US3061863A

US3061863A - Chipper hammer

Info

Publication number: US3061863A
Application number: US87693A
Authority: US
Inventors: Vernard B Bennett
Original assignee: Individual
Current assignee: Individual
Priority date: 1961-02-07
Filing date: 1961-02-07
Publication date: 1962-11-06
Anticipated expiration: 1979-11-06

Description

Nov. 6, 1962 v. B. BENNETT 3.06L863 CHIPPER HAMMER Filed Feb. 7, 1961 VfR/VA!? a &BEN/VE rr INVENTOR 3,06l,863 Patented Nov. 6, 1962 hee 3,061,863 CHIPPER HAMMER Vernard B. Bennett, 3800 Kings Way, Sacramento 21, Calif. Filed Feb. 7, 1961, Ser. No. 87,693 4 Claims. (CI. 15--236) This invention relates to a chipper hammer. It relates more specifically to such `a device for removing white painted marker lines from highway pavements and grease or grime from the floor areas of bus sections, truck .terminals, garages or factory floors.

The chipper hammer according to the present invention was primarly developed as the working tool for the Centrifugal Concrete Cleaner described and illustrated in applicant's pending application, Serial No. 57,293, filed on September 20, 1960. It is anticipated, however, that it will also be capable of use as the working tool in other types of machines for the same purpose, and will have still other uses apart from that as a Component part of cleaning machines.

The construction of the chipper hammer according to the present invention presents a number of advantages over the chipper teeth in the Centrifugal Concrete Cleaner described and illustrated in the above referred to copending application. One of these is that the chipper teeth in the machine according to the co-pending application are made of spring steel. As so made they perform their function in a satisfactory manner but breakage occurs frequently. There are also other minor disadvantages of the chipper teeth so constructed. In the chipper hammer according to the present invention, the cutter tips are shorter and are made of steel tubing, which has been case hardened.

Also in the Centrifugal Concrete Cleaner according to the above referred to co-pcnding application, the rotatable drum must be removed from the machine and dis-assembled in order to remove the chipper teeth for replacement. In the chipper hammer according to the present invention, the cutter tips can be removed from the hammer without removing the latter from the drums.

Further, in the Centrifugal Concrete Cleaner according to the above referred to co-pending application, there are two stop rods, the dogs carrying the chipper teeth restng against one stop rod on the idle arc of travel, above the horizontal diametral plane, and `abutting the other stop rod on the working arc of travel, below the horizontal diametral plane. The chipper hammer accord- 'ing to the present invention is of L shape and the drum has only one stop rod for each hammer, -one arm of the hammer abutting the stop rod on the idle arc of travel and the other arm abutting same on the working arc of travel.

An object of the present invention is to provide a chipper hammer having a cutter tip which is readily removable from the hammer itself.

Another object of the present invention is to provide a chipper hammer having a cutter tip of such shape as to leave the highway pavement from which the painted marker has been removed, or the floor from which the grease or grime has been removed, a plane and relatively smooth surface.

A further object of the present invention is to provide a chipper hammer having a removable cutter tip which can be hardened before use and which is self-sharpening during operation.

Still other objects, advantages and improvements w'ill become iapparent from the following specification, taken in connection with the accompanying drawings in which:

FIGURE 1 is a side elevational view showing the chip per hammer according to the present invention mounted between two parallel rotatable discs, with one of the discs being partially broken away, to show the mounting of the chipper hammer.

FIG. 2 is a sectional view, taken on the section line 2-2 of FIG. 1 and looking in the direction of the arrows, showing the working face of the cutter tip.

FIG. 3 is a sectional view, taken on the section line 3 3 of FIG. 1 and looking in the direction of the arrows, showing the mounting providing for chordal movement and partial swinging movement of the chipper hammer; and

FIG. 4 is a sectional view, taken on the section line 4-4 of FIG. 1 and looking in the direction of the arrows, showing the mounting of the cutter tip on the chipper hammer.

Referring now to the drawings in detail and to FIG. 1 in particular, there are here shown at 10 and 12 two parallel discs, which are part of the rotatable drum of a centrifugal concrete cleaning machine. These discs are mounted on a shaft 11 for rotaton therewith as the machine moves over the surface being cleaned. The chipper hammer is designated generally at 15 and is mounted between the

discs

10 and 12 for limited swinging movement and also for limited translatory movement radially of the discs. It will be understood that there are a plurality of the chipper hammers 15 (prefer ably at least six (6)) equally spaced arcuately of the

discs

10 and 12, but only one is here illustrated and described. In the construction of the rotatable drum according to my co-pending application, Serial No. 57,293, six of the chipper hammers are employed, between each pair of discs. As also described in the co-pending application, the rotatable drum will be comprised lengthwise by any number, up to twent'yfour (24), of the

parallel discs

10 and 12 with the chipper hammers 15 mounted therebetween for the described swinging and translatory movement.

Each chipper hammer has two arms lSa and lSb, at approximately right angles. In the position shown in FIG. 1, the arm isa abuts a stop rod 13, which is secured in aligned holes in the

discs

10 and 12. On a line approximately bisecting the angle between 15a and 15b, the chipper hammer is formed with an elongated slot 16 having semi-circular ends. In this slot there is received a rod 14, which also is secured in aligned holes in the

discs

10 and 12.

The outer end of the arm 15b is of greater thickness at 15c than the main body portion and the cutter tip 18 is mounted in this enlarged end. This tip is formed from a piece of steel tubing having a solid end portion 18b. The tubing is placed in a semi-cylindn'cal recess in a female swaging die and struck by a longitudinally aligned complementary swaging die of lesser diameter and shorter length. In its final form the tubing to `the right of the vertical diametral plane, as Viewed in FIG. 4, is positioned inwardly of and in concentric relationship with respect to the wall to the left of the vertical diametral plane. Since the male swaging die is shorter than the complementary female swaging die, the cutter tip is left with a base 1811 thicker than its working end. When the preceding step is carried out, the solid end portion 1817 is then screw threaded. The inner cylindrical threaded section 18b is received in a screw-threaded hole 17 formed in the arm 1517 of the chipper hammer transversely of the latter and is held in place by an "Allen set screw 19, which is received in a suitable screw threaded hole positioned along the longitudinal center line of the arm 15b and ntersecting the hole 17.

In operation the drum, which is comprised by an aligned series of the

parallel discs

10 and 12, rotates with the shaft 11 in the clockwise direction, as shown by the arrow in FIG. 1. For removing the painted traic lane marker lines from highway pavements, the rotatable drum will preferably have eight (8) of the sets of chipper hammers between

parallel discs

10 and 12 ranged axially of the shaft 11. This arrangement is suicient to remove a traffic lane marker line five inches wide from the highway pavement. This width can, of course, be increased or decreased at the discretion of the manufacturer of the Centrfugal Concrete Cleaner.

The drum rotates with the shaft 11 in the clockwise direction, as shown by the arrow in FIG. 1. As the discs and 12 approach the position where the rod 14 is horizontally aligned with the shaft -11, as viewed in FIG. 1, :the chipper hammer 15 is thrown outwardly and the arm 15a abuts the stop rod 13. When the cutter tip strikes the surface from which paint, grease or grimc is being removed, the chipper hammer 15 moves slghtly upwardly, the slot 16 in the latter sliding along the pivot rod 14.

The shape of the cutter tip 18, as shown in FIGS. 2 and 4, that is the double semi-circular, concentric cutting edges is a very important feature of the present invention. If the cutter tip would be left in its original round or perfect circular shape, it would remove large circular or flat ring-shaped portions of material from the surface being cleaned, leaving the surface rough and irregular. By making the cutter tip 18 in the shape shown, it removes a smaller portion of material and 'leaves the surface more regular and smooth.

Upon rebound of the cutter tip 18 from contact with the surface being cleaned, the chipper hammer 15 swings in the counter-clockwise direction, the arms 15a moving away from the stop rod 13 and the enlarged head portion 150 striking this stop rod. After the cutter tip leaves the 'surface being cleaned, the force of rebound -carries the enlarged head 15c 'away from the stop rod 13, and the arm lsa then returns into abutting position with respect to -the stop rod 13.

- As stated above the cutter tips 18 are case hardened and their life expectancy far exceeds that of the chipper rods in the Centn'fugal Concrete Cleaner of the co-pending application. Also, the cutter tips 18 are self sharpening when used to remove painted markings, grease or gri-me, from concrete surfaces, due to the abrasive action of such surfaces on the same.

Having now fully described my invention, what I claim `as new and useful and desire to secure by Letters Patent of the United States is:

l. A rotatable drum for use in wheeled surface cleaning machines movable over a surface being cleaned comprising at least two arallel plates, a pivot rod positioned between said plates adjacent the peripheries of the latter, -a stop rod posi-tioned between said plates radially inwardly of the pivot rod and forwardly of same in the direction of rotation of the drum, an L-shaped chipper hammer pivoted at its vertex on said pivot rod and having its arms adapted to selectively abut the stop rod, and `a removable cutter tip Secured in one of said arms.

2. A rotatable drum for -use in wheeled surface cleaning machines movable over a surface being cleaned, comprsing at least two parallel plates, a pivot rod positioned between said plates iadjacent the peripheries of the latter, a stop rod postioned between said plates radially inwardly of the pivot rod and forwardly of same in the direction of rotation of the drum, an L- shaped chipper hammer having portions defining an elongated slot at its vertex slidably receiving the pivot rod and having its arms adapted to selectively about the stop rod, and a removable cutter tip mounted in one of said arms.

3. A chipper hammer of L-shaped configuration having portions defining an elongated slot position approximately along the line bsecting the angle between the arms, portions of one arm of said L-shaped hammer defining a longitudinal bore theren, and a cutter tip removably mounted in said bore.

4. A chipper hammer of L-shaped configuration having an elongated slot postioned approximately along the line bisecting the angle between the arms, one of said arms having a transversely postioned screw threaded bore therein adjacent its outer end and a longitudinally postioned screw threaded hole in the outer end intersecting said transversely postioned screw threaded bore, a cutter tip having its outer free end comprised by integrally joined spaced apart concentric semi-circular wall portions. and its inner end screw threaded and received in said transversely postioned screw .threaded bore and a set screw in said longitudinally postioned hole securing said cutter :tip in place.

References Cited in the file of this patent UNITED STATES PATENTS 1,649,147 Blyth ..-V Nov. 15, 1927 2,279,922 Kraner Apr.. 14, 1942 2,911,737 Arx Nov. 10, 1959 FOREIGN PATENTS' 5 54,790 Germany July 14, 19 32