 to thereby cause the member 20 and block 42 to be drawn in the direction of arrow C in Figure 2 so that the members 20 and block 42 slide on rails 40 to thereby return the dispensing spoons 50 back to the position shown in Figures 1 and 2.
[0019] In the preferred embodiment of the invention the substance to be dispensed comprises or includes ammonium iodide and the amount to be dispensed varies from 10 mg to 40 mg. This substance which is normally in powder form tends to solidify or form a solid lump if left standing. Thus, in order to prevent this from happening the invention intermittently shakes the hopper 13 to maintain the substance in its powdered form. In order to shake the hopper the cylinders 92 and 96 are actuated to withdraw their rams 94 and 98 to thereby cause the links 63 to pivot about pivot pins 60 in the direction of arrow F in Figure 2. This pivotal movement causes the rails 64, struts 66 together with the carriage 70 and hopper 72 to also pivot in the direction of arrow F with the links 63. The cylinders are quickly actuated again to extend the rams 94 and 98 to return the link 63 and the hopper 72 to its normal position so that the pivotal movement in the direction of arrow F, then the return movement, tends to shake the hopper 72 to maintain the substance in its powdered form. Actuation of the cylinders 92 and 96 can take place every, for example, 30 seconds to maintain the substance in the powdered form. It will be evident that since the cylinders 92 and 96 form part of the assembly which is generally held by the frame members 14 the cylinders 92 and 96 can shake the hopper 72 regardless of whether the assembly is in the elevated position in which the dispenser spoons are extended or in the normal position shown in Figures 1 and 2. The links 63 have stops 65 which abut the members 58 to support the links in their lowered position.
[0020] A rail 170 extends between the further inner frame members 58 and is provided with apertures for receiving sensors 172. The sensors 172 sense the position of a projection 174 connected to carriage 70 so that the position of carriage 70, and therefore the hopper 72, can be determined. Further sensors 174 and 176 are coupled to the member 170 and to the frame member 18 for sensing the position of the member 20 to provide an indication of whether the dispenser spoons are in the retracted or extended positions.
[0021] In the preferred embodiment of the invention all of the cylinders described above together with the sensors are controlled by suitable microprocessor or computing apparatus. The hopper 72 can be located above any of the dispenser spoons 50 and deposit a predetermined amount of substance onto those spoons by varying the actuation time of the cylinders 108 to vary the amount of time the bottom 118 of the hopper 172 is opened. Thus, a predetermined amount of substance can be deposited on predetermined spoons for depositing into the receptacles.
[0022] A sensor 180 is also coupled to the member 20 for detecting the position of the rods 54 so that the orientation of the spoon dispensers can be determined. That is, whether the spoon dispensers are in the upright position or in the rotated position whereby the contents have been tipped from the spoon dispensers.
[0023] The members 58 which are mounted on rails 91 allow the members 58 and the block 42, bar 20, dispensing spoons 50 and hopper 72 etc. to be moved sideways to adjust the alignment of the dispenser spoons if they are not accurately located above the receptacles.
[0024] With reference to Figure 5, a second embodiment of the hopper 72 is shown. The other parts of the device are identical to those described with reference to Figures 1 to 5. In the embodiment of Figure 5, the hopper 72 is supported by the carriage 70 in the same manner as described with reference to Figures 1 to 4. The manner of dispensing the substance from the hopper 72 is different in the embodiment of Figure 5. In the embodiment of Figure 5, the carriage 70 also supports a pair of cylinders 300 (only one of which is shown in Figure 5) which have ram arms 302 and 304 which extend in opposite directions. The ram arms 302 and 304 are connected by L-shaped links 306 to plates 308 and 310, respectively. The plate 308 is provided with an aperture 312 which is sized to receive a single bead of material from the hopper 72. If the material contained within the hopper 72 is in forms other than a bead, the size of the opening 312 can be such that a desired amount of material is received in the opening 312. The opening 312 is normally closed by the second plate 310 and therefore defines a chamber of a predetermined size. In order to deposit the material from the hopper 72 into a spoon 50, the ram arm 302 is extended to move plate 308 in the direction of arrow A. This causes the aperture 312 to be brought into alignment with an aperture 314 in the plate 310. As the plate 308 is moved in the direction of arrow A the portion of the plate designated by reference 316 closes the hopper 72 to prevent further material being dispensed from the hopper 72. When the aperture 312 is brought into alignment with the aperture 114, the material contained in the aperture 312 falls through the aperture 314 into the spoon 50.
[0025] The second of the rams 300 can move its ram arm 304 to cause the plate 310 to move so that the aperture 314 is correctly aligned with the spoon 50 if necessary. In order to fill a further spoon the plate 306 is moved by the ram arm 302 in the direction opposite to arrow A to realign the aperture 312 with the hopper 72 to receive further material and the carriage 70 moves the hopper 72 to align the carriage with another spoon 50. Sensors (not shown) may be used to ensure that the aperture 314 is aligned above a spoon 50 and any adjustment can be made by moving the plate 310 by means of its ram 300 and ram arm 304.
[0026] The embodiment of Figure 5 provides a device which ensures accurate and safe deposition of material from the hopper 72 into a spoon 50. Furthermore, the precise amount of material to be dispensed can be controlled and ensured by virtue of the fact that the aperture 312 can be sized to receive only one bead or a certain amount of material and the hopper 72 securely closed by the portion 316 of the plate 308 when the plate is moved to deposit the material from the aperture 312 into the spoon 50.
[0027] A third embodiment of the hopper is shown in Figure 6 and in particular a third manner of dispensing a bead of material from the hopper 72. The dispensing mechanism includes a block 401 arranged at outlet 409 of the hopper and which receives a shaft 403 which is rotatable in the block 401 within a nylon bush 405. The shaft 403 has a plurality of holes 407 therein. Preferably, four holes are provided in the shaft about the circumference of the shaft and the four holes are arranged 90° apart. The outlet 409 of the hopper 72 communicates with a passage through the block 401 and sleeve 405 and is aligned with a generally vertical plane which contains the holes 407. The bottom of the block 401 is provided with an outlet passage 411. The shaft 403 may be provided with a circlip 413 and a plurality of O-rings 415 to securely but releasably retain the shaft within the block 401 and allow the shaft to rotate within the block 401.
[0028] In order to dispense beads from the hopper 72, the bead is allowed to drop from the hopper 72 into the opening 407 which is arranged directly below the outlet 409. Rotation of the shaft 403 will move that hole 407 firstly into a position between the outlet 409 and outlet passage 411 (i.e. into the position of the hole 407 shown in Figure 6) and the next hole will be brought into alignment with the outlet 409 to enable another bead to drop into that hole. Further rotation of the shaft will cause the hole which contains the first bead to be brought into alignment with the outlet 411 so that the bead can drop through the outlet 411 into a spoon 50 (not shown in Figure 6). This, in turn, brings the next hole into alignment with the outlet 409 and places the previous hole with its bead into the position shown in Figure 6. Continued rotation of the shaft 403 will enable beads to drop into holes 407 and to be dispensed from the passage 411.
[0029] As the beads are dispensed from the hopper 72 a negative pressure will build up in the hopper 72. A one-way valve 419 is provided for allowing air to enter the hopper 72. Whilst air is allowed to enter through the one-way valve it is preferred that the pressure within the hopper 72 always be slightly less than atmospheric pressure.
[0030] This embodiment also provides a manner of dispensing a control amount of substance or a certain amount of beads from the hopper 72.
[0031] In the preferred embodiment the device described herein is intended for use with the apparatus described in our Patent Application No. PI3575. That apparatus is intended to be placed in front of the device shown in Figure 1 so that when the dispenser spoons 50 are extended outwardly of the device they are arranged above crucibles supported in the device disclosed in our abovementioned patent application so that the contents of the dispenser spoons can be deposited in those crucibles. The subject matter of our abovementioned patent application is hereby incorporated into this specification.
1. A dispensing device characterized by a hopper (72) for receiving a substance to
be dispensed, at least one dispensing element (50), means (120) for moving said dispensing
element from a position beneath said hopper for receiving said substance to a position
remote from said hopper and means (22, 150) for causing said dispensing element to
dispense said substance from the dispensing element to a receptacle.
2. The device according to Claim 1, wherein the receptacle into which the substance
is deposited comprises a crucible.
3. The device according to Claim 1 or 2 wherein the means (120) for moving the said
dispensing element comprises ram means (122, 124) for moving said element from the
position beneath said hopper to said remote position.
4. The device according to Claim 1, wherein a plurality of dispensing elements (50)
are provided and moving means (68, 70) is provided for moving said hopper (72) so
that said hopper can be located above a selected dispensing element (50) to deposit
said substance onto said selected dispensing element.
5. The device according to Claim 1, wherein said device comprises means (90) for shaking
said hopper (72) such that the substance contained in said hopper is disturbed to
prevent said substance from setting or solidifying into a generally solid mass.
6. The device according to Claim 1 wherein said means (22, 150) for causing said dispensing
elements to deposit said substance into said receptacle comprises means (150) for
rotating said dispensing elements and means (22) for tilting said dispensing elements,
so that said substance can be tipped from said dispensing elements into said receptacle.
7. The device according to Claim 1 wherein said hopper (72) has opening and closing
means (114, 310, 316, 403) for selectively opening and closing said hopper (72) to
allow the substance to be dispensed from said hopper onto said dispensing element.
8. The device according to Claim 7 wherein said opening and closing means comprises
a first plate (310) having a first aperture (312) and a second plate (316) having
a second aperture (314), means for moving said first plate from a position beneath
said hopper at which substance is disposed into said first aperture (312) to a second
position where the first aperture (312) aligns with the second aperture (314) to allow
said substance to enter said second aperture (314) and be dispensed from the second
aperture into the receptacle.
9. The device according to Claim 7, wherein said opening and closing means comprises
a rotatable shaft (403) which has a plurality of holes (407) therein, said shaft being
rotatable to align a hole (407) with an outlet (409) from the hopper so that material
can be dispensed into the hole (407) and said shaft (403) then being rotatable into
a position wherein the material within the hole (407) can be dispensed from the hole
(407).