|Publication number||US3798739 A|
|Publication date||Mar 26, 1974|
|Filing date||May 19, 1972|
|Priority date||May 19, 1972|
|Publication number||US 3798739 A, US 3798739A, US-A-3798739, US3798739 A, US3798739A|
|Original Assignee||Unique Machine Tool Co Inc|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (7), Referenced by (5), Classifications (4)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent 11 1 Fritz 1 Mar. 26, 1974 ROTATING HAMMER 1,476,209 12/1923 Moen et al 72/216 2,905,033 9/1959 Gl'Ob 72/216  Inventor: Alton L. Fritz, Peoria, Arlz. 3l92756 7/1965 Cartwright H 72/216  Assignee: Unique Machine Tool Co., Inc., 3-487'669 W970 Kemp 1 13/57 Glendale Ariz. 3,488,828 l/l970 Gallagher 29/235  Filed: May 1972 Primary Examiner-Lowell A. Larson  Appl. No.: 254,860
Attorney, Agent, or FirmCharles E. Cates  ABSTRACT The invention teaches a novel rotating hammer having an eccentric perimeter which may be a plurality of radially disposed striking points which, in a preferred 8 Claims, 4 Drawing Figures ROTATING HAMMER BACKGROUND OF THE INVENTION This invention pertains to rotary hammers in general, and more specifically to rotary hammers used for applying T-mold plastic nosing and the like, wherein the operator of a machine urges a work piece against and past the hammer head which is in stationary position.
The hammer operates on the various surfaces of the work piece as they are moved by the hammer.
Rotary driven hammers are known in the prior art. The best prior art known to the inventor is a rotary driven hammer which has a round head mounted on a shaft connected by a power take-off assembly to a motor. The shaft has a cam which, in cooperation with a cam follower disposed within the circular hammer head, causes the entire hammer head to oscillate rapidly in response to the action of the cam. These prior art devices are exceedingly useful but they have a number of unfortunate problems. Among other disadvantages, they are extremely noisy, exceeding, it is thought, the proposed federal regulation for noise control in factories having government contracts and/or engaged in interstate commerce. Under those proposed regulations, noise in excess of safe level for persons working with machinery would be prohibited Another disadvantage of the prior art devices is a limited useful life approximating I days of continuous use, resulting in inconvenient and costly down time and repairs.
Another disadvantage of the prior art devices is the complexity of the manufacturing process required to produce the devices. Such devices require special drives, special bearings, and special air mist lubricating systems.
Another prior art problem is that in operation the prior art devices rotate at approximately 1,800 revolutions per minute producing a noisy jackhammer-like effect which is mentally and physically fatiguing to the operator. Furthermore, the operation of the prior art devices must be powered with a three-quarter horse power motor and the devices have an excessive kinetic energy buildup (probably due to the operation of the cam arrangement) which contributes to the undesirably short useful life. Also, ball bearings are employed in the head, and must be periodically replaced.
In light of the profound limitations of the best prior art devices, there is an urgent need for a device that can reduce the noise generated by the operation of the device to a level safe for human operators, a device simpler of construction, more durable, with a longer useful life, and which operates at a lower power requirement.
SUMMARY OF THE INVENTION The device of the present invention meets the objects recited above and has the advantages of acceptably quiet operation, longer useful life, less cost of repair, simplicity of construction, greater ruggedness, while at the same time requiring less power to operate.
The rotating hammer of this invention is a body which has an axis of rotation and an eccentric perimeter which strikes an object urged against the perimeter with repeated rhythmical blows. Entirely eliminated is the need for a cam and cam follower arrangement. A plurality of striking points may be disposed radially of the axis and are preferably equidistant from the axis and from each other. The size of the head and the number of striking points are not critical, and may be varied to suit individual preferences. The striking means maybe resiliently deformable to protect the work piece. The speed of rotation of the hammer is adjusted to operate smoothly for the particular size of the head and number of striking points employed. (At least one striking point must exist and a plurality is definitely preferred.) This can be done without undue experimentation, and a variable speed motor may be used to adjust the speed of rotation. The hammer is for use on a machine conventionally powered by a motor with suitable means for taking the power off the motor and delivering the same to the hammer.
A clearer understanding of the invention can be gained from the following detailed description of the preferred embodiments thereof, in conjunction with the drawings in which:
FIG, 1 is a plan view of the device.
FIG. 2 is an elevation view of the device of FIG. 1, in cross-section, taken along the line 22.
FIG. 3 is an enlarged view of a portion of the device as shown in FIG. 2 to illustrate the details of the roller.
FIG. 4 is a plan view of the device, mounted on the table of a rotary hammer machine for a typical T-mold plastic nosing operation.
DESCRIPTION OF A PREFERRED EMBODIMENT The rotary hammer is peculiarly useful in the application of T-mold plastic nosing to pre-slotted cabinet work such as table tops, counter tops, and door fronts. In'this special application a work piece is first prepared by forming a slot in an area to be finished with the plastic molding. The T-mold is a strip of plastic having the shape of a T in cross section. The stem of the T is serrated and when pushed into the slot, grips the sides of the slot with the serrated edges of the stem. The cross of the T presents a finished strip of plastic to view. Because of its peculiar utility for the purposeof applying T-mold nosing, the preferred embodiment of the device will be described with reference, where convenient, to its use for this purpose.
Referring now to FIG. 1 which depicts a presently preferred embodiment of the invention, the hammer'Z has a body 4 fashioned from a cylinder ofsteel of the desired dimensions. It is provided with an axial aperture 6 and counter bore 8 for the reception of a taper lock bushing (not a part of the invention). The perimeter 12 of the body 4 is milled to form an annular groove 14 in which are disposed a plurality of rollers 18. The size of the body 4 of the rotating hammer 2, the size and numbers of the rollers 18, and the diameters thereof are not criticial. It will be appreciated that the relationship of these parameters to each other and to the revolutions per minute at which the rotating hammer 2 is rotated will have a bearing on the operating efficiency of the device.
In a presently preferred embodiment, l5 rollers 18 of 1 inch diameter are equidistantly disposed around the perimeter 12 of the body 4, which is approximately 7, inches in diameter. This device is rotated at 230 revolutions per minute.
The rollers 18 are carried by shoulder pins 20. Apertures 22 and tapped holes 24 are provided in the flanges 26, 28 for the reception and retention of the pins 20. Needle bearings 34 are provided to reduce friction between the shanks 32 of the shoulder pins and the rollers 18. Roller thrust bearings 36 are disposed between the ends 38, 40 of the rollers 18 and the flanges 26, 28 respectively to maintain spacing and reduce friction.
The preferred embodiment of the invention as above described is shown in FIGS. 1, 2 and 3. FIG. 4 sets the environment in which the invention is used as an aid to understanding the function of the invention.
The rotating hammer 2 is connected to a power take off shaft by means of a taper lock bushing 50. The hammer 2 is disposed within a well 52 in the surface 54 of the table 56. Also disposed on the surface 54 of the table 56 is a T-mold feeding and cutting device 58 which guides a strip of plastic T-mold 60 to work piece 62 which has been previously notched for the reception of the stem 64 of the T-mold 60.
A human operator (not shown) maintains pressure on the work piece 62 to urge it against the rollers 18 of the rotating hammer 2. As the work piece 62 is moved relative the rotating hammer 2, the strip of plastic T- mold 60 is drawn with it. The action of the rollers against the strip of T-mold 60 forces the stem 64 into the channel 70 in the edge 66 of the work piece 62.
While only one embodiment of this invention has been described in detail, various changes and modifications can be made which fall within the spirit of this invention and the scope of the appended claims.
1. A device for applying a T-mold nosing and the like to a work piece, comprising:
a. A table having a surface;
b. A rotating hammer operatively disposed at the surface of said table and having an axis of rotation and a body having a plurality of radially spaced striking- 2. The device of claim 1 wherein said hammer is disposed within a well in the surface of said table.
3. A device for applying T-mold nosing and the like to a work piece, comprising in combination: a work piece having a suitable channel for receiving the stem of a T-mold nosing and a rotary hammer having a body with radially spaced striking means; said device adapted to be operated by urging said work piece against the perimeter of said hammer to apply the T- mold nosing to the channel of the'work piece.
4. The device of claim 3 with the addition of a table having a surface disposed to support the work piece as it is urged against the hammer.
5. The device of claim 1 wherein the radially spaced striking points comprise cylinders rotatably disposed in the perimeter of the body of said hammer.
6. The device of claim 2 wherein the radially spaced striking points comprise cylinders rotatably disposed in the perimeter of the body of said hammer.
7. The device of claim 3 wherein the radially spaced striking points comprise cylinders rotatably disposed in the perimeter of the body of said hammer.
8. The device of claim 4 wherein the radially spaced striking points comprise cylinders rotatably disposed in the perimeter of the body of said hammer.
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