US 3192853 A
Description (OCR text may contain errors)
4 Sheets-Sheet l NNN I. ILL
July 6, 1965 J. E. OCONNOR nocumnuw DISINTEGRATING mmnon Original Filed April 5, 1963 July 6, 1965 J. E. O'CONNOR 3,192,853
, DOCUMENT DISINTEGRATING METHOD Original Filed April 5, 1963 4 Sheets-Sheet 2 F" 1 if y 6, 1965 I. E. O'CONNOR 3,192,853
I DOCUMENT DISINTEGRATING METHOD Original Filed April 5, 1963 4 Sheets-Sheet 3 206 209 0 \O Q I, II 24! Q Q i 212 214 M/1 6/V 70A 214 J2me: 6 OJwmer July 6, 1965 J. E. OCONNOR vocumnn'r DISINTEGRATING METHOD Original Filed April 5, 1965 4 Sheets-Sheet 4 United States Patent 'Original application Apr. 5, 1963, Ser. No. 285,162.
Divided and this application Nov. 27, 1964, Ser. No. 414,328 5 Claims. (Cl. 10039) This application is a division of copending application Serial No. 285,162, filed April 5, 1963, entitled Document Disintegrating Mechanism.
The present invention relates to disposal methods, and it relates more particularly to an improved method for destroying, disintegrating and disposing of classified documents and similar material, after the material has served its intended purpose.
It is usual in the United States, and in other countries, to classify all documents, books, reports, proposals, drawings, or other material afiecting the defense of the country. This material has several degrees of classification ranging, for example, from confidentia to top secret.
The destruction of classified material once it has served its purpose has long presented a serious security problem. It is evident that, in each instance, every precaution must be made to assure that the particular document to be destroyed is, in fact, destroyed, and that the document does not fall into the hands of unauthorized persons. It is also evident that practical economics presents a serious factor in providing adequate supervision by security oflicers, especially where large quantities of classified material are to be destroyed on a daily basis, as is the case in many of the larger defense facilities and in the plants of the larger firms with extensive government contracts.
A usual procedure in the past has been to burn the classified material to be destroyed. This has involved, however, elaborate systems for gathering the material, taking the material to a central burning point, and supervising the burning of the material.
The operations involved in providing for the routine burning of classified material have proven to be most expensive in that they require a relatively large number of security ofiicers for relatively long periods of time. Also, ditliculties have been encountered in providing suitable central burning plants which are capable of adequately performing their intended function without creating a smoke nuisance in the surrounding neighborhood.
Because of the difficulties encountered in burning classified material which is to be destroyed, the Department of Defense has recently authorized other procedures for the destruction of classified documents. These latter procedures involve either pulping the material, or milling the material by hammer mill mechanisms. 7
The pulping procedures have -proven to be relatively slow and cumbersome. These procedures involve feeding the classified papers into a large vat and mixing them 3 with water until they are formed into an undistinguishable pulp. As noted, the pulping procedures are relatively slow, and require close and lengthy supervision to assure that all the papers fed into the pulping vat are fully and completely destroyed.
The milling procedure appears to be the most feasible. However, this procedure also in the past has created problems in that complicated security measures were previously considered necessary to supervise the feeding of the papers into the milling mechanism, and of assuring that the papers are fully and completely destroyed in the mechanism.
An object of the present invention is to provide a method for destroying and disposing of classified material by mechanical means, which method operates on a closed ice system principle so as to require a minimum of security supervision, and by which the violation of security or the unauthorized removal of the documents from the mechanism is positively prevented. 7
Another object is to provide such an improved method which absolutely assures that all documents will be completely destroyed.
In the practice of the invention, as exemplified in the embodiment to be described, the disposal apparatus is mounted on a trailer truck to be transported, for example, from plant to plant, and from point to point within a plant.
The apparatus is constructed to receive, for example, locked wheeled bins which have slots to receive the classified material at originating locations. These bins are normally positioned at diiferent points in the particular plant, and are chain locked, for example, to appropriate posts, or the like, at these areas to prevent their unauthorized re moval.
When the bins are so positioned around the plant, all classified documents to be destroyed may be deposited in them through appropriate slots. The mobile unit incorporating the apparatus to be described then makes scheduled visits to the plant. Prior to such a scheduled visit, a security officer removes all the bins from their normal points and wheels them, still locked, to a chosen area. This chosen area, for example, may be just within the gates of the plant, so that the gate guard may be charged with the duty of supervising the destruction of the classified documents. It will be appreciated as the present description proceeds, that a single security oflicer is capable of wheeling all the locked bins to the chosen area, and the intermittent attention only of the gate guard is required in the actual destruction of the material.
Upon the arrival of the mobile unit incorporating the the apparatus. The gate guard then unlocks the cover of the particular bin, without removing the bin from its enclosed locked feeding position. After unlocking the cover of the bin, the gate guard can return to his normal duties. When the cover of the bin is unlocked, it opens and the material in the bin flows down a closed conduit in the apparatus to be completely destroyed. When the destruction process is completed, the gate guard returns to unlock the empty bin from the apparatus, and to supervise the movement of a second locked bin into position on the apparatus, in the manner described above.
As will become more evident as the description proceeds, the entire destruction of the classified material of a large plant may be carried out under the supervision of a first security officer Whose duties involve moving the bins to the chosen area, and under the intermittent supervision of the gate guard whose duty involves unlocking.
the bins on the apparatus, and subsequently unlocking the unloaded bins from the apparatus.
An important feature of the process of the present invention, therefore, is the saving in time and numbers of security officers. This saving is realized by the fact that once a document is inserted into one of the bins referred to above, the document follows a path to its ultimate destruction which is completely enclosed and which is not susceptible to security violation.
Other features and advantages of the invention will become apparent from a consideration of the following specification in conjunction with the accompanying drawings, in which:
FIGURE 1 shows a mobile unit incorporating apparatus for practicing one embodiment of the method of the invention;
' FIGURE 2 is a fragmentary sectional view, substantially on the line 2-2 of FIGURE 1, and showing the .2 details of a helical outlet feeding mechanism included in the apparatus;
FIGURE 3 is a fragmentary perspective 'view of the apparatus of FIGURE 1, taken from the rear of the view of FIGURE 1 and showing a portion of the apparatus on a reduced scale;
FIGURE 4 is an end elevational view of the apparatus of FIGURE 1, but with one of the components of the apparatus of FIGURE I removed, for purposes of clarity;
FIGURE 5 is a fragmentary view showing the manner in which a bin containing classified material is held in place on top of the apparatus, so that its material may be fed into the apparatus to be destroyed;
FIGURE 6 is a fragmentary sectional view showing the details of the milling component of the apparatus;
FIGURE 7 is also a fragmentary sectional view, showing the manner in which the material isfed through a closed conduit and conveyor to the milling component of the apparatus;
FIGURE 8 is a top perspective view of a bin containing classified material, the bin being illustrated in its locked position, and ready to be elevated to the top of the apparatus of the invention;
FIGURE 9 is a fragmentary sectional view of a modified apparatus for practicing a further embodiment of the process of the invention; and
FIGURE 10 is a perspective view of other components of the modified apparatus of FIGURE 9.
As illustrated in FIGURE 1, for example, the apparatus disclosed herein is mounted on a trailer truck 10. The trailer truck has an additional trailer 12 coupled to it, and the trailer 12 supports a diesel, or other type of engine, 14 of usual construction.
The apparatus includes a milling mechanism 16 which is mounted on a pair of I-beams 18 and 20 on the bed of the trailer truck 13. The milling mechanism 16 may be a hammer mill of the type, for example, presently manufactured by the Williams Patent Crusher and Pulverizer Co., Inc. of St. Louis, Missouri.
The milling mechanism includes a rotor 29 which is mounted on a central shaft 22. The central shaft'22 is suitably journaled, and it is driven by the drive shaft 24 of the diesel engine 14. The shaft 24 is coupled to the shaft 22 by suitable couplings 26, as illustrated in FIG- URE 1.
The milling mechanism includes a conduit 28 which defines an inlet for the mechanism, through which the material to be destroyed is fed. The mechanism also includes a conduit 34) which defines the outlet from the milling mechanism, and through which the material from the mechanism is fed. A grate 32 (FIGURE 6) is positioned at the entrance of the outlet. This grate has an arcuate configuration, as shown in FIGURE 6, and it is formed of a series of parallel grate bars which are positioned to define predetermined openings between each adjacent bar.
The rotor 20 of the milling mechanism includes a plurality of hammers, or Crushers, 34. These hammers are pivotally mounted on the rotor 20 by means of corre- The drive shaft 22 also drives a fan 50 (FIGURE 1).
The fan 50 may be of any suitable construction, and it is mounted at one end of the milling mechanism 16. The fan serves to draw air in through an inlet formed by a conduit 52 and past the outlet formed by the conduit 30 (FIGURE 7) to an outlet tube 54. The fan serves to draw the material through the conduit 36 from the milling mechanism 16 and to feed the material into a tank 4 56. The tank 56 is mounted on the forward end of the bed of the truck 16, as illustrated in FIGURE. 1.
The lower end of the tank 56 is coupled to an outlet tube 58 which, in turn, is integral with a tubular conveyor housing 6%). The conveyor housing 59 extends across the bed of the truck 10, and it, including a telescopic sleeve-like portion 62a, can be moved to an extended position, as shown by the broken lines in FIGURE 1. A helical conveyor 62 is mounted in the housing 60, as shown in FIGURE 2. The conveyor 62 is driven by the drive shaft 22 through a suitable coupling, not shown. As shown in FIGURE 2, the helical conveyor 62 is tapered, and this conveyor serves to compress the fluffy material from the tank 56, and to force the compressed material out through the end of the extended tube 6%. The resulting material may be loaded into any appropriate vehicle, such as the cart 64. A suitable clutch mechanism may be included in the coupling between the shaft 22 and the conveyor 62, so that the conveyor 62 is driven only when it is desired to unload the material in the tank 56.
The illustrated apparatus also utilizes a vibratory feeder 79 which is mounted on posts 72 on the bed of the truck 10. The vibratory feeder 7%? includes a trough 74 which has an open top for receiving material, and which discharges the material from its left hand end in FIGURE 7. The left hand end of the trough 74 is coupled by a conduit 76 to the inlet, defined by the conduit 28, of the milling mechanism 16.
A hopper 80 is mounted on the upper end of the trough 74. As best shown in FIGURES 1, 4 and 7, this hopper has a rectangular configuration in cross-section, and it has walls which slope inwardly from the top to the bottom.
The trough 74 maybe inclined slightly towards the conduit 76, and the trough is driven by a suitable drive mechanism 86. The drive mechanism 86 produces a vibratory rectilinear movement to the trough 74 in a direction to the left and right in FIGURE 7. The vibratory conveyor or feeder 70 may be of the type manufactured and sold by the General Kinematics Corp. of Barrington, Illinois.
The classified material to be destroyed by the mechanism is deposited in a bin (FIGURE 8). This bin, and others like it, as described above, are placed in different positions around the particular plant. The classified material to be ultimately destroyed is deposited in the bins through a slot 162. The slot 1R2, as shown in FIGURE 8, is formed in one of two hinged covers 104 and 106.
The bin 109 is held locked by means of a bar 163 which extends through a pair of brackets 110 and 1.12 and which is held in place by a padlock 114. The padlock 114 may be a usual security approved padlock, and can be unlocked only by a qualified security officer.
A pair of channels 115 and 118 are mounted on the bottom of the bin 1%, and these channels receive the forks 120 of a hydraulic lift 122. This lift may have any usual and known construction, and it is mounted adjacent one side of the milling mechanism 16.
' The hydraulic lift 122 includes a pair of guides 124 which support respective movable chains. The movable chains are driven by controlled hydraulic means to move the forks 12% from a lower position shown in FIGURE 4 to an upper position shown in FIGURE 1. The guides 124 are shaped to have an upper arcuate configuration, so that the lift 122 is capable of lifting the bin 108 from the position shown in FIGURES 3 and 4 up to the position shown in FIGURE '1.
When the bin 1% is in the position shown in FIGURE 1, it is held in an inverted position over the top of the hopper 8G. The hopper 89 includes a notch 15% (FIG- URES l and 7) which receives the end of the locking bar 108, so that the padlock 114 is positioned outside of the 75 hopper 80. V
' The security officer may now unlock the padlock 114 and remove the bar 103. When the bar 168 is removed, a spring-loaded plunger 152 on the hopper 8t enters into the bracket 11% of the bin 19, as shown in FIGURE 7. This plunger may be locked in place by a padlock 154. The padlock 154 may also be a security padlock, and it is locked in place by the security otlicer after he unlocks the padlock 114 and removes the bar 108. The locked plunger 152 serves to lock the bin in its inverted position over the hopper 80.
When the bin is in its inverted position, and after the bar 168 has been removed, the cover members 104 and 1&6 open downwardly, as shown in FIGURE 7. This permits the material in the bin 16% to drop down into the trough 74 of the vibratory feeder 70. It will be appreciated that the system is entirely closed and locked. That is, the bin 100 remains locked by the padlock 114and locking bar 1118 until it is in position over the top of the feeder 81 Then, the unlocking of the padlock 114 and removal of the bar 168 permits the bin 100 to open into an enclosed housing which is inaccessiblefrom the exterior. Also, the locking of the padlock 154 causes the bin 1% to be securely locked on the hopper 80.
A glass covered inspection window 160 (FIGURE 7) may be provided in the side of the hopper 80 to enable the security oflicer to determine Whether or not the material in the mechanism has been in fact completely destroyed. This inspection Window may be normally covered by a door 162 (FIGURE 1), which is normally locked closed by a security padlock. The door 1&2 may be opened only by a security ofiicer, to permit the desired visual inspection. Other similar windows may be provided at other parts of the apparatus, such as in the side of the actual milling mechanism 16 itself.
As described above, in the practice of the invention, the mobile unit of FIGURE 1 makes a scheduled stop at a particular plant. Prior to this scheduled stop, a plurality of bins, such as the bin 1% of FIGURE 8, are gathered by a security ofiicer and brought to a designated area. As noted, this designated area may be just inside the main gate of the plant, and under the observation of the gate guard. The mobile unit then enters the gate, and the bins 199 are successively lifted into position so that their contents may be loaded into the apparatus.
As each bin is lifted into the position of FIGURE 1, the gate guard unlocks the padlock 114 and removes the locking bar 168. Then he looks the padlock 154 to assure that the bin 1% is locked in place on top of the hopper 89. The mechanism is then started, and the material in the bin 1% is completely pulverized and fed to the tank 56. At the completion of the operation, the gate guard is signalled, and he makes a visual inspection through the windowlofi. I-Ie then unlocks the padlock .154, and the empty bin 1% is removed. The procedure in then repeated for each successive bin.
At the completion of the operation, the mobile unit It) may depart'for the next plant. Whenever the tank 55 becomes full, it may be unloaded in the described manner into any suitable conveyor, such as the vehicle 64.
The apparatus shown in FIGURES- 9 and 10 also utilizes many of the components described above, and such components are not, for the most part, repeated in FIGURES 9 and 10. As will be described, the latter apparatus may be loaded in the manner described above in conjunction with the apparatus of FIGURES 1-8.
The apparatus shown in FIGURES 9 and 10 includes a pair of milling mechanisms 20!) and 2&2 which are,
mounted on top of one another, as shown in FIGURE 9. The milling mechanism 2% is relatively large and it may be designated asthe primary mill; whereas the milling mechanism 262 is relatively small, and it may be designated as the secondary mill. These milling mechanisms may be of the above-described hammer mill type manufactured by the above-mentioned Williams Com pany.
r The purpose of the provision of two milling mechanisms in'the apparatus of FIGURES 9 and 10 is to enable the apparatus to handle material of all shapes and sizes, and which normally would have a tendency to plug the secondary mill. The primary mill 2G6 acts on the incoming material and reduces it to a size which can be conveniently handled by the secondary mill 202. The secondary mill then acts on the material from the primary mill and reduces it to the final desired flutfy constituency.
The primary mill 200 includes a rotor 264 which is mounted on a control shaft 206. The control shaft 206 is suitably journalled, and it is driven by an appropriate drive engine, like the diesel engine 14 of FIGURE 1.
The control shaft 206 serves to drive the rotor 2614 in a clockwise direction insofar as the View of FIGURE 9 is concerned.
' A conduit 207 defines the inlet mouth to the primary milling mechanism 200. An inspection door 209 may be mounted in the conduit 207. A grating 268 is interposed between the outlet of the primary mill 2% and the inlet of the secondary mill 202, and this grating determines the size of the material to be fed from the primary mill into the secondary mill.
The secondary milling mechanism 202 includes a rotor 210 which is mounted on a drive shaft 212. The drive shaft 212 is driven, togethe with the drive shaft 296, from a suitable drive engine, such as the diesel engine 14 referred to above. The rotor 210 is also driven in a clockwise direction as seen in the view in FIGURE 9.
The outlet of the secondary miling mechanism 202 is coupled to an outlet conduit 214 which, in turn, is coupled to a feed-line 216 (FIGURE 10). A screen 213 is positioned across the outlet of the secondary mill to determine the constituency of the flufiy material fed to the outlet conduit 214.
The'feed-line 216 extends to a separate unit 218 (FIG- URE- 10) which is in the form of a large housing mounted on a wheeled trailer, for example, and which will be described in detail subsequently. In the practice of the second embodiment of the invention, the mechanism of FIGURE 9 and the drive engine are both mounted on a truck, such as shownin FIGURE 1, and the trailer of FIGURE 10 is coupled behind the truck so as to provide mobility for the equipment.
The mechanism of FIGURES 9 and 10 also includes a fan 217 which is interposed in the feed-line 21%, and which may be similar to the fan described above in conjunction with the previous embodiment. This fanserves to draw the-material through the primary and secondary mills 260 and 292, and to discharge the resulting fluffy material through the feed-line 216 into the housing 218. The fan 217 isdrivenby a separate motor 219. This motor may, for example, be a four cylinder gasoline engine of about 42 horsepower. A clutch, not shown, may also be provided so as to control the flow of fiufi through the line 216. The motor 219 drives the fan 217 'at, for example, 2109 r.p.m., and the mills are driven at, for example, 1950 r.p.m., so as to assure ample flow of air. This separate and independent drive of the tan is advantageous in that when the main diesel is caused to lose speed in the presence of large loads dumped into the mechanism, the air flow through the mills does not drop also but continues at a relatively high rate.
An open-ended chute, or hopper, 220 is mounted on top of the primary milling mechanism 200 and over the inlet conduit 207 of that mechanism. Theupper end of the chute 220 has a pair of doors 224 and 226. These doors are hinged to the sides of the chute and, when closed, extend across the top of the chute to close the chute. The doors arehinged so that they may open downwardly, as shown in FIGURE 9. a
The doors 224 and 226 are hydraulically controlled by suitable hydraulic mechanisms, such as the mechanism 228 shown in FIGURE 9. Each door may be individually opened or closed by the actuation of its hydraulic .without clogging the entrance.
'5" mechanism. This actuation may be controlled, for example, by a pair of hand levers 239, 232' (FIGURE A bin, such as the bin 190, may be placed, top down, over the top of the chute 220. This placement of the bin in position over the top of the chute 220 may be carried out by a mechanism similar to the elevator mechanism illustrated in the previous embodiment and described in conjunction therewith.
However, in the apparatus of FIGURES 9 and 10, when the doors of the bin are unlocked by the security ofiicer, they are not free to open, as in the previous embodiment. Instead, the doors of the bin are held closed by the doors 224 and 226. The actuation of the doors 224 and 226 provides a control for the feed of the material from the bin into the apparatus.
The apparatus of FIGURES 9 and 10 is advantageous in that it is capable of handling loads from the bins 10$ quickly and efiiciently, and without any likelihood of jamming the mills due to sudden excessive loads. Durthe operation of the apparatus, whenever the speed of the mills drops below a particular threshold, thereby indicating an excessive load of material in the mills, the hand levers 230 or 232' can be operated to close the doors 224 and 226 and thereby close the doors of the bins. This serves to reduce, or cut off, the loading of the apparatus until the work in process has been passed to the outlet, as indicated by the restoration of the normal speed of the mills.
As mentioned above, the provision of the large primary milling mechanism 200 and of the smaller secondary milling mechanism 202 enables the apparatus shown in FIG- URES 9 and 10 to handle a Wide variety of loads from the bin 2% without clogging or jamming. These loads may include, for example, thick books, stapled stacks of paper or blueprints, and so on. This flexibility in the handling capabilities of the latter embodiment are most desirable because security reasons prohibit the operator from examining the contentsof any particular bin before such contents are fed into the apparatus.
The large area direct channel openings through the chute 22G directly into the mouth of the primary mill 200 assure that large pieces of material will be fed to the mill Then, and as mentioned above, the primary mill grinds the material fed to it into smaller pieces which are fed to the secondary mill which, in turn, reduces them to the desired fiutfy constituency.
The illustrated apparatus of FIGURES 9 and 10 is capable, therefore, of handling material of a large range of shapes and sizes. As mentioned, the primary milling mechanism 2% mills all the material down to a size which will pass through the grating 208. This reduces the material to the capabilities of the secondary mill 202. The
secondary mill then mills the pieces from the primary mill down to a fluffy constituency which may be drawn by the fan down through the screen 213 and into the conduit 214.
As mentioned, the flufiy material from the secondary mill 262 is then blown through the feed-line216 into the interior of the housing 218. As also mentioned, the housing 218 is mounted on wheels 221, so as to constitute a trailer which may be coupled onto the back of the truck supporting the apparatus of FIGURE 9. A fragmentary.
portion 222 of the truck is shown, for example, in FIG- URE 10.
As illustrated, the housing 218 has a large rectangular V configuration. The flufiy material from the feed-line 216 is blown into the housing through aperture 225 in the roof of the housing. The fluffy material so blown into the housing has a tendency to drift back towardsthe rear. The air stream passes through an outlet port 227 and through a pair of feed-lines 229 into a pair of porous collapsible filter dust bags 230. The dust bags 230 may be removed from time to time for cleaning purposes. These dust bags serve to prevent fine dust from settling around the adjacent territory during the operation of the apparatus.
The trailer also includes a Water tank 232 which is mounted under the housing 218. An associated pump 234 pumps water from the tank 232 up through an exterior water line 236 and into an interior sprinkling system 239. The interior sprinkling system causes water to be sprayed in the interior of the housing 218 to settle the dust, and this serves to eliminate any danger of explosion.
A hydraulically operated blade 238 is mounted within the housing 21S, and it extends across the interior of the housing. The blade 238 is movable from the left-hand end of the housing to the right-hand end by an appropriate hydraulic ram 240. The ram is operated by suitable controls.
From time to time during the operation of the apparatus, and after a predetermined number of loads, for example, the loading of the flufify material into the housing 218 is discontinued fora time, and the blade 238 is operated by the ram 240 to compress the fluffy material already in the housing. During this operation, the blade 238 is moved by the ram 24-43 from the left-hand end of the housing 218 to the right-hand end of the housing and the material is compressed against the back of the housing. The blade is then returned to the left-hand end of the housing, and the next load of fiutiy material is blown into the housing. This operation is continued until the housing 218 is filled with compressed fiufiy material.
A pair of hinged doors 242 are provided on the back of the housing 218. To unload the housing, it is merely necessary to open the doors 242, and then to cause the .ram 240 to move the blade 238 towards the open back of the housing. This action causes the compressed material to be discharged out the open back.
An inspection door 244 may be provided in the side of the housing. This inspection door is positioned, for example, towards the left-hand end of the housing.
The invention provides, therefore, an improved process for destroying classified material. As described above, the process of the invention operates on the basis of an entirely closed system, so that the requirement for security personnel is reduced to a minimum, and the entire operation may be supervised, for example, by a single security oificer. Moreover, the presence of the security officer is not required continuously, but only when a new bin is to be fed into the mechanism.
While particular embodiments of the process of the invention have been shown and described, modifications may be made. It is intended in the following claims to cover all the modifications which fall within the spirit and scope of the invention.
What is claimed is:
1. A method of accumulating and destroying documents including: collecting the documents in locked receptacles at predetermined locations in a particular area; moving the filled receptacles to a common documentdestroying station for discharge into a document-destroying mechanism; and locking the receptacles to said document-destroying mechanism during the discharge of the documents into said mechanism.
2. A method of accumulating and destroying docu ments including: collecting the documents in locked receptacles at predetermined locations in a particular area; moving the filled receptacles to a common documentdestroying station for discharge into a document-destroying mechanism; locking each receptacle to said documentdestroying mechanism; and opening each receptacle as it is so locked to the mechanism so as to permit its contents to be discharged into the mechanism.
3. A method of accumulating and destroying documents including: collecting the documents in receptacles having locked doors thereon and positioned at predetermined locations in a particular area; moving the filled receptacles to a common document-destroying station for discharge into a document-destroying mechanism; inverting each receptacle over the document-destroying mechanism in a locked relationship with the mechanism; and
unlocking the doors of the receptacle inverted over the mechanism to permit the contents thereof to be discharged into said mechanism.
4. A method of accumulating and destroying documents including: collecting the documents in receptacles having locked doors thereon and positioned at predetermined 1ocations in a particular area; moving the filled receptacles to a common document-destroying station for discharge into a document-destroying mechanism; inverting each receptacle over the document-destroying mechanism in a locked relationship with the mechanism; unlocking the doors of each receptacle inverted over the mechanism to permit the contents thereof to be discharged into the mechanism; milling the documents discharged into the mechanism in a plurality of successive steps in the mechanism; pneumatically conveying the milled material from the mechanism to a press; and compressing the milled material in the press. a
5. The method defined in claim 4 and which includes the steps of liquid spraying thematerial in the press; and
collecting dust from the press in a separate filter means,
References Cited by the Examiner UNITED STATES PATENTS Erlinder et al 214-302 WALTER A. SCHEEL, Primary Examiner.
BILLY I WILHITE, Examiner.