US2421938A

US2421938A - Materials sampler

Info

Publication number: US2421938A
Application number: US540157A
Authority: US
Inventors: Thomas R Held
Original assignee: ADAMSON STEPHENS Manufacturing CO
Current assignee: ADAMSON STEPHENS Manufacturing CO; STEPHENS-ADAMSON Manufacturing Co
Priority date: 1944-06-13
Filing date: 1944-06-13
Publication date: 1947-06-10
Anticipated expiration: 1964-06-10

Description

June 10, 1947. T, k, HEL 2,421,938 MATERIALS SAMPLER Filed June 15, 1944 s sheets-sheet 1 INVENTOk 172077205 f2 Held, BY

June 10, 1947. r. R. HELD I MATERIALS SAMPLER I Filed June 15, 1944 3 Sheets-Sheet 3 I I l l I l L INVENTOR. flzamaalificl BY Patented June 10, 1947 ,l "Thomas Held, Aurora; Illl,

Stephens-Adamson Mfg. (30., a corporation of Illinois assignor. to

Application June 13, 1944, Serial No. 540,157

5 Claims. (01. 73-423) My invention relates to devices employed with various types ofconveying or feeding apparatus to obtain representative samples from streams of materials, such as coal, ore, cement, lime, sand and the like. The invention may be applied to various apparatus including belt conveyors, screw conveyors, bucket elevators, feeders cyclone collectors, hoppers, etc. I elect, by way of example, to describe the invention as employed for collecting sample portions from a stream of material falling from a belt conveyor, such disclosure being adequate guidance for other specific applications of the principles involved.

A sampler of the present type consists essentially of a sample collector, such as a-spoon or small hopper of small cross section together with means to reciprocate the collector across the material stream in a uniform manner thus to obtain a material sample corresponding in character to the material of the stream as a whole.

The general object, of my invention is to provide an improved actuatingarrangement for reciprocating the sample collector. Heretofore actuating arrangements for this purpose have commonly been motor driven mechanisms in which all the moving parts including the motor and the associated speed-reducing means are reversed for each traverse of the collector. Certain disadvantages'are inherent in such an arrangement.

In the first place, since all of the moving parts must be reversed for each traverse, considerable inertia must be overcome at the end of each traverse, Braking devicesshock absorbers and similar expedients that are used must dissipate considerable energy as the; moving parts reach their limit positions and failure ofsuch deceleration expedients to function results in damage to the mechanism. 7 v i In the second place, limit switches are required to de-energize or reverse the drive motor at both of the limit positions of the sample collector. The sample collector tends to coast beyond its limit switches and the failure of a limit switch to function properly inevitably has damaging consequences.

In. the third place, reversing the motor for each traverse of the sample collector involves not only breaking the motor circuit at the end of each traverse but also subjecting the motor and any associated. drive shaft to peak torque at the end of each traverse.

In contrast to such prior ,art'arrangements, I propose to provide a driving arrangement in which the actuatin motor andcertain associated mechanism operate unidirectionallyv during reciprocation of the sample collector so that only the sample collector and elements intimately associated therewith need be reversed in movement, Since the motor and other parts of the driving mechanism need not be reversed for each traverse of the sample collectoninertia at the endof atraverse createsno great difliculty and requires no special expedient for avoiding structural damage. Since/the motor need not be deenergized or reversed at the end of each traverse, limit switches withsattendant disadvantages may be omitted. A stop switch may be employed for automatic control but the failure of such a stop switch to function need involve no hazard to the mechanism.

Afurther object of my invention is to provide an effective arrangement for protecting the driving mechanism from the material being sampled; an object of special importancewhen the material includes considerable dust particles hard enough to lie-abrasive.

, In general, these objects are attained by actuating the sample collector through the medium of areversely threaded shaft whereby the shaft and the motor for actuating the shaft may operate unidirectionally, the sample collector being controlled: by the equivalent of atraveling nut engaged by the reversely threaded shaft: In the preferred practice of my invention, the shaft and the traveling nut in engagementwith the reversible thread of the shaft are housed in a transmission chamber and are sealed off from the material stream in a dust-proof manner. The above and other objects and advantages of my invention will be apparent from the following detailed description taken with the accompanying drawings.

In the drawings, which are to be regarded as merely illustrative, Fig. 1 is a perspective view of a conveyor equipped with the preferred form of' my invention, i i i Fig. 2 is a perspective viewof the sample collector and associated mechanism,

, Fig; 3 is an enlarged fragmentary view of a portion of the reversely threaded shaft of Fig. 2,

Fig. 4 is a horizontal section through the conveyor taken at the level indicated by the line 4 in Fig. 1, the view showing the principal parts of the invention in plan,

Fig. 5 ,is a sectiontaken along the line 5-501, Fig.4, Figs. 6 and 1am enlarged sections talren as indicated by the lines 6- -5 and l- -l in Fig. 5,

. or spoon I2 of stainless steel or other suitable material is mounted in the main chute I I to reciprocate across the stream S and is illustrated in the form of a narrow hopper with an inclined lower spout I3 for discharging the collected material into a sample chute I5 branching from themain chute. In the well known manner, the sample chute I5 leads to a sampler container (not shown), the contents of which are examined or tested from time to time to ascertain the character of the material passing down the main chute II.

Preferably the main chute I I is locally enlarged in cross section to provide sheltered spaces or pockets within the main chute into which the collector I2 may move at each end of its reciprocation across the chute. Thus each side of the enlarged portion of the main chute II- has overhanging walls I6 under which the collector may be positioned out of range of the falling stream of material. One reason for providing such sheltered pockets is to permit movement of the collector to an idle or inoperative position and another reason is to achieve uniformity in the samples collected. Causing the collector to pause and reverse its movement while receiving material at the side portions of the streams would result in drawing an undue proportion of the sample from the side portions of the stream.

One end of the collector I2 is shown provided with a bracket I! in which is journaled a supporting roller I8 to traverse a suitable track 20. Extending from the other end of the collector is a bar 2| having the dual functionpf supporting the collector and transmitting reciprocating motion to the collector.

The means for actuating and controlling the movements of the collector t2 includes a transverse shaft 22 journaled in suitable bearings 23 on the-exterior of the main chute I I and a motor 25 that drives the shaft'through-the medium of a belt 26 and sheave 21. In the present practice of the invention, the major central portion'of the transverse shaft 22 is in a housing or transmission chamber 28" that is mounted on the outside of the main chute II, there being a transverse opening or window 30 for communication between the :transmission chamber and the interior of the main chute. Preferably the shaft22 runs in an oil bath.

The transverse drive shaft 22 is reversely threaded, that is to say is provided with a continuous thread having a left traverse portion and aqright traverse portionwith the corresponding ends of the two traverse portions interconnected by transition portions. Such a thread may be either in the form of a rib or a groove. Thus Fig. 3 shows a groove type thread, the figure indicating the manner .in which .a transition portion 3| interconnects a left traverse portion 32 and a right traverse portion 33.

Slidingly mounted on the driving shaft 22 is a traveling member or traveling nut '35 to which is fixedly attached the end of the previously mentioned support bar 2I for the collector I2. Any suitable provision may be made for engaging the traveling member 35 with t e revers n thread of the drive shaft.

driving thread on the shaft 22.

In the preferred practice of my invention, I mount in the traveling member a suitable dog 36 for this purpose. The dog 36 has a cylindrical body 37 that is rotatably journaled in a bore 38 and is provided with a circumferential groove 40 for engagement by a set screw 44, the set screw preventing axial movement of the dog while permitting freedomfor rotation. Extending inwardly from the body 31 of the dog is an integral tooth 4| for continuous engagement with the Preferably the end of the tooth II is suitably curved in profile for effective engagement with the shaft thread for a substantial dimension lengthwise of the thread.

Preferably yielding means is provided to resist movement of the collector I2 as the dog 36 reaches one of the transition portions (H of the continuous thread, the purpose of such yielding means being not merely to assist in decelerating the movement of the collector but also to assist in reversing the direction of the collector movement; thus to avoid undue strain on the dog as the tooth of the dog passes through one of the transition portions ill of the reversing thread. For this purpose I may provide two coil springs fleencircling the threaded shaft 22, each of these springs being positioned for compression between the traveling nut 35 and the end wall of the transmission chamber as the traveling nut approaches its two limit positions.

The provision for sealing off the interior of th transmission chamber 28 from the interior of the main chute II may include, for example, a sealing plate 62 to span the transverse Wall opening 30, the sealing plate being provided with a suitable transverse slot 43 to clear the support bar 2|. Suitable resilient means such as a pair of rubber strips 45 mounted on the sealing plate 42 on opposite sides of the slot 43 normally contact each other, as shown in Fig. 5, to function as a pair of sealing lips for closing the slot. The support bar 2| extending between the two cooperating lips .parts the lips to format each side of the bar a small triangular opening 36 that travels with the bar. See Fig. 6. I t

In the preferred practice of my invention, I provide a slide member 41 with a central opening to receive the support bar 2I, the slide member having a pair of set screws 48 for fixedly connecting the slide member with the support bar. The slide member 41 is formed with an elongated boss 50 for sliding engagement with the edges of the slot 43. Such a slide member has two functions. In the first place, the face of the elongated boss 50 serves as a traveling closure for the two traveling openings 46. In the second place, the boss in engaging the edges of the slot 43 supports the support bar 2I, and, if desired, may be so effective in this function as to prevent any substantial weight being imposed on the traveling nut 35.

In the present practice, means is provided to cause the collector I2 to pause automatically for predetermined time periods at one of its two limit positions. As indicated in Fig. 4, such means may include a stop, switch or limit switch 5I on the outer wall of the main conveyor'chute II and a short shaft 52 extending through the conveyor wall, there being an arm 53 on the inner end of the shaft for actuation by the collector I2 and an arm 55 on the outer end of the shaft for operating the switch 5I.

A suggested wiring diagram that may be used in practicing the invention is shown in Fig. 9.

The diagram, which requires no detailed description, includes the following elements: a motor starter 56, having the commercial designation CR7006-D50-B; a push button 51, commercial designation, CR2940-1A2; the above mentioned limit switch commercial designation, GHQ i40- D2DD; a timer 58, commercial designation, CR2820-1099P; and a time delay relay 65], commercial designation CR2820-l731A.

The limit switch 5| has a :pair of normally closed contacts and a pair of normally open contacts. When the collector l2 depresses the inner arm' 53' and thereby actuates the limit switch 5|, the normally closed contacts of the switch open and the normally open contacts of the switch close, the closing of the motor circuit, however, being delayed by the timer 58.

The manner in which the described embodiment of the invention operates may be readily understood from the foregoing. In the course of usual operation, the collector l2 traverses left to right, as viewed in Fig. 4, reverses automatically to traverse right to left and then upon depressing the switch-control arm 53 comes to rest in the left-hand pocket for a time period determined by the setting of the timer 58.

The push button switch 51 provides both a start button and a control adjustable to either a run position or a safe-stop position, the latter position precluding operation. At the begin' ning of an operating day the start button may be used to initiate movement of the collector I2 without time delay, or, if desired, the adjustable control may be shifted from its safe-stop position to its run position to have the timer run for a predetermined period before the collector operates. The time delay relay 66 operates only after the start button is depressed thereby making a holding circuit to cause the collector to operate untli such time as the limit switch 5| is returned to its normal position to make a holding circuit.

When the collector H be under the protection avoid collecting material. If the collector is in motion and it is desired to stop the sampling operation, it is necessary merely to shift the adjustable control to the "safe-stop position, whereupon the collector will reciprocation because there is a holding circuit through the limit switch and the collector will eventually come to a stop in the pocket to remain stationary indefinitely.

An important feature of the present arrangeis stationary, it should of the side pocket to ment is that the combination of the unidirectional driving means and the automatic reversing driving connection between the driving means and the collector l2 doubles the extent to which the collector may coast to a stop in a pocket of a given width. In other words ,after the motor is de-energized, the coasting of the moving parts may extend not only to the point at which the collector reaches its left limit position but may also continue while the collector coasts in the reverse direction so long as such continuation does not carry the collector into the stream of falling material. This feature is important because a relatively extensive coasting range permits the gradual deceleration of moving parts that is conducive to long service life and also a long coasting range permits satisfactory operation Without necessity for any special braking means or other expedient to decelerate the sampler mechanism.

The extent to which the collector l2 may coast continue its cycle of in its reverse direction without. leaving the shelter of the pocket may be appreciated by in"- specting Fig. 4. The right side of the sheltering pocket extends approximately to the line 6|, which line represents the normal inside width of the main conveyor. On entering the pocket, the collector l2 rides over the switch-controlling arm 53 at approximately the moment the collector clears the line GI and the arm 53 is depressed as long as the collector remains in the pocket. After the collector has coasted from the line El to the limit position shown in Fig. 4, itmay continue to coast in the opposite direction by the distance shown in Fig. 4 between the positionof the collector and the line 6!.

The preferred practice of my invention described in specific detail herein for the purpose of disclosure and to illustrate the principles involved will suggest to those skilled in the art various changes and substitutions under my basic concept and I reserve the right to all such departures from my description that properly lie within the scope of my appended claims.

1. Means in a conveyor to obtain representative samples from a stream of falling material in the collector to one side of said stream, a unidirectional driving means operatively connected with said collector to cause the collector to traverse said stream and enter said pocket, means to deenergize said driving means when said collector enters said pocket thereby to cause the driving means and the collector to coast to a stop, and means to reverse the operative connection between the driving means and the collector with respect to the direction of operation of the collector relative to the direction of operation of the driving means when the collector reaches a limit position in the pocket, whereby the collector may continue its coasting in the opposite direction, the width of the pocket being sufilcient to permit such reverse coasting of the collector to a full stop without exposure of the collector to said stream of material.

said pocket, cuit of said motor when said collector enters said pocket thereby to cause the driving means and the collector to coast to a stop, means to reverse the operative connection between the motor and of operation of the driving means when the collector reaches a limit position in the pocket, whereby the collector may continue its coasting in the opposite direction, the width of the pocket being sufficient resume movement in the direction of coasting.

3. In a. sampler for use in a stream of falling material, the combination of a collector to receive and separate sample portions from said stream,

a transmission chamber having a transverse slot communicating with the space occupied by said stream, resilient means tending to seal said slot, a drive screw in said chamber, a traveling nut engaging the thread of said screw, and means connecting said nut through said slot and past said resilient means to said collector to reciprocate said receiver across the stream in response to rotation of the shaft.

4. In a-sampler for use in a stream of falling material, the combination of a collector to receive and separate sample portions from said stream, a transmission chamber having a transverse slot communicating with the space occupied by said stream, resilient means tending to seal said slot, a drive screw in said chamber, a traveling nut engaging the thread of said screw, connecting means extending from said nut through said slot and resilient means to said collector to reciprocate the collector across the chute injresponsetorotation-of the shaft, said connecting means flexing said resilient means to form a small traveling opening in the resilient means adjacent the connecting means, and means carriedby said connecting means positioned to close said traveling opening.

, 5. In a sampler for use in a stream of falling material, the combination of a collector to receive and separate sample portions from said stream,

wall means forming a transmission chamber, said wall means'having a transverse slot communicating with the space occupied by said stream, resilient means normally sealing said slot, a drive screw in said chamber, a traveling nut in said chamber engaging said screw, connecting means extending from said nut through said slot and resilient means to said collector to reciprocate the collector across the chute in response to rotation of the shaft, said connecting means deforming said resilient means to form a small traveling opening in the resilient means adjacent the connecting means, and means carried by said connecting means for the dual purpose of closing said traveling opening and making supporting contact with said wall.

THOMAS R. HELD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,937,473 Geary et a1 Nov. 28, 1933 2,193,394 Deckert, Jr Mar. 12, 1940 2,352,204 Jordan June 27, 1944 1,399,107 Frankowski et a1 Dec. 6, 1921 1,723,189 Martin Aug. 6, 1929