US2831378A - Sound insulated drop hammer head - Google Patents

Description

April 1958 G. J. MATEY ETAL 2,831,378

SOUND INSULATED DROP HAMMER HEAD Filed Sept. 1, 1955 INWWHWS GEORGEMATE WILLIAM A.DEHL

ATTORNEY U i a e a e SOUND INSULATED DROPHAMMER HEAD George J. Matey, Rolling Hills, and William A. Dehler,

Los Angeles, Calif., assignors to North American Aviation, Inc.

Application September 1, 1955, Serial No. 531,969

7 Claims. (Cl. 78-43) This invention relates to a drop hammer head and in particular relates to an improved long-wearing sound insulated drop hammer head.

Drop hammer heads heretofore used in various metal forming operations in industrial use have been formed of cast steel and would develop cracks after being in operation only a few months. Once such cracks appeared in the cast steel head, it would be necessary to scarf out the section containing the cracks and to rebuild these regions by applying weld metal to them. This method of repair was extremely laborious and expensive and was required to be performed almost daily as the hammer heads deteriorated with continuous service. After approximately twelve to eighteen months the head would require complete replacement. A second great disadvantage of the cast steel heads, of almost equal importance, was that upon impactthey would emit a loud ringing sound that was very disturbing to. the operators.

The present invention contemplates a drop hammer head constructed of welded hot rolled steel plate, stress relieved after welding, and having a filler slab of a semielastomeric material incorporated in the hammer head for dampening of the impact energy shock waves.

It is an object of this invention to provide a drop hammer head for metal forming work that will have a longuseful life span.

It is also an object of this invention to provide a drop hammer head that is quieter in operation than conventional hammer heads now in use.

It is a further object to provide a drop hammer head that is more efiicient and less of a strain on the operators than conventional hammer heads.

It is a still further object to provide a drop hammer head that will eliminate maintenance problems to a great extent.

Still a further object is to provide a drop hammer head that will withstand fatigue failure upon repeated impact.

Other objects and advantages of the invention will be apparent from a consideration of the following description and claims.

In the accompanying drawings:

Fig. l is a perspective view of the preferred embodiment of the invention.

Fig. 2 is a fragmentary sectional view taken along the plane of the line 22 in Fig. 1.

Referring specifically to the drawings, wherein like reference characters have been used throughout the several views to designate like parts, and referring at first to Fig. l, the drop hammer head 1 has a generally rectangular face plate 2. On the top face of the plate 2 bar members 3 and bar members 4 are rigidly fixed, as by Welding, to form a recess or cavity 16. Members 3 and 4 are set back from the edges of plate 2 a sutficient distance to provide space for a large fillet weld bead attaching members 3 and 4 to plate 2. Extending vertically upward from each of the members 4 is a truncated triangular plate 5 having its longest edge welded or fixedly attached Ill .to the upper surface of member 4. Lugs 1' project laterally outward from face plate 2, one on each of the two 1 sides of plate 2 that carriesmembers 4 and plate 5, at

points midway between the ends of the face plate. .On 1 the outer end of the lug and along the centerline thereof are provided in the bronze bearing plates. Vertically and rigidly mounted along the transverse axis of the face plate 2 in line with the V-notch grooves on the opposite edges of the face plate is the center plate 6. The enlarged vertical edges 15 of the center plate 6 abut the inner surfaces of the vertical plates 5 and the members 4 and are welded to each of them. An'integral lug 11 I projects outwardly at each upper corner of the center plate 6 over the truncated top surface of the triangular plate 5 and is rigidly attached thereto. 'Each lug 11 has a V-notch groove 1% opening outwardly at the outer end I thereof and a bronze bearing plate 12 mounted on each face of the groove. This upper slide bearing is vertically aligned over the previously described lower slide bearing.

Centrally positioned near the upper edge of plate 6 is hole 14 provided for attachment of the drop hammer control rope (not shown).

A plurality of sleeves 13 are vertically and rigidly attached to the upper surface of the face plate 2 in the recess is. The upper ends of the sleeves are flush with the upper surfaces of members 3 and members 4. Each sleeve 13 has an inner cylindrical bore 20 matching and forming a continuation of the holes 21 in face plate 2.

In mounting the die punch 27 on the hammer head, die

punch attaching pins 23 are inserted through the holes in the plate 2 and through the sleeves 13 and are each secured in place by a nut 25 and washer 24.

The hammer head of this embodiment is of an all Welded hot rolled steel plate construction with the internal stresses being relieved by heat treating after welding has taken place. Furthermore all of the-welds are designed to be in compression on the drop stroke of the hammer head.

It has been found that the welded hot rolled steel prototype head of this invention lasted for nearly a year before the first sign of any cracks was observable, and then the cracks were found to exist in a faulty weld.

To dampen the sound and absorb a portion of the vibration energy of the impact, a dampening filler slab 26 of a semi-elastic type is placed'in the recess 16 flush with the top of the sleeves 13 and the members 3 and 4. In the embodiment of the invention described herein, the semi-elastomeric material consisted of a mixture composed of approximately 50% Kish 358A flexible epoxy resin and 50% granulated cork of approximately onefourth inch particle size. This mixture is poured into the recess 16 and when set up forms a slab with the sleeves 13 projecting therethrough. The sleeves 13 each have an annular groove 22 near the upper end thereof which is filled with the epoxy-cork mixture and which serves to assist in mechanically bonding the filler slab to the sleeves and preventing displacement of the slab. It will be understood that any suitable sound absorbing material could be used for the filler slab.

This semi-elastic filler slab not only reduces the noise level of the hammer operation, but it also increases the life of the hammer head by absorbing vibrational energy that would otherwise necessarily be absorbed by the material of the head itself.

It has been found that a welded head with an epoxy- Patented Apr. 22, 1958- cor'k tiller slab has sense emission level of 107 decibels upon impact as compared to 118 decibels for an old-style cast steel head. However, the major benefit in this respect is in the tonal quality of thesound emitted at impact. The'-reverber ant-ring'ing' sound of the cast-steelhead when: dropped hasbeen replaced by the dull thudding" noise of the hammer head of this invention. This sound deadening has contributed materially to the psychological and physiological improvement of the operators of the die punch machines. I

Although only o'ne embodiment of this invention has beenillustrated and-described herein, it will be apparent that various changes and" modifications may be made in the construction, composition and the arrangement of the" various parts without departing from the spirit and scope of this invention, and that only such limitations shall be placed thereupon as are specifically set forth in the' appe'nded claims.

We claim:

I. A wear-resistant sound-deadened drop-hammer head comprising a face plate havingta cavity formed on the upper surface thereof and a plurality'of apertures through said: plate, hollow cylindrical sleeves attached to the upper surface of said plate, each one of said sleeves being positioned over one of said apertures and forming a continuation thereof thereby forming an attaching means whereby a die punch may be bolted to said face plate, oppositely disposed guide means attached to several sides of said face plate for slidable contact with suitable guide rails, and a semi-elast'o meric type sound insulating material in said cavity whereby the impact sound out-put level of the hammer is reduced upon dropping of the hammer.

2. A drop-hammer head as in claim 1 wherein the soundinsulating material comprises a mixture of approximately 50% flexible epoxy resin and 50% granulated cork.

3. In combination, a drop hammer head having a face plate comprisingits lower surface, means on said head for attaching a die punch beneath the face plate of said head, a recess formed on the upper portion of said head and extending substantially over the whole area of the upper surface of said-head, and an impact energy absorbingmeans substantially filling said recess for reducing the impact sound output level as well as the impact stresses in said head caused by dropping of the hammer head and an attached die punch.

4. The combination set forth in claim 3 wherein said impact energy absorbing means comprises a semi-elasto' meric material.

5. A wear-resistant, sound-deadened drop hammer head comprising a face plate, means on said face plate for attaching a die punch therebelow, members integrally attached to the upper surface of said face plate substantially along the edges of said plate to form a recess thereon, said recess being greater in depth than the thickness of said face plate, and an impact energy absorbing meanssubstantially filling said recess for reducing the impact sound output level as well as the impact stresses in said head caused by dropping of the hammer head and attached die punch.

6. A wear-resistant sound-deadeneddrop hammer head as set forth in claim 5 wherein said impact energy absorbing means comprises a semi-elastomeric mixture of epoxy resin and cork particles. I I

7. A welded drop hammer he'ad' formed of hot'rolled, stress relieved steel plate comprising a faceplate having a plurality of apertures therethrough, a plurality of cylindri-cal sleeves concentric with said apertures and integral with the upper surface of said face plate to form an attaching means whereby a die punch may be bolted to said face plate, members integrally attached to the up er surface of said plate substantially along the edges thereof to form a cavity on the upper surface of said face plate, said recess being greater in depth than the thickness of the face plate, and semi-elastomeric sound absorbing material substantially filling said cavity for reducing the impact sound output level as well as the impact stresses: in said head caused by dropping of the hammer head and attached die punch.

References Cited-in the file of this patent UNITED STATES PATENTS 1,118,010 Huhn Nov. 24,1914 1,181,795 Patten May 2, 1916 1,695,684 Eaton Dec. 18-, 1928' 1,720,592 Fitzgerald July 9, 1929 2,198,764 Edwards Apr. 30, 1940 2,306,627 Johansson Dec. 29, 1942 2,719,443 Derbyshire Oct. 4, 1955' FOREIGN PATENTS 828,471 Germany Jan. 17, 1952'-

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