Apparatus For Comminuting Trash

Abstract

In apparatus for comminuting trash in which two parallel disposed shafts, one having a degree of axial play and the other substantially no axial play, a motor, reduction gearing disposed between the motor and shafts through which the motor drives the shafts, a reversing device for driving the motor in different directions and a plurality of groups of disc-shaped blades disposed at regular intervals on each shaft and arranged such that the groups on one shaft engage in the interstices between the groups on the other shaft are provided. The inner distance between two adjacent groups on the shaft having substantially no axial play is equal to the degree of play plus the width of the group on the shaft having a degree of play. Each blade has at least one step region including a tongue with the surfaces which define the tongue forming an opening angle of the order of magnitude of 30.degree.. The step regions of the blades on each shaft are angularly offset with respect to one another.

Parent Case Text

This is a continuation-in-part of application Ser. No. 180,687, filed Sept. 15, 1971 now abandoned.

Description

BACKGROUND OF THE INVENTION

The present invention relates to an apparatus for comminuting trash such as bottles, borings, crates or the like. More particularly, the present invention relates to an apparatus for comminuting trash including a motor, reduction gearing connected with the motor, at least one shaft driven by the reduction gearing, blades fastened to the shaft, an inlet opening disposed above the blades and an outlet opening disposed below the blades for ingress of the trash and egress of the comminutant respectively.

A larger number of devices for comminuting trash are known. These, however, are specialized and do not possess the desired versatility since they do not process everything that accumulates in industrial operations such as the boring and grinding industry, in warehouses and retail businesses, etc. There are also a variety of automobile batteries, plastic containers, oil barrels, wooden crates, catalogs, television tubes, bottles, steel shavings resulting from boring and grinding, etc. which they cannot process and comminute. Moreover, known devices of this type require more operating experience from the operating personnel and more care than might be expected. Fruit crates, for example, must first be broken up before being inserted for comminution.

Such a device must be able to handle the problems of glass dust resulting from smashing bottles and the comminution of metal objects which wrap themselves around the shaft and jam the device instead of being comminuted by the blades.

SUMMARY OF THE INVENTION

It is, therefore, a general object of the present invention to provide an apparatus for comminuting trash such as bottles, borings, crates or the like.

It is a more particular object of the present invention to provide a comminuting apparatus which can be operated with practically no operational knowledge.

It is another particular object of the present invention to provide a comminuting apparatus which is compact in size and yet is sufficiently versatile to accomplish the comminution of a variety of items such as automobile batteries, plastic containers, oil barrels, trash accumulations in industrial operations such as the boring and grinding industry, etc.

It is yet another particular object of the present invention to provide a comminuting apparatus including a plurality of groups of disc-shaped blades mounted on a pair of driven shafts disposed parallel to each other with one shaft having a degree of axial play and the other shaft having substantially no axial play and with the inner distance between two adjacent groups on the shaft having substantially no axial play being equal to the degree of play plus the width of the group on the shaft having a degree of play.

It is still another particular object of the present invention to provide a comminuting apparatus including a reversing device which can be either time or torque dependent.

It is yet another particular object of the present invention to provide a comminuting apparatus including an improved blade design.

These and other objects are accomplished according to the present invention by the provision of an apparatus for comminuting trash including two parallel shafts with one of the shafts having a degree of axial play associated therewith and the other shaft having substantially no axial play associated therewith; a plurality of groups of discshaped blades disposed at regular intervals on each shaft, so that the blade groups of the one shaft mesh in the interstices between the blade groups of the other shaft, and so that the inner space between two adjacent groups on the shaft having substantially no axial play associated therewith is equal to the degree of play plus the width of the intermeshing blade group on the shaft having a degree of play associated therewith, and further so that the shafts move during operation in opposite rotational directions and at a slightly different speed; a motor; reduction gearing disposed between the motor and shafts through which the motor drives the shafts; a reversing device for driving the motor in different directions; and inlet opening disposed above the blade groups through which trash is supplied to the blade groups; and an outlet opening disposed below the blade groups through which the comminutant is removed.

As used herein, the terms "play" and "axial play" are used in their ordinary dictionary senses, namely, the degree of freedom and uncontrolled motion of a shaft journaled in its housing, i.e., in the case of axial play, to move or function freely within prescribed limits in either direction parallel to the axis of the shaft. This is to be distinguished from the controlled movement of one shaft relative to another.

The forward direction of rotation of the shafts is such that when viewing the blade groups through the inlet opening, the blades move toward one another. That is, if one were to view a point on a blade on each of the shafts, these points would appear to approach each other as the two shafts are caused to rotate in the opposite directions.

The blades have one or a plurality of step regions where they deviate from a larger diameter to a smaller diameter. The step regions include surfaces which define a tongue and generally sickle-shaped recesses. The tongues extend in one direction of rotation of the blade. The surfaces defining the tongue form an opening angle of the order of magnitude of 30.degree.. A retreating area of the step region disposed below the tongue and toward the smaller diameter can accommodate items of the dimensions of ordinary wine, beer, liquor bottles or bottle necks thereof. The blades are mounted on each shaft so that the step regions thereof are angularly offset against one another.

Because of the axial play, room is provided between the sides of the blades for the glass dust mentioned above. However, the axial play is still small enough so that no metal pieces can get stuck in the resulting gap which then, instead of being comminuted, would only be pulled through the apparatus whole. Because of the different number of revolutions (speeds) of the two shafts, the items to be comminuted are caused to rotate if required and as a result are chewed by the blades from different sides. The different speeds prevent sudden stresses and jamming of the apparatus. The reversing device also serves to prevent the apparatus from becoming jammed.

In one embodiment of the present invention the blades are provided with a hexagonal bore. These blades are then mounted on a shaft which has a hexagonal circumferential configuration. In this embodiment, a substantially improved torsion connection between the blades and shaft results. However, this blade configuration is expensive to fabricate because the bore can only be produced by means of removal of material and must be carefully and slowly machined. Hexagonal shafts are more easily fabricated and commercially available in a relatively large number of different dimensions. However, they are substantially more expensive than circular shafts which can be turned much more easily, for example.

In order to obtain a substantially improved torsion connection between shaft and blade which is much less expensive, which requires no removal operations, which permits precision work where necessary to be done at relatively low cost, and which finally permits the arrangement of the blades in such a manner that their cutting tongues are offset by any desirable angular relationship, such as, for example, angles of 180.degree., 120.degree., 90.degree. etc., other embodiments of the blades and shafts are possible. For example, the blades are provided with a cylindrical bore, with recesses provided parallel to the bore at regular angular spacings. The inner surfaces of the recesses follow a circular arc. The shaft has a cylindrical circumference and fits into the blade bore. The shaft has at least one longitudinal groove parallel to its longitudinal axis whose inner surface complements the inner surface of one of the recesses in the blade, so that together they define a cylindrical bore. A cylindrical rod is fitted into the cylindrical bore defined by the shaft groove and blade recess.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the apparatus of the present invention to scale.

FIG. 2 is a sectional view taken along 2--2 of FIG. 1, to scale, but without motor, reversing device, fill funnel and feet.

FIG. 3 is a sectional view taken along line 3--3 of FIG. 2, showing the blade groups on one of the shafts as well as part of the gearing.

FIG. 3a is a vertical sectional view of the gear box showing the two shafts and the meshing gearing to drive each shaft.

FIG. 4 is a sectional view, to scale taken along the line 4--4 of FIG. 2, showing the other shaft as well as part of the gearing associated therewith.

FIG. 5 is a full scale side view of a blade according to one embodiment of the invention showing the stepped region thereof.

FIG. 6 is a view of FIG. 5 as seen in the direction indicated by arrow A.

FIG. 7 is a side view of a mounted blade according to another embodiment of the invention showing the stepped region thereof.

FIG. 8 is a view of FIG. 7 as seen in the direction indicated by the arrow C.

FIG. 9 is a side view of a blade according to a further embodiment of the invention showing three stepped regions.

FIG. 10 is a view of FIG. 9 as seen in the direction indicated by arrow D.

FIG. 11 is a schematic representation of the angular offset of the stepped regions of two successively mounted blade groups.

FIG. 12 is a schematic partial view as seen in the direction indicated by the arrow B of FIG. 3.

FIG. 13 is a schematic circuit diagram of one embodiment showing the reversing capability for the drive motor.

FIG. 14 is a sectional view comparable to the sectional view according to FIG. 3, showing the blade groups on one of the shafts and part of the gearing according to another embodiment of the invention.

FIG. 15 is a sectional view for the embodiment of FIG. 14 which is the same as the sectional view according to FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The apparatus according to the present invention is supported on four legs 11, as shown in FIG. 1. The legs 11 support a hopper or basket 12 or the like, into which the trash to be comminuted is placed through an inlet opening 12'; a 7.5 HP electric motor 13, whose shaft is perpendicularly disposed with respect to inlet opening 12'; a box 14, in which fuses, on and off switches as well as the known reversing device are provided; a gear box 16; a blade box 17; and an outlet duct 18 including an outlet opening 18'.

The gear box 16 (FIG. 2) has an upper wall 19 and a lower wall 21 which serve as the bearing supports for a perpendicularly disposed worm gear shaft 22. The worm gear shaft 22 has at its upper end an internal multi-edge opening or socket 23 into which the shaft of electric motor 13 fits. In the center region of the gear shaft 22 a worm 24 is provided which is seated secured against rotation in any conventional manner. A bearing 26 in the upper wall 19 and a bearing 27 in the lower wall 21 mount the worm shaft 22 to the bearing supports. Bearing 27 includes a double tapered roller bearing and can support an axial thrust load whose direction depends on the rotational direction of motor 13.

A worm tooth gear 28 meshes with worm 24. The worm gear 28 is mounted on a shaft 31 and secured against rotation thereon in any conventional manner. As can be seen from FIGS. 3 and 3a, shaft 31 also supports a smaller toothed wheel 32 to the right of gear 28. The right-hand end of shaft 31 is mounted to be freely suspended and rotatable in a bearing 33. The bearing 33 is screwed to the left-hand end of the cylindrical portion 34 of a hexagonal shaft 36. Bearing 33 and shaft 31 can thus rotate independently of one another, but are coaxial.

A larger toothed wheel 37 meshes with gear 32. The toothed wheel 37, (FIG. 4), is securely fastened as, for example by welding, to a hub 46. The hub 46 is wedged on the left-hand cylindrical portion 38 of a second hexagonal shaft 39. The cylindrical portion 38 includes a plurality of spline-type keys 38" each of which engages a key way 46' formed in the hub 46. The keys 38" are preferably press-fitted into the key ways 46' resulting in the wedging action. For purposes of clarity, FIG. 4 does not show the worm 24 or the worm shaft 22. The cylindrical portion 38 is stepped toward the left and terminates in a reduced diameter extension 38' which is supported in a bearing 41 of sidewall 42 of the gear box 16. At its other end, the cylindrical portion 38 passes through the right sidewall 44 of the gear box 16 and is there supported in a bearing 43. The hub 46 includes a smaller gear 47 which is integrally formed thereon. The gear 47 thus rotates at the same speed as gear 37. The gear 47 meshes with a larger gear 48 which, however, has a somewhat smaller diameter than gear 37. The gear 48 is wedged on the cylindrical portion 34, (FIG. 3), in a manner similar to that of hub 46 on cylindrical portion 38. It is thus possible to substantially reduce the number of revolutions of motor 13 and to drive the two hexagonal shafts 36 and 39 in opposite directions and at a different speed. Also, it is possible to have a ratio of shaft revolutions of approximately 40:70, for example. Of course, it should be understood that other ratios may be achieved as desired.

The gear box 16 can, for example, have a width of 19 cm, an inner height of 22.5 cm and an inner length of 59.5 cm. The gear box 16 is designed to be oil tight so that the gearing can be splash lubricated from the sump level 49. This gear box construction has been found to successfully withstand the high axial and radial forces which develop during the comminuting operation.

The blade box 17 has a stable frame structure which is open at the top to receive the trash from the hopper 12, and opened at the bottom to discharge the comminuted trash to the outlet duct 18. The frame structure includes the sidewall 44 which forms a party wall with the gear box 16. The three remaining walls 51a, 51b and a third, not shown, are generally U-shaped or channel beams which are preferably welded together. FIG. 3 shows in cross-section the channel 51b which is exemplary. The channel 51b includes, typically, a web portion 52 and flanges 52a and 52b. The upper flanges of all three walls are joined in a conventional manner such as through the use of bolt joints with a corresponding three-sided flange portion (not shown) of the hopper 12. The U-shaped beam 51b is provided in its web portion 52 with two bearing supports 52c and 52d (the latter shown in FIG. 15) for the end pins 53 of the two hexagonal shafts 36 and 39 and their associated bearings 53a and 53 b (the latter shown in FIG. 15). Each hexagonal shaft 36 and 39 bears fourteen blades 54 which are preferably similarly configured and which are each combined into groups of two 56, 57, 58, 59, 61, 62, 63. For reasons for simplicity, FIG. 3 shows only the blade groups of the hexagonal shaft 36. These blade groups are spaced apart by spacer sleeves 64, which are all of the same dimension, but which are wider than the width of a blade group which are preferably 15 mm in width, by the degree of axial play of one of the shafts 36.

It should be noted at this time that the degree of axial play is not shown in FIG. 12 because it is of such a small magnitude in comparison to the size of the elements shown. Pressure rings 66 and 67 axially pretension the entire arrangement of the blade groups and the spacer sleeves 64 when assembled as shown in FIG. 3, so that any axial displacement on the hexagonal shaft 36 is substantially eliminated.

Referring to FIG. 12 it can be seen that an qual number of blade groups 68 on the hexagonal shaft 39 are provided. These blade groups fit into each interstice between adjacent blade groups on shaft 36 so that a gap opening 69 remains through which the comminuted material can fall downwardly and through outlet opening 18'.

In one embodiment of the present invention, the blades 54 have the shape illustrated in FIGS. 5 and 6. In this embodiment the blades 54 have a hexagonal opening or bore 54' which is adapted to fit in a conforming manner on the hexagonal shafts 36 or 39. The hexagonal shafts are intentionally hardened so that their toughness index will be enhanced. The shafts 36 and 39 are made from an unhardened chromium steel, preferably 12 percent chromium steel. In contradistinction, however, the blades 54 are hardened to a Rockwell hardness of 60-62. The blades 54 are made from a material identified by the number 2090 according to DIN (Deutsche Industrie Normen, German Industrial Standards), which is a 12 percent chromium steel.

From point 72 to point 73, i.e., over an angle of 200.degree., the peripheral surface 74 defines a circular region 74' of the blade with a radius of 140 mm. The peripheral surface 76 which follows point 73 in a clockwise direction also follows a circular path whose center 77 is offset downwardly by 29 mm and to the right by 34.5 mm with respect to center 78.

A region 76' defined by the peripheral surface 76, when viewed from the center 78, has a continuously increasing radius. A step region 79' follows the region 76' and includes a tongue 79. The tongue 79 has a planar upper surface 81 which is perpendicular to the plane of the drawing and a lower surface 82 which is also planar but is inclined downwardly at an angle of 10.degree. perpendicularly to the plane of the drawing. The surface 82 is preferably ground. From the tip 83 of the tongue 79 to the beginning of region 74' at point 72, a recess 84 is formed in the approximate shape of a sicle. This recess 84 forms the receding portion of the step region 79'. More precisely, the ground surface 82 transitions into a curved surface having a radius of 15 mm and extending through an arc of approximately 120.degree., and this curved surface blends into the surface 86, which is perpendicular to the plane of the drawing and which in turn extends to point 72 of region 74'.

The vertically measured distance between surface 86 and the tip 83 of tongue 79 is 40 mm, while the surface 81 forms an angle of 75.degree. with respect to the vertical (FIG. 5). Except for the surface 82 and a portion of the adjacent curved surface having the radius of 15 mm nothing is ground along the circumference of blade 54.

Edges 88 and 89 are rounded so that they are not very sharp. The side surfaces 91 and 92, however, are ground to be plane and parallel, the thickness of the blades being preferably 15 + 0.01 mm. The opening angle of the tongue 79 defined by the surfaces 81 and 82 is preferably 30.degree. as shown in FIG. 5. It has been found that variations of this angle up to .+-. 20 percent are acceptable.

The approximately 30.degree. angle is important particularly when comminuting metal. On the one hand, it prevents the forces produced by the entrance of the metal from increasing too rapidly, which would be the case with larger angles, such as e.g., 50.degree.; while on the other hand, the angle is sufficiently large to effectively produce a large hole in the metal sheet and also large enough so that it can be pulled out of the metal sheet during each reversing process. A tongue with too small an angle would more easily penetrate into the metal, but would have difficulty in being withdrawn from the hole during reversal.

In the other embodiment of the present invention which is illustrated in FIGS. 7 and 8, blade 110 has the shape of blade 54 shown in FIGS. 5 and 6, but blade 110 has a cylindrical bore 112 which is concentric with center 111. Blade 110 also has parallel surfaces 127 and 123', which like blade 54 and 40 mm apart. Recesses 113, 114, and 116 are provided at an angular offset with respect to each other according to the relationship 360.degree./n, where n = 2, 3, 4 etc., and is preferably 3. The inner surfaces 117 of the recesses follow a circular arc of approximately 200.degree.. The distance of the center 118 of all recesses 113, 114, 116, from center 111 is the same. In the embodiment illustrated, the center 118 is disposed on the extension of the inner surface of the bore 112.

A cylindrical shaft 119 is provided which corresponds to the hexagonal shafts 36 and 39 and which has a diameter such that it can be inserted through the bore 112, so that all blades 110 can be disposed thereon. The shaft 119 has a longitudinal groove 121 which extends over the entire length of the shaft over which the blades 110 are to be mounted. As is shown in FIG. 7, the groove 121 supplements with its inner surface the inner surface 117 of recess 113 to form a circular bore 121'. Thus, when recesses 113 and longitudinal groove 121 are congruent to form the bore 121', a cylindrical rod 122 can be placed therethrough so that shaft 119 will carry the blade in both directions of rotation of the shaft. For the next blade 110, the recess 116 supplements longitudinal groove 121; for the blade 110 after that, recess 114 supplements longitudinal groove 121, etc., so that tongues 123 of blades 110, which are designed in the same manner as tongues 79 of blades 54 and which here have an opening angle of 30.degree. .+-. the variation stated above, are offset with respect to one another by a preferred angle of 120.degree.. Preferably, the bore 121' is formed such that more than one-half of the bore is within the blade body.

Alternatively, additional longitudinal grooves 121a and 121b could also be provided at the periphery of shaft 119 parallel to the longitudinal groove 121 and offset by 120.degree. so that additional bores may be formed with recess 114 and recess 116. It must be noted here, however, that any practical number of additional grooves and resulting bores are possible, but that too many longitudinal grooves would not be desirable since they would tend to weaken the shaft 119. This would also have the drawback that the longitudinal grooves would have to be manufactured on a machine with graduated circle devices since the angular offset of 120.degree. or the like must be precise. If, however, only a single longitudinal groove 121 is provided these angular relationships need not be of concern.

During the manufacturing process, holes are first drilled to correspond to the recesses 113, 114 and 116. Then bore 112 is drilled and worked with a reamer, if required. The only tool required is thus a drill.

With respect to the rod 122, the shaft 119 and the blades 110 or 125, it has been found that a rod diameter of 15 mm .+-. 4.5 mm, a shaft diameter of 40 mm .+-. 12 mm and a blade width of 280 mm .+-. 42 mm is preferable.

The blade 125 which was fabricated according to a further embodiment of the present invention as illustrated in FIGS. 9 and 10 is carried along in a form-fitting manner by shaft 119. However, it has three tongues 123, each offset by 120.degree.. The blade 125 has, therefore, the general outline of a triangle with regions each having a surface 124 which lies on a circular arc and having the same length partly defining the sides of the triangle. From the three tips 126 which later from the tip of the nose and which are designed to be cutting edges, areas 127 recede.

The surfaces 127 and 128 define a recess 127' which is generally sickle-shaped and which is large enough so that it can hold bottle necks and the like. The back of the tongue 123 is a smooth continuation of the surface 124. Tongue 123 of blade 125 like blades 54 and 110 opens at an angle of 30.degree. .+-. the variation stated above. Tongue 123 may be undercut in the same manner as tongue 79 of blade 54 to an angle of 10.degree. to form the surface 128.

Each one of the blade groups has the individual blades 54, 110 or 125, respectively, arranged next to one another without spacings therebetween so that the tips 83 or 126 of the step regions 84 or 127' of the tongues 79 or 123 are offset by 180.degree.. This explains why in FIG. 3 the right-hand blades extend higher than the left-hand blades, while the left-hand blades protrude lower than the right-hand blades. Each blade group is offset by 60.degree. with respect to the next blade group.

Let us now consider the tips 83 or 126 of the tongues of the right-hand blades 54 or 110 of each blade group 56-63. For example, the tip of the tongue of one blade for the blade group 56 is on a radius 93, (FIG. 11), and the tip of the tongue of a corresponding blade for the blade group 57 is on a radius 94 etc. The angular deviation is preferably 60.degree.. The preferably 60.degree. deviation continues with succeeding blade groups until the tip of the tongue of a corresponding blade for the blade group 63 lies on radius 93. This then results in the schematic arrangement shown in FIG. 11.

The spacing between the hexagonal shafts 36 and 39 or of the cylindrical shafts 119 is such that with a given blade configuration, the blades always overlap and define an overlap portion 95, as shown in FIG. 12.

This has the result that the blades on one shaft can be guided laterally, i.e., parallel to the shaft axis, by the blades on the other shaft and that no common gap opening along the hexagonal shafts 36 and 39 or along the cylindrical shafts 119 appears, except the limited gap openings 69, as shown in FIG. 12.

The shafts 36, 39 or 119 preferably have a center spacing of approximately 130 mm. The distance between the parallel sides of the hexagonally configured shafts 36 and 39 is preferably 41 mm.

The peripheral surface 76 makes it possible for a blade to remain in engagement as long as possible with an adjacent blade on the other shaft. Metal cans or the like are then not only crushed but also cut apart. It is insignificant which shaft receives the axial play.

However, both shafts must not have the axial play.

Blades 125 are also arranged in blade groups and are arranged to be offset with respect to one another by 60.degree. within the blade groups in a corresponding manner to blades 54 and 110.

A motor of 7.5 HP was selected for the embodiments. The motor permits the use of sufficiently long hexagonal shafts 36 and 39 or cylindrical shafts 119 for the gears employed so that fruit crates can be thrown whole into the hopper 12 and need not be broken up first. The motor 13 is also able to produce a torque which produces, with respect to the moment arms between the recesses 84 or 127' and the geometrical longitudinal axis of the shaft, moments sufficient to effect the desired comminution, Standard motors with 4 or 10 HP cannot be used because the 4 HP motor would not be powerful enough and the 10 HP motor would be too powerful. An apparatus which would be provided with a 10 HP motor would be too cumbersome for the intended purposes. A 7.5 HP motor is fed with 15 amperes. This is a value which can be handled by normal electrical lines.

The point at which motor reversal takes place can be made time or torque dependent. With respect to time dependent reversals, one would only require a clock, which would switch the motor, for example, every five minutes into a reversal of rotation. Also, a revolution counter could also be used so that the motor could be reversed, for example, every 10 revolutions.

With respect to torque dependent reversals, one could measure by how many angular degrees the ends of shaft 31, for example, are twisted with respect to one another and the reversal could be effected when a certain torsion has been reached. Also, it has been found that with a strong load, the 7.5 HP motor requires 12 amperes of current and that from this point on the motor rotation should be reversed. Since the current through the motor is proportional to the torque, the current can also be used as a criterion under the torque dependent category. In this regard consider, for example, the circuit diagram of FIG. 13. A current coil whose armature is attracted whenever the current through the motor winding has reached a certain level, for example 12 amperes, is connected in the lead to the motor winding. The armature controls a bistable member which produces the pulses shown at its output. With these pulses the polarity reversing switch is controlled from the solid line position to the dashed line position.

Another embodiment of the invention is shown in FIGS. 14, 15, in which portions which are the same as corresponding portions in FIGS. 3 and 4, are designated by the same reference numerals. It has been found that for certain comminuting applications, such as comminuting tires, axial play in one shaft of up to approximately 0.2 mm produces advantageous results. Additional axial play is achieved over the embodiment described with reference to FIG. 3 by supporting the shaft 36' by bearing 53a' which is larger than bearing 53a in the embodiment of FIG. 3. The bearing 53a' supports end pin 53' and is in turn supported within bearing support 52c', each of which is correspondingly larger to accommodate the larger bearing 53a'. As is well known, the larger the radial ball bearing, the greater the degree of axial play of the bearing and the axial play of the shaft supported by the bearing. The bearing 53a supporting the shaft 36 in the embodiment of FIG. 3 is large enough to permit the shaft 36 to move through the distance allowed by the spacing between the blades on the other shaft 39, and the larger bearing 53a' will permit the shaft 36' to move through the greater distance of 0.2 mm allowed by the spacing between the blades on the shaft 39 in this embodiment.

In this embodiment the additional axial play is accommodated in a machine of similar size to the machine described with reference to FIG. 3 by providing a single blade 54 at the end blade position 63'. The blade groups are spaced apart by spacer sleeves 64' which are of the same axial dimension, but which are 0.2 mm wider than the width of the blade group. The difference, in the order of approximately 0.2 mm, corresponds to the limits of axial play allowed on one of the shafts 36' relative to the other shaft 39. The blade groups on one shaft 36' fit into each interstice between adjacent blade groups on shaft 39. The spacing between the hexagonal shafts 36' and 39 is such that with the given blade configuration the blades 54 always overlap and define an overlap portion. Thus, as described in connection with the embodiment of FIG. 3, the blades on the one shaft 36', having axial play, can be guided laterally, i.e., parallel to the shaft axis, by the blades on the other shaft 39 with relatively no axial play.

The degree of axial play of shaft 36' is limited, as in the embodiment of FIG. 3, by the blades on the fixed shaft 39 and the axial play on the shaft 39 is limited to substantially no axial play in relation to shaft 36' as in the embodiment of FIG. 4, by the size and arrangement of the bearings supporting the shaft 39 because the embodiment shown in FIG. 15 is exactly the same as in FIG. 4.

Shaft 39 is a solid shaft end to end. It is supported at three places by bearings 140, 141 and 53b, each of which is a different size, the end bearing 140 is bearing support 41 being substantially smaller than the other bearings 141 and 53b as well as the bearings supporting shaft 36. The inherently small axial play of the small end bearing 140 is further limited by the bearing support 41 and substantially all of the axial play is eliminated from the shaft 39 by the spaced arrangement of the bearings 140, 141 and 53b along the shaft 39, which produces forces and bending moments on the bearings 140, 141 and 53b in response to the comminuting forces on the blades 54. In particular, substantially all of the axial play on the shaft 39 is eliminated by the small bearing 140, which is remote from the blades 54 and in which the inner ring of the bearing is moved radially by the comminuting forces on the blades 54 acting about the bearing 141.

It should be understood that the axial play can be substantially eliminated by other means in addition to the means described above.

It is advantageous if the engagement force exerted by the blades 54 on one shaft 36' against the adjacent blades on the other shaft 39 is limited so as not to exceed the force appropriate for smooth cutting engagement between the adjacent blades.

It is also advantageous that with the adjacent blades in engagement along one face, the maximum gap between adjacent blades along the opposite face is not so large that the material will be stuffed and chocked down between the faces, but is limited to a gap size appropriate to break up the material without choking down the machine.

To these ends, the bearing cap 29' has a threaded axial hole 131 which receives a set screw 132 having a locking nut 133 thereon.

The end of the set screw abuts and presses against a spacer 134 which, in turn, presses against the outer ring of a bearing 136 supported in the bearing cap 29'. The bearing 136 supports the end pin 135 of gear shaft 31. The shaft 36' is supported in gear box 16 by bearing 130 which is supported by a seal ring 138. A spacer ring 137 is secured to the seal ring by screws 137 one of which is shown. The spacer ring surrounds the cylindrical portion 34 of the shaft and is spaced slightly from the gear 48.

Tightening the set screw 132 against the spacer 134 reduces the play and movement of the bearing 136 to the left as shown in FIG. 14 and limits and controls the play of the shaft 36' to the left and hence the cutting force and space between the blades in that direction.

As in the embodiment of FIG. 4, the play of the shaft 36' to the right is limited by movement of the blades 54 on the shaft 36' against the blade 54 on the shaft 39' which limits and controls the cutting force and the space between the blades in that direction. Hence, the setting of the set screw 132 in relation to the blades 54 on the fixed shaft 39 controls the degree of axial play of the shaft 36' to limit the force of engagement between the blades on one shaft 36' and the adjacent blades on the other shaft 39 to a smooth cutting force and the space between adjacent blades along their opposite faces to a space advantageous for comminuting the material, in this embodiment about 0.2 mm.

The setting of the set screw 132 can also be used to adjust the degree of axial play on the shaft 36' as may be necessary from time to time.

Claims

What is claimed is:

1. Apparatus for comminuting trash comprising:

a. a motor;

b. at least two parallel shafts driven at least indirectly by said motor;

c. a plurality of disc-shaped blades disposed on each of said shafts and secured thereto for rotation therewith, each of said blades having at least one tongue extending into the direction of rotation and at least some of the blades on each of said shafts being spaced from adjacent blades on the same shaft, with the blades on one shaft extending into the spaces between blades on the opposite shaft;

d. means for rotatably supporting one of said shafts so as to have at least a predetermined degree of axial play parallel to said shaft associated therewith;

e. means for rotatably supporting the other of said shafts so as to have substantially no axial play associated therewith relative to the one shaft, and

f. the blades on one shaft extending into said spaces on the other shaft with a clearance equal to said predetermined degree of axial play.

2. Apparatus for comminuting trash according to claim 1 in which said blades are disposed at regular intervals on each of said shafts in groups of at least two blades and arranged so that the blade groups on one shaft extend into the spaces between the blade groups of the other of said shafts and the tongues of the blades on each of said shafts being angularly offset with respect to each other.

3. Apparatus for comminuting trash according to claim 2 comprising

a. means for reversing the rotation of both of said shafts;

b. an inlet above said blades; and

c. an outlet below said blades.

4. Apparatus for comminuting trash according to claim 2 in which the inner distance between two adjacent blade groups on the shaft having relatively no axial play associated therewith is equal to the degree of axial play plus the width of the blade group on the shaft having a degree of axial play associated therewith.

5. Apparatus for comminuting trash according to claim 2, in which the tongues of said blades on each of said shafts are helically offset with respect to each other along that shaft.

6. Apparatus according to claim 2 wherein the degree of axial play is approximately 0.2 mm and wherein a spacer sleeve is provided which is wider than any group of blades by the amount of said degree of play.

7. Apparatus for comminuting trash according to claim 1 in which the inner distance between adjacent spaced blades on the same shaft is equal to the degree of play plus the width of the blades on the other shaft extending into the space between said blades.

8. Apparatus according to claim 1 comprising means on the blades on the shaft having relatively no axial play associated therewith for guiding the blades on the other shaft parallel to the axis of said other shaft.

9. Apparatus according to claim 8 in which said blade means comprises flank portions on the blades on each shaft for engaging and defining an overlap portion with the adjacent blades on the other shaft.

10. Apparatus according to claim 1 comprising means on said blades for enabling the blades on one shaft to remain in cutting engagement with the blades on the other shaft beyond said tongue.

11. Apparatus according to claim 1 comprising means for limiting the force of engagement between the blades on the shaft having axial play associated therewith and adjacent blades on the shaft having relatively no axial play associated therewith, said engagement force limiting means comprising means for limiting the axial play on the shaft having axial play associated therewith.

12. Apparatus according to claim 11 comprising bearing means for supporting said shaft having axial play associated therewith and said limiting means comprises means for adjusting the position of said bearing means.

13. Apparatus according to claim 12 in which said means for adjusting said bearing means position comprises means axially disposed with respect to said shaft having axial play associated therewith for limiting the movement of said bearing means in one direction.

14. Apparatus as defined in claim 1, wherein said shafts have a center spacing of approximately 130 mm.

15. Apparatus as defined in claim 1, wherein said shafts have a hexagonal circumferential configuration, and have a width between parallel sides of 41 mm and consist of non-hardened chromium steel, preferably 12 percent chromium steel.

16. Apparatus as defined in claim 1 wherein each blade group comprises two blades which are arranged next to one another without spacings therebetween and whose step regions are offset with respect to one another, preferably by 180.degree..

17. Apparatus as defined in claim 1 wherein even groups of blades which are each substantially 15 mm wide are provided on each shaft.

18. Apparatus according to claim 1 wherein the degree of axial play is in the order of magnitude of 0.2 mm.

19. Apparatus according to claim 1 wherein the degree of axial play is up to 0.2 mm.

20. Apparatus as defined in claim 1, wherein the numbers of shaft revolutions have a ratio of approximately 40:70.

21. Apparatus as defined in claim 3, wherein the actuation of said reversing means is torque dependent.

22. Apparatus as defined in claim 1, wherein said shafts have comminuting lengths of approximately 40 cm and the gearing includes a worm meshing with a worm gear, the worm gear mounted on a shaft which has mounted thereon and secured against rotation relative thereto a smaller toothed wheel which meshes with a larger toothed wheel of the other shaft, and a second smaller toothed wheel being disposed on the other shaft and secured against rotation relative thereto which meshes with a second larger toothed wheel of said shaft, said worm being driven by a motor which is an approximately 7.5 HP motor.