GRINDING SAMPLES USING ROTATIONAL AND LINEAR MOTION

Abstract

The disclosure is directed to a sample preparation apparatus for grinding or homogenizing test samples. More specifically, the disclosure relates to grinding samples using rotational and linear motion. Grinding samples can be accomplished with an apparatus with a slider-crank mechanism that is attached to an oscillating connecting linkage. The amplitude of oscillatory motion can be greater than or equal to a length of a sample processing chamber.

Claims

1. An apparatus for generating a reciprocating motion for the purpose of grinding or homogenizing samples, the apparatus comprising: a connecting linkage that extends along a longitudinal axis; a holder, to hold a sample vial; a crank operatively connected at or near a first end of the connecting linkage, the crank configured to impart rotational motion to the first end of the connecting linkage, the crank having a diameter larger than a longitudinal length of a sample vial held by the holder; a sliding carriage operatively connected at or near a second end of the connecting linkage, the sliding carriage configured to restrict the second end of the connecting linkage to a linear path; and a motor operatively connected to the crank to rotate the crank, wherein the holder is configured to be secured to the connecting linkage at a variety of positions between the first end of the connecting linkage and the second end of the connecting linkage such that the holder, in use, moves with a combination of rotational and linear motion and the position of the holder on the connecting linkage changes the resulting pathway of the holder to be able to tailor the shape of the resulting pathway for grinding or homogenizing samples.

2. The apparatus of claim 1, wherein the connecting linkage is connected to the crank at or near an edge of the crank so that a longitudinal distance the holder travels during operation is equal to the diameter of the crank.

3. The apparatus of claim 1, wherein the diameter of the crank is greater than or equal to 1.5 inches.

4. The apparatus of claim 1, wherein the resulting pathway of the holder is approximately circular when the holder is coupled near the first end of the connecting linkage and the resulting pathway of the holder is approximately linear when the holder is coupled near the second end of the connecting linkage.

5. The apparatus of claim 1 further comprising a second holder configured to be secured to the connecting linkage at a different position from the holder such that the holder and the second holder experience different resulting pathways due to the different longitudinal positions of the holder and the second holder.

6. The apparatus of claim 1, wherein the motor is separated from the longitudinal axis in a direction perpendicular to the longitudinal axis and the motor is between the first end of the connecting linkage and the second end of the connecting linkage in a direction parallel to the longitudinal axis.

7. The apparatus of claim 1, wherein the motor is configured to cause the crank to rotate with a rate of at least 4,000 cycles per second.

8. An apparatus for generating a reciprocating motion for the purpose of grinding or homogenizing samples, the apparatus comprising: a crank operatively connected to a motor to cause the crank to rotate; a sliding carriage coupled to a rail that restricts the sliding carriage to move with linear motion along a longitudinal axis; a connecting linkage coupling the crank to the sliding carriage such that rotational motion of the crank causes linear motion of the sliding carriage, wherein the rail and the sliding carriage extend beyond an end of the connecting linkage; a first holder secured to the sliding carriage, the first holder having a first cavity with a first length configured to hold a sample vial within the first cavity; and a second holder secured to the connecting linkage, the second holder having a second cavity with a second length configured to hold a sample vial within the second cavity, wherein the first holder undergoes linear motion and the second holder undergoes elliptical motion.

9. The apparatus of claim 8, wherein a diameter of the crank is larger than the first length and the second length.

10. The apparatus of claim 8, wherein a longitudinal distance of travel of the first holder is greater than or equal to the first length.

11. The apparatus of claim 8, wherein a longitudinal distance of travel of the second holder is greater than or equal to the second length.

12. The apparatus of claim 8 further comprising a frame top, the rail coupled to the frame top.

13. The apparatus of claim 12, wherein the crank is configured to be secured to the frame top via a shaft that is coupled to a motor to impart rotational motion to the crank.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Further objects of the present invention together with additional features contributing thereto and advantages accruing therefrom will be apparent from the following description of the preferred embodiments of the invention which are shown in the accompanying drawing figures with like reference numerals indicating like components throughout wherein:

[0015] FIG. 1 is blow-up illustration of the apparatus of the present invention showing the individual components thereof;

[0016] FIG. 2 is an isometric view of the apparatus of the present invention; and

[0017] FIGS. 3A, 3B, 3C, and 3D are a top view of the apparatus of the present invention at four different angular positions of the crank.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

[0018] The components of the preferred embodiment of the apparatus of the present invention are shown in the blown-up illustration of FIG. 1. The individual components of the apparatus, with like reference numbers corresponding to the drawing of FIG. 1, are listed below in Table 3:

TABLE-US-00003 TABLE 3 Ref No. Description 10 crank 11 crank pivot 12 sliding carriage/carriage/slide 13 slide pivot 14 rail 15 rail screws 16 linkage or connecting linkage 18 holder 20 sample vial or tube 21 frame top 22 ceramic bead 26 motor 28 drive belt 30 small pulley 32 big pulley 34 spacer 36 spacer 38 big pulley shaft 40 small pulley shaft 42 frame bottom 44 threaded adapter 46 frame screws 48 adapter screws 50 crank pivot bolt 52 slide pivot bolt 54 slide pivot nut 56 top frame screw 58 slide pivot carriage screw 60 slide pivot bearing 62 crank pivot bearing 100 reference line

[0019] As illustrated in FIG. 1, a sample tube or vial (20) fits inside a holder (18). The holder (18) is attached to a connecting linkage or linkage (16). The linkage (16) sits on top of bearing pivots; the crank pivot (11) and slide pivot (13). The proximal end of the linkage (16) is attached to the crank pivot (11) via the top frame screws (56) while its distal end is attached to the slider pivot bearing (60) in the slider pivot (13) and is held in place via the slide pivot bolt (52) and slide pivot nut (54). The slide pivot (13) is connected to the sliding carriage or slide (12) via slide pivot carriage screws (58). The slide (12) sits on top of the rail (14) which is attached to the frame top (21) via slide screws (15). The crank pivot (11) is attached to the crank (10) via a crank pivot bearing (62). The crank (10) is connected to the big pulley (32) via the big pulley shaft (38). The big pulley (32) is driven or turned via a small pulley (30) through a drive belt (28). The small pulley (30) is connected to a small pulley shaft (40) which connects directly to the motor (26). The big pulley (32), big pulley shaft (38), drive belt (28) and the small pulley (30) are held in place between the frame top (21) and frame bottom (42) via frame screws (46) and spacers (34 and 36). The frame bottom (42) is attached to a threaded motor adapter (44) via adapter screws (48). The threaded motor adapter (44) allows for the attachment of the device of the present invention to the motor (26) which drives the small pulley (30) thereby moving the sample vial (20) in an elliptical path at a predetermined rate. In an alternate embodiment of the present invention, the sliding carriage (12) and rail (14) is made longer so that the holder (18) could be placed directly on the sliding carriage (12). The motion of the sample vial (20) is linear in this alternative embodiment.

[0020] With reference now to FIG. 2, there is depicted an isometric view of a fully assembled apparatus of the present invention with the sample vial (20) in vial holder (18) which is in turn mounted on the connecting linkage (16), which has a pivot point at each end for connecting it to sliding carriage (12) at the distal end and crank 10 at the proximal end as shown in FIG. 2. Slide/carriage (12) slides on rail (14), which is fixed to the frame top (21) of the apparatus as discussed above. Motor (26) is linked to crank (10) via small pulley (30), drive belt (28), and big pulley (32). As crank (10) is driven to rotate by motor (26), its rotational motion is converted to linear motion as carriage (12) slides on rail (14). Since holder (18) is placed approximately halfway between the crank (10) and carriage (12), it experiences a combination of linear and rotational motion, resulting in an elliptical trajectory of sample vial/tube (20).

[0021] The next figures, FIGS. 3A-D, show a top view of the apparatus at four angular positions of the cycle of crank (10), as it rotates in a counterclockwise direction. Also illustrated is a ceramic bead (22) that acts as pestle in grinding samples placed in the sample vial (20). Since the ceramic bead (22) has a high finite inertia, it will tend to stay in place at the level of reference line (100) while vial (20) surrounding it reciprocates in an elliptical path.

[0022] Specifically, FIG. 3A depicts the ceramic bead (22) at midway the length of the vial (20), pressed against its left wall as it travels towards the top. FIG. 3B depicts the bead (22) impacting the top end of the tube. FIG. 3C depicts the ceramic bead (22) again midway the length of the tube, pressed against the right wall as it travels towards the bottom of the tube. Finally, the ceramic bead (22) impacts the bottom of the tube in FIG. 3D.

Operation

Example 1

[0023] 1. A sample to be ground or homogenized, if liquid is present, is inserted into a sample vial (20) that has preloaded hard grinding matrices [ceramic beads (22)] inside.

[0024] 2. The vial (20) is sealed and inserted into the holder (18) of the device.

[0025] 3. The device is turned on for a set period of time (usually 5 seconds or less, for example) at about 4,000 to 5,000 cycles per second to cause the sample to be ground or homogenized.

[0026] 4. The tube is removed from the holder and unsealed to remove the ground sample for analysis.

Example 2

[0027] 1. The user determines the optimal location for the holder on the connecting linkage.

[0028] 2. The holder is attached onto the connecting linkage at the predetermined optimal location (distance from the crank pivot) to allow optimal grinding or homogenization of a sample.

[0029] 3. A sample to be ground or homogenized, if liquid is present, is inserted into a sample vial (20) that has preloaded hard grinding matrices [ceramic beads (22)] inside.

[0030] 4. The vial (20) is sealed and inserted into the holder (18) of the device.

[0031] 5. The device is turned on for a set period of time (usually 5 seconds or less, for example) at about 4,000 to 5,000 cycles per second to cause the sample to be ground or homogenized.

[0032] 6. The tube is removed from the holder and unsealed to remove the ground sample for analysis.

Concluding Statements

[0033] All patents, provisional applications, patent applications and other publications mentioned in this specification are herein incorporated by reference.

[0034] While this invention has been described in detail with reference to certain preferred embodiments, it should be appreciated that the present invention is not limited to those precise embodiments. Rather, in view of the present disclosure, which describes the current best mode for practicing the invention, many modifications and variations would present themselves to those of skill in the art without departing from the scope and spirit of this invention. The scope of the invention is, therefore, indicated by the following claims rather than by the foregoing description. All changes, modifications, and variations coming within the meaning and range of equivalency of the claims are to be considered within their scope.

[0035] Furthermore, those skilled in the art will recognize, or be able to ascertain, using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.