Apparatus for use in sampling aggregate

A sample collector for aggregate material is provided. The collector includes a support frame having a first end and a second end. A pair of guide plates are attached to the first end of the support frame. These guide plates are spaced apart so as to define a collection space therebetween. At least one of the guide plates is provided with a track that extends generally along the periphery of the collection space. A flexible closing plate is disposed between the guide plates and is adapted for sliding engagement with the track, so that the closing plate may be moved between an open position which exposes the collection space and a closed position which encloses the collection space. A mechanism is also provided for sliding the closing plate between the open position and the closed position.

FIELD OF THE INVENTION
 This invention relates generally to the sampling of aggregate materials,
 especially to the sampling of such materials from a truck, railcar, barge
 or other conveyance. A preferred embodiment of the invention provides an
 apparatus for the sampling of bituminous paving materials.
 BACKGROUND AND DESCRIPTION OF THE PRIOR ART
 Sampling of various aggregate materials is commonly required in the
 construction and mining industries to insure that the materials meet the
 required specifications for quality, composition and/or gradation. Samples
 of the aggregate product may be taken at various stages in the process
 from production or manufacture to delivery to the customer. Samples may be
 taken from stockpiles, silos or other storage facilities, or they may be
 taken from trucks, barges, railcars, conveyors or other transport vehicles
 or devices.
 It is common for producers of aggregate materials to sample their product
 at several stages, including the shipping stage. In addition, the
 purchaser will almost always sample at least a portion of the incoming
 shipments before unloading them to insure that they are acceptable.
 Aggregate materials that are hauled by truck are usually sampled by hand
 shoveling a sample portion from various locations in the aggregate load in
 the truck bed, in order to obtain a representative sample. Because the
 aggregate may segregate by size as it is being loaded and hauled, however,
 hand sampling in this way makes it difficult to obtain a representative
 sample. It is generally necessary to remove a portion of the surface
 material from several locations in the truck bed in order to obtain a
 sample portion from therebeneath. However, when the aggregate material is
 bituminous paving material such as asphalt concrete, its surface
 temperature may be as high as 250-300.degree. F., which makes hand
 sampling at least uncomfortable and potentially dangerous. Furthermore, a
 worker who is charged with the responsibility of obtaining a hand sample
 from an asphalt concrete truck will not likely be willing and may not be
 able to spend the time to take sample portions from various locations on
 the load in the truck bed to insure that he gets a representative sample.
 Nevertheless, the standard practice for sampling bituminous paving
 mixtures from truck transports is to take several portions of a sample
 from each truck using a flat-bottom scoop or a square-nose shovel.
 ASTM Designation D 979-96 specifies that at least three approximately equal
 increments should be taken from each truck load of bituminous paving
 materials sampled. Various state highway departments impose additional
 requirements on the sampler of asphalt concrete, in an effort to insure
 that representative samples are obtained. For example, the Georgia
 Department of Transportation Sampling Procedure GSP-15 specifies that hand
 samples may be taken only after the "cone" of material in the bed of the
 truck is first shoveled off to a depth such that the resulting flat area
 is at least 60% as wide as the truck and at least six inches deep. Wyoming
 Department of Transportation Sampling Procedure 830.0 requires that for
 smaller trucks, a sample area must be prepared by removing the top 2-4
 inches from each quarter of the load, while for larger trucks, at least
 two transverse trenches must be excavated across the load in the truck
 bed. The sample is then removed by pushing the shovel into each cleared
 area or trench at a 45.degree. angle. Illinois Department of
 Transportation Sampling Procedure 4.7.1 requires that an equal amount of
 material is to be taken from locations approximately one foot below the
 top of each pile in the truck bed, at quarter points around the pile's
 circumference. Mississippi Department of Transportation Field Testing
 Procedure TMD-11-77-00-000 requires that at least three samples be taken
 from specified locations in the truck after first removing the top 2-3
 inches of material at each sample point. All of these procedures require
 that the sampler work for a significant period of time in the bed of the
 truck atop the load of hot asphalt concrete. Complying with such
 procedures is uncomfortable and may be dangerous, which makes proper
 sampling problematic.
 It would be desirable therefore if an apparatus could be developed that
 would permit the taking of samples from a truck or other conveyance
 quickly and safely. It would also be desirable if such apparatus would
 eliminate the need for the worker charged with obtaining the sample to
 climb into the truck bed and onto the load therein.
 ADVANTAGES OF THE INVENTION
 Among the advantages of the invention claimed herein is that the sample
 collector for aggregate material may be operated to obtain a
 representative sample of such material without requiring removal of the
 surface layer of material being sampled. Another advantage is that the
 sample collector may be operated remotely so that a worker that is charged
 with obtaining a sample from a truck or other means of conveyance is not
 required to climb onto the load of material to obtain the sample.
 Additional advantages of this invention will become apparent from an
 examination of the drawings and the ensuing description.
 EXPLANATION OF TECHNICAL TERMS
 As used herein, aggregate materials refers to particulate materials that
 may be transported in bulk, including bituminous paving mixtures such as
 hot-mix asphalt and cold mix, crushed limestone and other types of stone,
 gravel, sand, lime, coal, coke, fertilizer, grain, pellets and similar
 materials.
 As used herein, bituminous paving mixtures refers to mixtures of various
 aggregates, including crushed stone, sand, lime and the like, with asphalt
 cement or asphalt binder, which mixtures are prepared for paving purposes.
 As used herein, asphalt cement or asphalt binder refers to a black or brown
 tar-like substance, a type of bitumen that occurs naturally or is obtained
 from the distillation of coal tar, wood tar or petroleum.
 As used herein, asphalt concrete refers to a bituminous paving mixture that
 is prepared, using hot asphalt cement or asphalt binder, in a hot-mix
 asphalt plant. A synonymous term is hot-mix asphalt.
 As used herein, cold mix refers to a bituminous paving mixture that is
 prepared without the use of hot asphalt cement or asphalt binder.
 As used herein, sampler refers to a person who is charged with the
 responsibility for taking or collecting samples of aggregate material.
 SUMMARY OF THE INVENTION
 The invention comprises a sample collector for aggregate material, and
 includes a support frame having a first end and a second end. A pair of
 guide plates are attached to the first end of the support frame. These
 guide plates are spaced apart so as to define a collection space
 therebetween. At least one of the guide plates is provided with a track
 that extends generally along the periphery of the collection space. A
 flexible closing plate is disposed between the guide plates and is adapted
 for sliding engagement with the track, so that the closing plate may be
 moved between an open position which exposes the collection space and a
 closed position which encloses the collection space. Means are also
 provided for sliding the closing plate between the open position and the
 closed position.
 In order to facilitate an understanding of the invention, the preferred
 embodiments of the invention are illustrated in the drawings, and a
 detailed description thereof follows. It is not intended, however, that
 the invention be limited to the particular embodiments described or to use
 in connection with the apparatus illustrated herein. Various modifications
 and alternative embodiments such as would ordinarily occur to one skilled
 in the art to which the invention relates are also contemplated and
 included within the scope of the invention described and claimed herein.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
 Referring now to the drawings, FIGS. 1 and 2 illustrate a preferred
 embodiment of the invention, a sample collector assembly that is adapted
 for sampling of aggregate materials from a conveyance such as a truck. As
 shown therein, assembly 10 includes frame portions 12, 14, 16 and 17 (FIG.
 2), preferably made of steel or other suitable material, that generally
 define a truck zone 18 into which truck 20, containing a load of aggregate
 material 22, may be driven. Of course, the frame of the assembly may be
 arranged in any convenient configuration, depending on whether the samples
 are to be taken from trucks, railcars, barges, conveyors or from
 stationary stockpiles.
 Frame portions 16 (shown in partial cutaway in FIG. 1) and 17 define an
 overhead rail that is suspended over and adjacent to the truck zone.
 Platform 24 is also located adjacent to the truck zone, and is surrounded
 by safety rail 26. Platform 24 is elevated by support legs, including legs
 28 and 30, which are mounted on base 32. Staircase 34 provides access to
 the platform from ground level. The platform may be utilized by an
 operator of the sample collector assembly, or the assembly may be operated
 remotely by use of a video camera and a remote collector actuator (not
 shown) such as are known to those having ordinary skill in the art to
 which the invention relates. If remote operation is desired, the assembly
 may also include a small elevator or other conveyor (also not shown) to
 transport a sample taken by the collector to a ground level collection
 station. Such an elevator may be mounted on or adjacent to frame portion
 12.
 Carriage 36 is adapted to ride on overhead rails 16 and 17 by means of
 rollers 38 and 40 between a first position adjacent to the truck zone
 (shown in FIG. 1) and at least one sampling position over the truck zone
 (not shown). Hydraulic cylinder 42 is mounted on the overhead rails and
 the carriage and is provided with piston 43 that is attached to the
 carriage so that the cylinder may move the carriage between the first
 position adjacent to the truck zone (shown in FIG. 1) and at least one
 sampling position over the truck zone. Of course, other means and
 mechanisms for moving the carriage between the first position and the
 sampling positions as are known to those skilled in the art to which the
 invention relates, as well as those subsequently developed, are also
 included within the invention.
 Sample collector subassembly 44, including sample collector 45, is mounted
 on the carriage at mounting point 46. In one embodiment of the invention,
 the sample collector subassembly is mounted so as to pivot about mounting
 point 46. In this embodiment, it is preferred that the sample collector
 subassembly be mounted to pivot on the carriage so as to permit the sample
 collector to be inserted into the aggregate along an axis that is disposed
 at any angle within the range of about 30.degree. to about 150.degree.
 from the horizontal. In another embodiment of the invention, the sample
 collector subassembly may be mounted on carriage 36 at mounting point 46
 at a fixed angle, such as at 60.degree. from the horizontal. In yet
 another embodiment of the invention, the sample collector subassembly may
 be provided in the form of a portable unit that may be carried by the
 sampler, especially if it is used to sample stockpiled material.
 FIGS. 3 through 7 illustrate a preferred embodiment of the sample collector
 in more detail. As shown therein, sample collector 45 includes support
 frame 48, having first end 50 and second end 52. It is generally preferred
 that the support frame be provided in the form of a length of tubing
 having a pair of generally planar sides, each of which is disposed
 generally parallel to the other. The support frame may be provided in a
 square, rectangular, hexagonal or other convenient cross-section.
 Preferably, as shown in FIGS. 3-7, frame 48 is a length of square tubing
 that is made of steel or other suitable material. As shown on FIG. 1,
 subassembly 44 also includes elongate extension 54, which is attached to
 the second end 52 of the support frame of collector 45, and boom 56, to
 which the elongate extension is mounted. These components are also
 preferably made from steel or other suitable material. Preferably
 extension 54 is mounted in sliding engagement within boom 56, and is
 adapted to telescope therefrom. Hydraulic cylinder 58 is attached to boom
 56 and provided with piston 60, which is attached to extension 54, so that
 cylinder 58 may move extension 54 from a retracted position (shown in FIG.
 1) to an extended position (not shown) for inserting collector 45 into the
 aggregate material in the truck. Of course, hydraulic cylinder 58 of the
 preferred embodiment of the invention that is illustrated in FIG. 1 may be
 replaced by other means for moving the extension with respect to the boom
 as are known to those having ordinary skill in the art to which the
 invention relates, or which may be subsequently developed.
 A pair of guide plates 62 and 64 are attached to first end 50 of the
 support frame. The guide plates are spaced apart so as to define a
 collection space therebetween, and at least one of the guide plates is
 provided with a track that extends generally along the periphery of the
 collection space. Preferably each of the guide plates is provided with a
 pair of tracks 66A and 66B so that each track on a guide plate extends
 generally along one side of the periphery of the collection space to a
 common termination point 68, and so that the tracks on guide plate 62 (not
 shown) are generally parallel to the tracks on guide plate 64.
 Sample collector 45 also includes at least one flexible closing plate which
 is disposed between the guide plates and adapted for sliding engagement
 with the track so that the closing plate may be moved between an open
 position which exposes the collection space and a closed position which
 encloses the collection space. Preferably, as shown in FIGS. 3, 3A, 4, 4A
 and 5, a pair of flexible closing plates 70A and 70B (see FIGS. 4A and 5)
 are provided. It is also preferred that the closing plates are attached to
 a carrier which is adapted to move along the support frame. As shown in
 FIGS. 3, 4 and 6, carrier 72 is preferably comprised of tubing component
 74 having a first end 76 and a second end 78, to which (at first end 76) a
 pair of mounting plates 80A and 80B (see FIG. 6) are attached.
 Furthermore, the closing plates are preferably attached to the mounting
 plates on opposite sides of the carrier. Thus, as illustrated in FIGS. 3
 and 4, flexible closing plate 70A is attached to mounting plate 80A. It is
 generally preferred that the carrier be provided in the form of or include
 a length of tubing having a pair of generally planar sides, each of which
 is disposed generally parallel to the other. As is the case with respect
 to the support frame, the carrier tubing component may be provided in a
 square, rectangular, hexagonal or other convenient cross-section.
 Preferably, as shown in FIGS. 3, 4 and 6, tubing component 74 of carrier
 72 is a length of square tubing that is made of steel or other suitable
 material. Obviously, if support frame 48 and tubing component 74 of
 carrier 72 are provided in the telescoping relationship illustrated in the
 drawings, their shapes must be compatible with such physical arrangement.
 Furthermore, in order that tubing component 74 may easily slide outside of
 support frame 48, glide strips 82 are preferably provided between
 component 74 and frame 48. These glide strips are preferably made of steel
 or other suitable material and may be applied either to the outer surface
 of support frame 48, as shown in FIGS. 3 and 6, or to the inner surface of
 the tubing component of the carrier, as shown in FIG. 12 (as subsequently
 described).
 Carrier 72 is adapted to move along support frame 48 between an open
 position in which the closing plates expose the collection space and a
 closed position in which the closing plates enclose the collection space.
 Preferably, such motion is actuated by hydraulic cylinder 84. As shown in
 FIG. 4, hydraulic cylinder 84 includes piston 85 which is attached to
 second end 78 of tubing component 74 of carrier 72. The cylinder is also
 preferably attached to support frame 48 so that extension of piston 85
 from cylinder 84 (or retraction of piston 85 into cylinder 84) will move
 tubing component 74 of carrier 72 with respect to the support frame
 between an open position in which the closing plates expose the collection
 space (FIG. 3) and a closed position in which the closing plates enclose
 the collection space (FIG. 4). Of course, hydraulic cylinder 84 of the
 preferred embodiment of the invention that is illustrated in the drawings
 may be replaced by other means for moving the carrier with respect to the
 support frame as are known to those having ordinary skill in the art to
 which the invention relates or which may be subsequently developed.
 It is preferred that each of tracks 66A and 66B comprises a groove in the
 guide plate into which the closing plates may be fitted in sliding
 engagement, although other track configurations such as a raised rail (not
 shown) may also be employed. Obviously whatever track configuration is
 employed, the closing plates will have to be compatible therewith so that
 sliding engagement will be maintained. It is contemplated that the term
 "sliding engagement" as used herein to describe the relationship between a
 closing plate and its associated track includes rolling engagement such as
 where the track is provided in the form of a raised rail and the closing
 plate is fitted with wheels that roll on either side thereof. In the
 preferred embodiment of FIGS. 3 and 4, however, both of the tracks in each
 guide plate are provided in the form of grooves. In addition, relief
 openings 86 and 87 are provided in guide plates 62 and 64 respectively
 (best shown in FIGS. 3A and 4A) in order that closing movement of the
 closing plates may purge the tracks of any sample material that may have
 accumulated therein when sample collector 45 is plunged into the material
 to be sampled. Such relief openings are particularly useful when the
 collector is used to sample sticky material such as bituminous paving
 mixtures. This embodiment of the invention also includes a reinforcing
 strip 88 mounted onto the leading edge of each of the closing plates (only
 one of which is illustrated in the drawings). These reinforcing strips,
 which are preferably made of steel, serve to minimize deflection of the
 closing plates as they close around a sample of aggregate. In addition,
 nose guard 89, preferably of steel, is mounted to guide plates 62 and 64
 adjacent to common termination point 68 in order to provide additional
 protection for the closing plates.
 Another feature of a preferred embodiment of the invention that may be
 particularly useful when the invention is employed to sample bituminous
 paving mixtures is sample extraction plate 90 that is disposed between the
 guide plates and which is adapted to push the sample out of the collection
 space. As illustrated in FIG. 7, it is preferred that the extraction plate
 be constructed of thick steel plate 91 to which a block or piece of thick
 tubing 92 is attached for added mass. In the preferred embodiment of the
 invention, the extraction plate is adapted to conform to the inside shape
 of support frame 48, but must be capable of moving between the guide
 plates so as to push the sample out of the collection space. As shown in
 schematic form in FIG. 7, it is also preferred that a wheel such as
 sprocket 93 be mounted within the support frame, and that a belt such as
 roller chain 94 be provided and disposed around the sprocket. The roller
 chain has a first end 95 that is attached to the second end 78 of tubing
 component 74 of carrier 72, and a second end 96 that is attached to the
 sample extraction plate, or to the block or tubing 92 which is attached to
 the extraction plate.
 Another feature of the preferred embodiment of the invention that is
 particularly useful in sampling hot-mix asphalt is heater 97 (best shown
 in FIGS. 3A and 4A) that is provided in at least one, and preferably both
 of the guide plates 62 and 64. Heater 97 is preferably a commercially
 available cartridge heater that is available from a number of sources, and
 may be connected to an electrical source by means of wires 98 and 99. The
 heater may be used to minimize sticking of hot-mix asphalt on the guide
 plates during the sampling process.
 In the practice of the embodiment of the invention illustrated in FIGS.
 1-7, truck 20 is driven into truck zone 18. Carriage 36 with sample
 collector subassembly 44 mounted thereon is moved by the action of
 cylinder 42 from the first position adjacent to the truck zone to a
 sampling position over the truck zone. Sample collector subassembly 44 is
 then pivoted (if pivotally mounted on carriage 36) about mounting point 46
 to the desired angle, preferably at about 60.degree. from the horizontal.
 Cylinder extension 54 may then be moved with respect to boom 56 by the
 action of cylinder 58 from a retracted position to an extended position so
 as to insert the collector into the aggregate material in the truck.
 Preferably, the collector is inserted so that the collection space is
 imbedded to a depth of at least about twelve inches in the material in the
 truck before the closing plates are opened to expose the collection space.
 This depth is preferred because the outer layers of material in the truck
 tend to become segregated as the truck is loaded. Consequently, a sample
 that is more likely representative of the entire load may be obtained from
 a depth beneath the surface layer of the aggregate. When the collector is
 placed in the desired position, piston 85 may be moved by the action of
 cylinder 84 to move carrier 72 back (along the arrow of FIG. 3) to the
 open position in which the closing plates expose the collection space.
 Cylinder extension 54 may then be moved with respect to boom 56 by the
 action of cylinder 58 so as to insert the collector further into the
 aggregate material in the truck. In the alternative, although not
 preferred, the collector may be placed in the aggregate with the closing
 plates in the open position to expose the collection space. As the
 collector is pushed further into the aggregate material (or alternatively,
 is pushed into the aggregate material), extraction plate 90 will be pushed
 to the back of the collection space and into support tubing 48. Piston 85
 may then be moved by the action of cylinder 84 to move carrier 72 forward
 (along the arrow of FIG. 4, and to the left as viewed in FIG. 7) to the
 closed position in which the closing plates enclose the collection space.
 As this occurs, extraction plate 90 is pulled back (to the right as viewed
 in FIG. 7) by roller chain 94 out of the collection space and into the
 support tubing, permitting the sample material to enter the collection
 space. Cylinder 58 may then be actuated to move extension 54 from the
 extended position to a retracted position to withdraw the collector from
 the aggregate material in the truck. Cylinder 42 may then be actuated to
 move the carriage to the first position adjacent to the truck zone. The
 collector subassembly 44 may be rotated (if necessary) to the preferred
 sample ejection position (not shown), typically at an angle of
 45-60.degree. from the horizontal. Piston 85 may then be moved by cylinder
 84 to move the carrier back to the open position in which the closing
 plates expose the collection space. As this occurs, ejection plate 90 is
 moved forward under the influence of gravity to push the sample out of the
 collector. Additional samples may then be taken, if desired, from other
 locations in the truck bed, by changing the angle, the location and/or the
 depth at which the probe is inserted into the aggregate, as well as by
 moving the truck within the truck zone, if desired.
 FIGS. 8 and 9 illustrate a second embodiment 145 of the sample collector,
 in which a single closing plate 170 is employed. Such an embodiment may be
 particularly useful in sampling lightweight aggregate that is less viscous
 or "sticky" than bituminous paving materials. Sample collector 145
 includes support frame 148, having first end 150 and second end 152.
 Support frame 148 is provided in the form of a length of square tubing
 that is made of steel or other suitable material. A pair of guide plates
 162 and 164 are attached to first end 150 of the support frame. The guide
 plates are spaced apart so as to define a collection space therebetween,
 and preferably each of the guide plates is provided with a track 166 that
 extends generally along the periphery of the collection space so that the
 track on guide plate 162 (not shown) is generally parallel to the track on
 guide plate 164.
 Sample collector 145 also includes flexible closing plate 170 which is
 disposed between the guide plates and adapted for sliding engagement with
 the track so that the closing plate may be moved between an open position
 which exposes the collection space and a closed position which encloses
 the collection space. Preferably, as shown in the drawings, track 166
 comprises a groove in the guide plate into which the closing plate may be
 fitted in sliding engagement. Closing plate 170 is attached to a carrier
 which is adapted to move along the support frame. Carrier 172 is
 preferably comprised of tubing component 174 having a first end 176 and a
 second end 178. In this embodiment of the invention, mounting plate 180 is
 attached to tubing component 174 at first end 176, and closing plate 170
 is attached to the mounting plate. Preferably, tubing component 174 of
 carrier 172 is a length of square tubing that is made of steel or other
 suitable material. In order that tubing component 174 may easily slide
 outside of support frame 148, glide strips 182 are provided on the outer
 surface of frame 148.
 Carrier 172 is adapted to move along support frame 148 between an open
 position in which the closing plate exposes the collection space and a
 closed position in which the closing plate encloses the collection space.
 Preferably, such motion is actuated by hydraulic cylinder 184. As shown in
 FIG. 9, hydraulic cylinder 184 includes piston 185 which is attached to
 second end 178 of tubing component 174 of carrier 172. The cylinder is
 also preferably attached to support frame 148 so that extension of piston
 185 from cylinder 184 (or retraction of piston 185 into cylinder 184) will
 move tubing component 174 of carrier 172 with respect to the support frame
 between an open position in which the closing plate exposes the collection
 space (FIG. 8) and a closed position in which the closing plate encloses
 the collection space (FIG. 9). This embodiment of the invention also
 includes a reinforcing strip 188 mounted onto the leading edge of the
 closing plate (see FIG. 8), in order to minimize deflection of the closing
 plate as it closes around a sample of aggregate. In addition, nose guard
 189 is mounted to guide plates 162 and 164 in order to provide additional
 protection for the closing plate. Sample extraction plate 190 is disposed
 between the guide plates and is adapted to push the sample out of the
 collection space in much the same way that sample extraction plate 90
 pushes a sample out of the collection space of collector 45. This
 embodiment of the invention also includes heater 197 that is provided in
 at least one, and preferably both of the guide plates 162 and 164.
 FIGS. 10 and 11 illustrate a third embodiment 245 of the sample collector,
 in which, like collector 145, a single closing plate is employed. Sample
 collector 245 includes support frame 248, having first end 250 and second
 end 252. Support frame 248 is provided in the form of a length of square
 tubing that is made of steel or other suitable material. A pair of guide
 plates 262 and 264 are attached to first end 250 of the support frame. The
 guide plates are spaced apart so as to define a collection space
 therebetween, and preferably each of the guide plates is provided with a
 track 266 that extends generally along the periphery of the collection
 space so that the track on guide plate 262 (not shown) is generally
 parallel to the track on guide plate 264.
 Sample collector 245 also includes flexible closing plate 270 which is
 disposed between the guide plates and adapted for sliding engagement with
 the track so that the closing plate may be moved between an open position
 which exposes the collection space and a closed position which encloses
 the collection space. Preferably, as shown in the drawings, track 266
 comprises a groove in the guide plate into which the closing plate may be
 fitted in sliding engagement. Closing plate 270 is attached to a carrier
 which is adapted to move along the support frame. Carrier 272 is
 preferably comprised of tubing component 274 having a first end 276 and a
 second end 278. In this embodiment of the invention, mounting plate 280 is
 attached to tubing component 274 at first end 276, and closing plate 270
 is attached to the mounting plate. Preferably, tubing component 274 of
 carrier 272 is a length of square tubing that is made of steel or other
 suitable material. In order that tubing component 274 may easily slide
 outside of support frame 248, glide strips 282 are provided on the outer
 surface of frame 248.
 Carrier 272 is adapted to move along support frame 248 between an open
 position in which the closing plate exposes the collection space and a
 closed position in which the closing plate encloses the collection space.
 Preferably, such motion is actuated by hydraulic cylinder 284. As shown in
 FIG. 11, hydraulic cylinder 284 includes piston 285 which is attached to
 second end 278 of tubing component 274 of carrier 272. The cylinder is
 also preferably attached to support frame 248 so that extension of piston
 285 from cylinder 284 (or retraction of piston 285 into cylinder 284) will
 move tubing component 274 of carrier 272 with respect to the support frame
 between an open position in which the closing plate exposes the collection
 space (FIG. 10) and a closed position in which the closing plate encloses
 the collection space (FIG. 11). This embodiment of the invention also
 includes a reinforcing strip 288 mounted onto the leading edge of the
 closing plate, in order to minimize deflection of the closing plate as it
 closes around a sample of aggregate. Sample extraction plate 290 is
 disposed between the guide plates and is adapted to push the sample out of
 the collection space in much the same way that sample extraction plate 90
 pushes a sample out of the collection space of collector 45. This
 embodiment of the invention also includes heater 297 that is provided in
 at least one, and preferably both of the guide plates 262 and 264.
 FIG. 12 illustrates a fourth embodiment 345 of the sample collector which
 is very similar to sample collector 245. Sample collector 345 includes
 support frame 348, having first end 350 and second end 352. Support frame
 348 is provided in the form of a length of square tubing that is made of
 steel or other suitable material. A pair of guide plates 362 and 364 are
 attached with top plate 363 therebetween to first end 350 of the support
 frame. The guide plates are spaced apart so as to define a collection
 space therebetween, and preferably each of the guide plates is provided
 with a track 366 that extends generally along the periphery of the
 collection space so that the track on guide plate 362 (not shown) is
 generally parallel to the track on guide plate 364.
 Sample collector 345 also includes a flexible closing plate (not shown)
 which is disposed between the guide plates and adapted for sliding
 engagement with the track so that the closing plate may be moved between
 an open position which exposes the collection space and a closed position
 which encloses the collection space. Preferably, as shown in the drawings,
 track 366 comprises a groove in the guide plate into which the closing
 plate may be fitted in sliding engagement. The closing plate is attached
 to a carrier which is adapted to move along the support frame. Carrier 372
 is preferably comprised of tubing component 374 having a first end 376 and
 a second end 378. In this embodiment of the invention, mounting plate 380
 is attached to tubing component 374 at first end 376, and the closing
 plate is attached to the mounting plate. Preferably, tubing component 374
 of carrier 372 is a length of square tubing that is made of steel or other
 suitable material. In order that tubing component 374 may easily slide
 outside of support frame 348, glide strips 382 are provided on the inner
 surface of tubing component 374.
 Carrier 372 is adapted to move along support frame 348 between an open
 position in which the closing plate exposes the collection space and a
 closed position in which the closing plate encloses the collection space.
 Preferably, such motion is actuated by hydraulic cylinder 384 in the same
 manner that hydraulic cylinders 84, 184 and 284 actuate similar motion in
 carriers 72, 172 and 272, respectively. Hydraulic cylinder 384 includes a
 piston (not shown) which is attached to second end 378 of tubing component
 374 of carrier 372. The cylinder is also preferably attached to support
 frame 348 so that extension of the piston from cylinder 384 (or retraction
 of the piston into cylinder 384) will move tubing component 374 of carrier
 372 with respect to the support frame between an open position in which
 the closing plate exposes the collection space (FIG. 12) and a closed
 position in which the closing plate encloses the collection space (not
 shown). This embodiment of the invention also includes a sample extraction
 plate (not shown), that is similar to extraction plates 90, 190 and 290 of
 collectors 45, 145 and 245, respectively. This extraction plate is
 disposed between the guide plates and is adapted to push the sample out of
 the collection space in much the same way that sample extraction plate 90
 pushes a sample out of the collection space of collector 45. Collector 345
 also includes heater 397 that is provided in top plate 363.
 Although this description contains many specifics, these should not be
 construed as limiting the scope of the invention but as merely providing
 illustrations of some of the presently preferred embodiments thereof, as
 well as the best mode contemplated by the inventor of carrying out the
 invention. The invention, as described herein, is susceptible to various
 modifications and adaptations, and the same are intended to be
 comprehended within the meaning and range of equivalents of the appended
 claims.