WO1992018708A1

WO1992018708A1 - Concrete deck pulverizer

Info

Publication number: WO1992018708A1
Application number: PCT/US1991/006711
Authority: WO
Inventors: Kenneth R. Labounty
Original assignee: Labounty Manufacturing, Inc.
Priority date: 1991-04-10
Filing date: 1991-09-17
Publication date: 1992-10-29
Also published as: MX9102275A; ITTO910727A0; FR2675185A1; CN1065605A; BE1004775A6; ITTO910727A1; DE4201622A1; AU1236492A

Abstract

A heavy duty mobile concrete deck pulverizer (70) for attachment to the boom structure and hydraulic system of a mobile power implement has an elongate frame (72) with opposing ends. An attachment mounting assembly (49) is fixed onto the one end of the frame for mounting the frame to the boom structure as to orient the pulverizer toward or away from the implement. A pair of jaws (88, 120) with confronting concrete piercing teeth (100-106, 136, 146) are pivotally connected with respect to each other as to be opened and closed relative to each other. The jaws (88, 120) are mounted to the other end of the frame (70) in a manner offset from the elongation of the frame as to permit orientation of one of the jaws underneath the workpiece to be pulverized over a wide range of the boom structure movement. A hydraulic cylinder (150) is mounted on the frame and connected to one of the jaws (120) as to open and close the jaws.

Description

CONCRETE DECK PULVERIZER

BACKGROUND OF THE INVENTION

This invention relates to a heavy duty mobile demolition tool for attachment to the boom structure and hydraulic system of a mobile power implement.

More particularly, the demolition tool is a concrete deck pulverizer which is attachable to an implement such as an excavator or bac hoe. The concrete deck pulverizer has a frame which supports concrete crushing or pulverizing jaws in an offset manner with respect to the frame to make the tool operable on a horizontal workpiece over a wide range of boom structure movement.

In rebuilding large structures or reclaiming developed land, demolition often plays a large part. That is, to make way for improvements, buildings, bridges, roadways, airports, refineries and other obsolete facilities are often demolished and cleared. Problems arise in that government regulations and practicable considerations relating to hazardous materials and landfills do not permit the ready disposal of large chunks of demolished structures. Ideally, the structures are to be greatly reduced in size which will accommodate reclamation of certain metals and reuse of crushed frangible materials, such as concrete, as fill or as an aggregate base for roadways and the like.

The workpieces to be reduced that are associated with buildings, bridges, roadways, refineries, etc. vary greatly in composition and shape. Concrete is often found that may be reinforced and shaped into decks, floors, slabs, sidewalks, roadways, walls and the like. Asphalt may also be used. Certain of these work pieces may be at ground level. Others may be at raised levels which make the workpieces difficult to reach and quite dangerous to place men in and around to demolish. The workpieces may also be commonly associated with noncrushable structural metal materials such as beams channels, rebar, sheets, plates, pipes, rods, cables, pieces and scrap.

Consequently, attachments to mobile power implements, such as excavators and backhoes, have been developed to assist in the demolition of structures, collecting of demolished debris and scrap, and processing of the reduced materials for reuse or reclamation. U.S. Patent No. 4,519,135 issued on Hay 28, 1985 to LaBounty is for a metal demolition shear. The shear is unique for demolition, reduction and processing of crushable and some noncrushable structural materials. Such materials may include beams, channels, plates, pipes, rods and other metal scrap. The shear essentially reduces the materials by shearing or tearing. U.S. Patent No. 4,838,493 issued on June 13, 1989 to LaBounty is for a concrete crusher for use with crushable or frangible materials or workpieces. The crusher reduces, breaks or fractures the crushable materials such as reinforced and nonreinforced concrete. U.S. Patent No. 4,017,114 issued on April 12, 1977 to LaBounty shows a multi-directional grapple which is typically used for collecting the reduced materials and scrap. The collected materials and scrap are then placed into the back of a truck or rail car for transportation to a remote location for reuse, disposal or reclamation. The grapple patent also reveals a rotational assembly which permits a multitude of angles for orienting the grapple.

There are problems associated with these attachments and the excavators upon which they are attached and used. The attachments have a limited range of use with respect to the boom structure and the excavator. That is, the demolition tools, and more particularly their jaws, are mounted as straight rigid extensions onto the dipper stick or arm of the boom structure. Sometimes the attachments are mounted directly onto the actual boom as an extension of the boom. Some attachments have their jaws mounted on to a frame which is an in line extension of the dipper stick or boom. With these arrangements, the orientation of the attachment on the boom structure for operation often requires movement of the excavator to permit the attachment to reach and orientate the workpiece into the jaws of the tool for reduction or demolition.

There is a need for a heavy duty mobile concrete deck pulverizer that has a frame that will support a unique concrete deck pulverizer jaw structure in an offset manner with respect to the frame. The pulverizer will be fully operational to work on substantially horizontal workpieces over the full range of the boom structure movement without repeated moving of the excavator. This range of operation would also include the pulverizing of concrete decks, floors, slabs, sidewalks, roadways and the like on various horizontal levels from close to and far away from the tracks of the excavator. SUMMARY OF THE INVENTION

A heavy duty mobile concrete deck pulverizer for attachment to the boom structure and hydraulic system of a mobile power implement has an elongate frame with opposing ends. An attachment mounting assembly is fixed onto the one end of the frame for mounting the frame to the boom structure as to orient the pulverizer toward or away from the implement. A pair of jaws with confronting concrete piercing teeth are pivotally connected with respect to each other as to be opened and closed relative to each other. The jaws are mounted to the other end of the frame in a manner offset from the elongation of the frame as to permit orientation of one of the jaws underneath the workpiece to be pulverized over a wide range of the boom structure movement. A hydraulic cylinder is mounted on the frame and connected to one of the jaws as to open and close the jaws.

A principle object and advantage of the present concrete deck pulverizer is its unique elongate frame which supports an offset jaw structure to permit the pulverizer to operate over the full range of boom structure movement as to pulverize concrete adjacent the cab to the full reach of the boom structure without necessarily moving the excavator to position the pulverizing jaws.

Another advantage and object of the present concrete deck pulverizer is that it has a unique mounting assembly which permits easy and quick mounting as to orient the concrete deck pulverizer either toward or away from the excavator depending upon whether the operator wishes to demolish the workpiece by drawing the boom structure toward or away from the cab. Another principle object and advantage of the present invention is that the concrete deck pulverizer has a unique mounting structure which is readily adaptable to be mounted either on the dipper stick or the boom of the excavator as well as to mount the pulverizer either toward or away from the cab.

Yet another object and advantage of the present invention is that the elongate frame is of a box construction adding light weight strength, durability and protection to the operating, and moving parts of the concrete deck pulverizer.

Still another object and advantage of the present invention is that the pulverizer permits demolition of difficult and hard to reach concrete deck, floors, slabs, sidewalks, bridges and roadways that may be extremely close to the excavator, far away from the excavator or elevated up and away from the excavator.

Yet another principal and advantage of the concrete deck pulverizer is its unique offset, wedge-shaped lower jaw which once underneath the concrete workpiece, lifts the workpiece into the jaws for pulverization as the concrete deck pulverizer is moved toward or away from the excavator depending on whether the operator wishes to demolish the concrete work piece by drawing the pulverizer toward or away from the cab. The sloping wedge shape of the lower jaw assists in the cleaning the pulverizer as pulverized materials fall out of the jaws once crushed.

Still another object and advantage of the present invention is the concrete deck pulverizer jaws includes a small shear which will shear, cut or break reinforcing bar which may be encountered in the concrete to be pulverized. The shear will permit the pulverizer to continue to pulverize reinforce concrete as the operator draws the boom structure toward or away from the cab.

Finally, yet another principal object and advantage of the present invention is that the confronting concrete piercing teeth are directed somewhat inwardly towards the pivotal connection of the jaws as to aid in catching, holding and retaining the concrete workpiece upwardly within the jaws before the jaws are closed and the pulverization takes places.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of the concrete deck pulverizer with a rotator-type attachment mounting assembly and the offset jaws being open;

FIG. 2 is a side elevational view of the concrete pulverizer attached to the boom structure of an excavator, the frame and upper jaw are partially broken away.

FIG. 3 is a cross-sectional view taken along lines 3-3 of FIG. 2 showing a top plan view of the lower jaw;

FIG. 4 is a cross-sectional view taken along lines 4-4 of FIG. 2 showing a bottom plan view of the upper swingable jaw;

FIG. 5 is a side elevational view similar to FIG. 2 with the jaws in their closed position; FIG. 6 is a cross-sectional view of the concrete deck pulverizer jaws taken along lines 6-6 of FIG. 5;

FIG. 7 is a cross-sectional view of the jaws of the concrete deck pulverizer taken along lines 7-7 of FIG. 5.

FIG. 8 is an operational view of the concrete deck pulverizer attached to the boom structure of an excavator about to begin work on concrete immediately adjacent the excavator; and

FIG. 9 is a view similar to FIG. 8 showing the concrete deck pulverizer at the end of the reach of the boom structure after having pulverized a substantially lengthy workpiece of concrete into rubble.

DETAILED SPECIFICATION

Although the concrete deck pulverizer of the present invention is shown in FIGS. 1-8, some background about mobile power implements is firstly appropriate. Mobile power implements more specifically may be described as excavators 10, backhoes or the like as shown in FIGS. 8 and 9.

Excavator 10 is mounted on a pair of continuous tracks 12 which permit the excavator 10 to crawl along the ground. Wheels may also sometimes be used. Rotatably mounted above the tracks is cab 14 or swinghouse 14. The operator sits within the cab to operate the excavator 10. The articulated boom structure generally includes the boom 16 pivotally mounted at 18 to both sides of the cab 14 upon which the dipper stick or arm 24 is pivotally connected for supporting the concrete deck pulverizer at the stick end 28.

More specifically, boom 16 is mounted at pivot 18 to cab 14. A hydraulic actuator or hydraulic cylinder 20, which includes a piston and ram, is pivotally connected to the boom 16 and cab 14 to permit raising and lowering of the boom 16. The end of the boom 16 has a pivot point 22 upon which the dipper stick 24 is pivotally mounted. A hydraulic cylinder 26 pivotally connects the top of the boom 16 and the end of the dipper stick 24 as to move the dipper stick 24 upwardly and away from the cab as well as downwardly and toward the cab with respect to the boom 16. The stick end 28 of the dipper stick or arm 24 appropriately has a pivot pin aperture therethrough for supporting a transverse pivot pin 32 (FIGS. 2 and 5) for mounting an attachment to the end 28 of the dipper stick 24 of the excavator 10.

Attachment swinging linkage 34 may be used in connecting an attachment to the stick end 28 of the dipper stick 24. Linkage 34 includes a pair of spacer links 36 which are pivotally connected to the pivot mount 38 at the stick end 28 of the dipper stick 24. Away from pivot mount is the linkage pivot point 40 which will permit the attachment of cylinder 41 to the swinging linkage 34 perhaps by a cylinder ram having a pin 43 at its end which may be interchangeable or the same as pin 40. Also connected to pivot point 40 are a pair of attachment links 44 which are directed towards and connected to the attachment at their respective ends. Attachment links 44 are suitably and pivotally held thereat by pin 50 thereby locking the swinging linkage 34 to the attachment. Referring to FIGS. 1-9, the attachment mounting assembly 49 of the present invention is generally illustrated. However, the attachment mounting assembly 49 generally may include parallel, like and opposing plates 52, which are mounted on a base plate or attachment frame cap, top or end 74 as by welding or weldments. However, the attachment mounting assembly 49 may include the construction of a rotator assembly 58 which is known in the art and further disclosed in the referenced '114 patent issued to LaBounty.

The details of the concrete deck pulverizer 70 may now be appreciated and studied by referring to FIGS. 1-7. The pulverizer 70 may be constructed of strong metal and consists of an elongate frame 72 which is preferably of a box-like construction in that it is substantially closed. Frame 72 includes closed top, cap or end 74, closed rear wall 76, closed side walls 78 and partially opened front wall 80. Front wall 80 has an elongate opening 82 therethrough to permit access into the frame interior 84.

The bottom end 86 is closed by the rigid fastening of the lower jaw structure 88 to the frame 72. That is, the lower wedge shaped jaw structure 88 is fixed to the bottom end 86 of frame 72 suitably by welding. The lower jaw 88 is substantially perpendicular or offset with respect to the elongation or direction of the box frame 72. For many applications, the lower jaw 88 is suitably directed approximately 90* from the elongation of the frame 12 or substantially perpendicular with respect to the frame. See the horizontal line H above the lower jaw 88 compared to the vertical frame 72 in FIG. 2. In some applications, substantially perpendicular may range wherein the lower jaw 88 in relation to the frame 72 ranges from 45" to 135", 65" to 125°, or 75" to 110".

The lower wedge jaw 88 is preferably box shaped for strenth and light weight. Jaw 88 is comprised of side plates 90 which are joined to the closed side walls 78 as by welding. A rear support plate 92 also may be welded to the closed side walls 78 on the frame interior 84 and will add strength to the structure. A deck or top plate 94 is suitably welded to the top edges of side plates 90 as by welding. Also, bottom plate 96 may be welded to side plates 90 and to portions of the rear and side walls 75 and 78 of frame 72. There may also be a second bottom wear plate 97 attached to bottom plate 96. At the tip of lower jaw 88 suitably is fastened a hardened tip plate 98 which resists wear.

The deck or top plate 94 of lower jaw 88 supports outer teeth, tips, lugs or grid plates 100, 102 as well as inner teeth tips, lugs or grid plates 104, 106. Plates 100, 102, 104, 106 support points, teeth, tips or lugs 108 which suitably are in a row or in line and somewhat directed toward the frame 72. It is conceivable that the plates 100, 103, 104, 106 may be readily replaceable as by bolts or welding. Between the plates 100, 102, 104, 106 are spaces 108.5 discussed later herein. Teeth or grid plates 106 supports a rearwardly located lower shear knife or blade 112 which is part of the small shear 110 which suitably may be a part of the concrete deck pulverizer 70. Upper moveable jaw 120 pivots with respect to the lower jaw 88 and is also appropriately of a box designed for strength and light weight. Upper jaw 120 is comprised of side plates 122 and contoured top plate 124 which appropriately are welded together. On top of top plate 124 is located cylinder brackets 126 which suitably may support apertures 128 therethrough. Through side walls 78 is main pivot aperture 130 through which the main pivot 132 may be located which will permit pivoting of the upper jaw 120.

Upper jaw 120 has a deck or bottom plate 134 which suitably supports outer teeth, tips, lugs or grid plates 136 and 138 which have teeth, lugs, tips or points 140. Between plates 136 and 138 is located an inner teeth plate 142 which also has teeth, tips or lugs 144 which are somewhat directed towards the frame 72 along with teeth 140.

Spaces 144.5 and 108.5 are located between teeth 108 and 144 as to disalign teeth 140 and 144 of the upper jaw 120 with respect to the teeth 108 to permit rubble to fall therein and to prevent jamming. The inner teeth plate 142 suitably has an outermost long, enlarged or elongate tooth or tip 146. Suitably an upper shear blade 148 of shear 110 may have a hardened insert and is located rearwardly along the inner teeth plate 142.

A hydraulic actuator such as a hydraulic cylinder 150 has a mounting bracket 152 for securing to the bracket 126 of the upper moveable jaw 120. Cylinder 150 is held thereat by pin 154. From bracket 126, cylinder 150 extends through the elongate opening 82 of front wall 80 where ram pin 158 is suitably attached in side walls 178 and connected to cylinder ram bracket 156. The mounting advantages and operation of the concrete pulverizer 10 may now be readily appreciated. The attachment mounting assembly 49 permits the pulverizer 70 to be readily mounted facing toward or away from the cab 14. That is, the stick end 28 of the dipper stick 24 and the swinging linkage 34 readily attaches to the mounting plates 52. A rotator assembly 58 may be incorporated into the attachment mounting assembly 49 to permit hydraulic rotation of the pulverizer 70 to orient the frame 72 and jaws 88 and 120 in any horizontal direction. Further still, the pulverizer 70 may be attached to either the dipper stick 24 or the boom 16.

The concrete deck pulverizer 70 is ideal for crushing and pulverizing horizontal concrete workpieces such as slabs, decks, side walls, and the like. As can be seen by FIGS. 8 and 9, the jaws 88 and 120 are substantially perpendicular or offset with respect to the elongation of frame 72. Also, the dipper stick 24 is pivotally connected to the attachment mounting assembly 49. By this arrangement, the jaws 88 and 120 can be properly oriented to pulverize a concrete workpiece W into rubble R throughout the full range of movement of the boom structure 16 and 24. The wedge shaped lower jaw 88 and the somewhat inwardly directed teeth 108 and 140 assist in moving the workpiece W up into the jaws and holding the workpiece W there until the jaws are closed to pulverize the workpiece. It may be appreciated that elongate tooth 46 begins to pierce the concrete or frangible material first as the outermost teeth 140 and 108 next begin to pierce the concrete as to assure that the maximum hydraulic power is not all used at once but in progression. Spaces 108.5 and 144.5 accept the pulverized rubble which falls out of the jaws 88 and 120 upon their opening due to the downward sloping of wedge shaped lower jaw 88.

Hardened tip plate 98 and second bottom wear plate 97 assure the long life of the concrete deck pulverizer 70 for continuous operation. The overall box shape of the jaws 88, 120 as well as the frame 72 add durability and strength to the concrete deck pulverizer 70. As stated, frame 72 further protects the moving parts of the pulverizer including main pivot 132 and cylinder 150.

The operation of the deck pulverizer 70 may now be appreciated. Perhaps initially with a continuous workpiece W a hole is punched therethrough as shown in FIG. 8. Thereafter the hardened tip plate 78 together with the wedge shaped lower jaw 88 may be moved along and lift the workpiece W by action of the boom structure movement. Simultaneously, the jaws 88 and 120 are opened and closed and the rubble R falls out of the pulverizer 70 upon the jaw opening. Small shear 110 may cut, sever or break any reinforcement or rebar which may be within the concrete. As the boom structure 16 and 24 is moved away toward the cab, the concrete deck pulverizer 70 is simply pivoted with respect to the boom structure to maintain the proper orientation of the pulverizer 70 with respect to a substantially horizontal workpiece W. For all practical purposes, the workpiece may also be elevated or lowered with respect to the excavator 10. The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof; therefore, the illustrated embodiment should be considered in all respects as illustrative and not restrictive, reference being made to the appended claims rather than to the foregoing description to indicate the scope of the invention.

Claims

WHAT IS CLAIMED:

1. A heavy duty mobile concrete deck pulverizer for attachment to the boom structure and hydraulic system of a mobile power implement, comprising:

(a) an elongate frame with opposing ends;

(b) an attachment mounting assembly fixed onto one end of the frame for mounting the frame to the boom structure;

(c) a pair of upper and lower jaws with confronting concrete piercing teeth, the jaws being pivotally connected with respect to each other as to be opened and closed relative to each other and being mounted to the other end of the frame offset from the elongation of the frame as to permit orientation of the lower jaw under the workpiece to be pulverized over a wide range of boom structure movement;

(d) a hydraulic cylinder mounted on the frame and connected to one of the jaws as to open and close the jaws.

2. The heavy duty mobile concrete deck pulverizer of claim 1 wherein the lower jaw is rigidly attached to the frame while the upper jaw is connected to the hydraulic system and pivotally mounted to the frame.

3. The heavy duty mobile concrete deck pulverizer of claim 1 wherein the frame is boxlike with the lower jaw rigidly attached to the frame and closing the other end.

4. The heavy duty mobile concrete deck pulverizer of claim 3 wherein the hydraulic cylinder and the upper jaw are pivotally mounted within the frame as to swing outward through a frame opening and toward the rigid jaw.

5. The heavy duty mobile concrete deck pulverizer of claim 3 wherein the one end is closed by the attachment mounting assembly.

6. The heavy duty mobile concrete deck pulverizer of claim 1 wherein the lower jaw is rigidly attached to the other end of the frame and substantially perpendicular to the frame.

7. The heavy duty mobile concrete deck pulverizer of claim 6 wherein the rigid jaw is wedge-shaped as to lift the workpiece into the jaws as the pulverizer is moved toward the workpiece.

8. The heavy duty mobile concrete deck pulverizer of claim 6 wherein the rigid jaw has a hardened tip plate.

9. The heavy duty mobile concrete deck pulverizer of claim 7 wherein the jaws are of a boxlike construction.

10. The heavy duty mobile concrete deck pulverizer of claim 1 wherein the jaws have opposing plates, each plate supporting the teeth which are staggered with respect to the teeth of the opposing plate.

11. The heavy duty mobile concrete deck pulverizer of claim 10 wherein the teeth on each plate form at least three rows.

12. The heavy duty mobile concrete deck pulverizer of claim 10 wherein the teeth are somewhat directed inwardly toward the pivotal connection of the jaws.

13. The heavy duty mobile concrete deck pulverizer of claim 1 wherein the outermost tooth of one of the jaws is elongate.

14. The heavy duty mobile concrete deck pulverizer of claim 1 where the jaws each support a small shear blade adjacent their pivotal connection.

15. A heavy duty mobile concrete deck pulverizer for attachment to the boom structure and hydraulic system of a mobile power implement, comprising:

(a) an elongate frame with opposing ends;

(b) an attachment mounting assembly fixed onto the one end of the frame for mounting the frame to the boom structure as to orient the pulverizer toward or away from the implement;

(c) upper and lower jaws with confronting but staggered concrete piecing teeth, the jaws being pivotally connected with respect to each other as to be opened and closed relative to each other, the lower jaw being wedge shaped and mounted to the other end of the frame substantially perpendicular to the frame as to orient of the lower jaw underneath the workpiece to be pulverized over a wide range of boom structure movement; and

16. The heavy duty mobile concrete deck pulverizer of claim 15 wherein the lower jaw is rigidly attached to the frame as to lift the workpiece into the jaws as the pulverizer is moved toward the workpiece.

17. The heavy duty mobile concrete deck pulverizer of claim 15 wherein the lower jaw has a hardened tip plate.

18. The heavy duty mobile concrete deck pulverizer of claim 16 wherein the jaws are of a boxlike construction.

19. The heavy duty mobile concrete deck pulverizer of claim 15 wherein the jaws have opposing plates, each plate supporting the teeth which are staggered with respect to the teeth of the opposing plate.

20. The heavy duty mobile concrete deck pulverizer of claim 19 wherein the teeth on each plate form at least three rows.

21. The heavy duty mobile concrete deck pulverizer of claim 19 wherein the teeth are somewhat directed inwardly toward the pivotal connection of the jaws.

22. The heavy duty mobile concrete deck pulverizer of claim 15 wherein the outermost tooth of one of the jaws is elongate.

23. The heavy duty mobile concrete deck pulverizer of claim 15 where the jaws each support a small shear blade adjacent their pivotal connection.

24. The heavy duty mobile concrete deck pulverizer of claim 15 wherein the lower jaw is rigidly attached to the frame while the upper jaw is connected to the hydraulic system and pivotally mounted to the frame.

25. The heavy duty mobile concrete deck pulverizer of claim 15 wherein the frame is boxlike with the lower jaw rigidly attached to the frame and closing the other end.

26. The heavy duty mobile concrete deck pulverizer of claim 25 wherein the hydraulic cylinder and the upper jaw are pivotally mounted in the frame as to swing outward through a frame opening and toward the lower jaw.

27. The heavy duty mobile concrete deck pulverizer of claim 26 wherein the one end is closed by the attachment mounting assembly.

28. The heavy duty mobile concrete deck pulverizer of claim 15 where in the attachment mounting assembly comprises a rotator assembly.

29. The heavy-duty mobile demolition tool of claim 15, wherein the attachment mounting assembly comprises a pair of opposing plates adapted to pivotally and reversibly connect to the boom structure and to opposing pairs of attachment swinging linkage.

30. The heavy-duty mobile demolition tool of claim 29, wherein each plate has three triangularly arranged apertures therethrough for reversible connection to the boom structure and linkage.

31. A heavy duty mobile concrete deck pulverizer for attachment to the boom structure and hydraulic system of a mobile power implement, comprising:

(a) an elongate box frame with opposing ends;

(c) upper and lower jaws with concrete piecing teeth pivotally connected with respect to each other as to be opened and closed relative to each other, the upper jaw being pivotally mounted within the frame and the lower jaw being wedge shaped and rigidly mounted to the other end of the frame substantially perpendicular to the frame as to orient of the lower jaw underneath the workpiece to be pulverized over a wide range of boom structure movement; and

(d) a hydraulic cylinder mounted within the frame and connected to the upper jaw as as to swing the upper jaw and the cylinder outward through a frame opening and toward the lower jaw as to open and close the jaws.

32. The heavy duty mobile concrete deck pulverizer of claim 31 wherein the rigid jaw has a hardened tip plate.

33. The heavy duty mobile concrete deck pulverizer of claim 31 wherein the jaws are a boxlike construction.

34. The heavy duty mobile concrete deck pulverizer of claim 31 wherein the jaws have opposing plates, each plate supporting the teeth which are staggered with respect to the teeth of the opposing plate.

35. The heavy duty mobile concrete deck pulverizer of claim 34 wherein the teeth on each plate form at least three rows.

36. The heavy duty mobile concrete deck pulverizer of claim 31 wherein the teeth are directed inwardly toward the pivotal connection of the jaws.

37. The heavy duty mobile concrete deck pulverizer of claim 31 wherein the outermost tooth of one of the jaws is elongate.

38. The heavy duty mobile concrete deck pulverizer of claim 31 wherein the jaws each support a small shear blade adjacent their pivotal connection.

39. The heavy duty mobile concrete deck pulverizer of claim 31 wherein substantially perpendicular is defined by an angle between the lower rigid jaw and the frame ranging from 45" to 135".

40. The heavy duty mobile concrete deck pulverizer of claim 31 wherein substantially perpendicular is defined by an angle between the lower rigid jaw and the frame ranging from 65* to 125".

41. The heavy duty mobile concrete deck pulverizer of claim 31 wherein substantially perpendicular is defined by an angle between the lower rigid jaw and the frame ranging from 75" to 110".

42. The heavy duty mobile concrete deck pulverizer of claim 31 wherein substantially perpendicular is defined by an angle between the lower rigid jaw which equals approximately 90".