US3618678A - Impact head for impact tools - Google Patents

Abstract

An impact head particularly suited for use with hand-held pneumatically operated impact tools, characterized by a metallic core having a base portion including therein a screw-threaded, axial bore adapted for use in coupling the impact head with an impact tool, and a coaxially related distal portion including a circumscribing annular rib embedded in an impact block formed of an homogeneous mass of synthetic resin. A particular feature of the impact head resides in an annular array of openings extended through the embedded rib in a manner such that the resin fills the openings and completely surrounds spaced segments of the rib for effectively integrating the core and the block.

Description

United States Patent 2,604,914 7/1952 Kahlen 145/29 B X 2,989,101 6/1961 Carmien 145/29 A 3,323,202 6/1967 Brower et a1. 173/131 X Primary Examiner-David H. Brown Attorney-Huebner & Worrel ABSTRACT: An impact head particularly suited for use with hand-held pneumatically operated impact tools, characterized by a metallic core having a base portion including therein a screw-threaded, axial bore adapted for use in coupling the impact head with an impact tool, and a coaxially related distal portion including a circumscribing annular rib embedded in an impact block formed of an homogeneous mass of synthetic resin. A particular feature of the impact head resides in an annular array of openings extended through the embedded rib in a manner such that the resin fills the openings and completely surrounds spaced segments of the rib for effectively integrating the core and the block.

[72] inventor Arthur .1. Smith P. 0. Box 3274, Vkalia, Calif. 93277 1211 Appl. No. 47,768 [22] Filed June 19, 1970 [45] Patented Nov. 9, 1971 [54) IMPACT HEAD FOR IMPACT TOOLS 11 Claims, 4 Drawing Figs.

[52] 11.8. C1 173/131, 173/132, 145/29 [51] Int. Cl 325d 9/00, 1521b 1/00 [50] FleldoiSearch 173/131, 132,126, 127, 80; 81/523, 5235; 145/29 R, 29 A-29 D [56] References Cited UNITED STATES PATENTS 2,053,508 9/1936 Barney et a1 173/131 1 3k l8- ff- PATENTEUHUV 9 197i 3,618,678

ARTHUR J. 544/ TH /N VE N TOR A TTOPNEYS BACKGROUND OF THE INVENTION The invention generally relates to impact heads, and more particularly to an improved impact head having particular utility with hand-held impact tools.

The prior art includes numerous types of impact heads for use with various types of impact tools, including both pneumatically and electrically driven impact motors, guns and the like. Frequently, such impact heads are fabricated from metals, such as steel and aluminum, and in certain limited purposes impact heads have been fabricated from various synthetic resins or plastic materials. However, when employing synthetic resins, designers of such heads have faced several heretofore unsolved problems. These problems often arise from an inability to couple blocks of synthetic resin with suitable metallic base structures in a practical and economic manner. This apparently results from the fact that when such impact heads are employed with high-speed impact tools, the employed synthetic resin, when subjected to forces of shock and changing temperature, tends to flow with a consequential release of the metallic base. Hence, heretofore available impact heads, which are so formed as to include metallic base structures and impact blocks or synthetic resins, have not met with total acceptability in the trade, particularly where they are employed with tools of a type developed for high-speed impact operations, such as the tool disclosed in copending application Ser. No. 46,427, filed July 2, I970.

OBJECTS AND SUMMARY OF THE INVENTION It is therefore an object of the instant invention to provide an improved impact head.

It is another object to provide an improved impact head for use with manually manipulated, pneumatically driven impact tools.

Another object is to provide for use with a high-speed impact tool an improved impact head having a metallic core and a uniquely integrated impact block formed of a synthetic resin.

It is another object of the instant invention to provide an improved impact head for use with high-speed impact tools formed by embedding within an homogeneous mass of synthetic resin a metallic core including a base portion adapted to be coupled with an impact tool and a distal portion including a circumscribing rib having formed therein an annular array of tubular openings extending through the rib whereby the resin fills the openings and securely couples the core and mass in an integrated fashion.

These and other objects and'advantages of the instant invention are achieved by providing for use with an impact tool an impact head having a core formed from a lightweight metal so machined as to include an annular base portion circumscribed by a base rib, and an adjacent, coaxially related distal portion circumscribed by a terminal rib integrated, through an array of openings, with an impact block formed from an homogeneous mass of synthetic resin.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of the impact head which includes a metallic core and an integrated impact block formed of a synthetic resin and embodies the principles of the instant invention.

FIGS. 2 and 3 are partially sectioned views illustrating a manner in which a mass of synthetic resin is integrated with a metallic core to provide the impact head of FIG. 1.

FIG. 4 is a perspective view of the core shown in FIGS. 1 through 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIG. 1 an improved impact head which embodies the principles of the present invention.

The impact head includes a core embedded in an impact block 12 formed from a mass, preferably a homogeneous mass of hardened thermoplastic material such as that frequently referred to as an acrylic resin. The core 10 preferably is machined from aluminum stock material. Preferably, the core 10 is provided with an annular base 13, including a circumscribing base rib 14, of a given diameter, and a terminal portion 15, including a circumscribing terminal rib 16 of a diameter less than that of the diameter of the base rib 14.

The rib l6 coaxially is related to the base rib 14 and axially is spaced therefrom so as to provide therebetween an annular groove 18. The tenninal rib 16 is provided with an annular array of parallel tubular openings 20 which extend from the groove 18 and terminate in a transverse terminal face 22 provided at the distal end of the core 10. As best illustrated in FIG. 1, the terminal rib 16, along with its openings 20, totally is embedded within the impact block 12.

In order to embed the terminal rib 16 within the impact block 12, an injection molding process is employed. In carrying out this process, the base 13 of the core 10 is seated within a base portion of an injection mold of a clam-shell type, generally designated 24. The core 10 is seated in a manner such that the groove 18 and the terminal rib 16, with its array of openings 20, are extended into an appropriately configured cavity formed within a cavity portion of the mold 24. A suitable synthetic resin, such as an acrylic plastic is, in it fluid state, injected into the mold 24 through suitable conduits 26 and 28 in a manner consistent with injection molding techniques.

As a practical matter, the relative dimensions of the core 10 and the mold 24 are such that the diameter of the base rib 14 is greater than that of the cavity portion of the mold. Therefore, the base 13 is seated within the base portion of the mold in a manner that is a planer face of the base rib 14, adjacent to the. groove 18, communicates with the cavity of the mold. Consequently, the fluidized resin is delivered to abut the base rib 14 but cannot inundate the rib as the resin is injected into the cavity.

Since the specific mold employed forms no specific part of the instant invention, a detailed description is omitted. However, it is to be understood that the synthetic resin which is employed in facing the impact block 12 is delivered in its fluid state into the cavity of the mold 24, caused to abut the base rib l4, fill the groove 18 and the array of openings 20, and to surround the periphery of the rib 16 so that the rib is caused to be embedded in an homogeneous mass of fluidized resin. Once the resin has been cured, by employing suitable curing techniques, the mold 24 is opened and the impact head is removed and polished to provide a completed impact head.

Furthermore, it is quite important to understand that the synthetic resin, in its fluid state, is delivered to the mold 24 in a manner such that the resulting impact block 12 is an homogeneous mass having rootlike portions extending through the openings 20 into and integrally joining with the mass filling the groove 18. Consequently, each of the rootlike portions extending through the openings 20, in effect, forms an independent locking ring integral with the mass. Hence, a roll" and flow of the homogeneous mass is precluded, due to the rootlike portions extending through the openings 20, as the head operatively is employed.

As a practical matter, the core 10 also includes an internally screw-threaded, concentric bore 30. This bore serves to facilitate coupling the impact head with a screw-threaded coupling stem of an impact tool. Furthennore, an annular relief 32 is machined into a planer surface of the core 10 for purposes of receiving therein a base of a sleeve of a fluid discharge unit, not shown, frequently employed in impact tools.

In instances where the impact head is employed in tools of the type disclosed in the aforementioned copending application, an annular groove 34 is provided for receiving an O-ring which precludes passage of air about the periphery of the impact head for thereby facilitating an efircient operation of the impact head.

in view of the foregoing it should be readily be apparent that the instant invention is embodied in an improved, novel impact head which particularly is suited for use with hand-held, pneumatically operated impact tools, having particular environment wherein durability, weight, head momentum and protection of working surfaces is of prime concern.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the illustrative details disclosed.

Having described my invention, what l claim as new and desire to secure by Letters Patent is:

1. An impact head comprising:

A. a core having a base portion and an adjacent coaxially related distal portion terminating in a transversely related disc face;

B. a base rib circumscribing said base portion and a terminal rib circumscribing said distal portion adjacent to said distal face, said ribs defining therebetween an annular groove;

C. means defining an array of openings extended through said terminal, rib, whereby the distal face of said annular groove is caused to communicate through said array of openings;

D. a mass defining an impact block integrally related with said core and including a root portion filling the openings of said array and said groove, having a distal portion terminating in a transverse impact face spaced from the distal face of said body; and

E. means adapted to accommodate a coupling of the head with an impact tool.

2. The head of claim I wherein said core is formed from a lightweight metallic material and said mass comprises a mass of synthetic resin.

3. The head of claim 2 wherein said mass of resin is integrated with said body by placing the distal portion of said core within a cavity of a closed injection mold, injecting said resin into the mold and permitting the injected resin to cure.

4. The head of claim 2 wherein said terminal rib is embedded in said mass.

5. The head of claim 4 wherein said ribs are of an annular configuration and said array of openings comprises an annular array.

6. The head of claim 5 wherein the openings of said array conforms to tubular bores extended through said terminal rib.

7. The head of claim 4 wherein said base rib has an outside diameter substantially greater than the outside diameter of said terminal rib and includes a radially extended, annular face disposed in an abutting relationship with said mass.

8. The head of claim 7 further including means defining an annular groove circumscribing said base portion adapted to receive therein an O-ring.

9. in an impact head, means comprising:

A. a rigid core having an elongated body embedded in an homogeneous mass of hardened synthetic resin; and

B. means defining, within said body an opening extending through a portion of the body whereby said homogeneous mass of resin substantially fills said opening and communicates with said mass at opposite ends of the opening.

10. An impact head comprising:

A. a core having a base, a distal end, a circumscribing groove intermediate the base and said end and openings extended from the groove to the distal end; and

B. a mass of material bonded to the core and encapsulating the distal end thereof substantially filling said groove and openings and providing an integral exterior sheath from the groove to said distal end.

11. The head of claim 10 in which the core is of substantially rigid metal and the mass of somewhat malleable plastic material.

t 1! k i UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,618 678 Dated November 9 1971 Invenwfls) Arthur J. Smith It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 25, "or" should be changed to ---of---.

Column 2, line 26, "it" should be changed to ---its---;

line 34, --such--- should be inserted after "manner", "is" should be deleted, and

"planer" should be changed to --planar---;

line 66, "planer" should be changed to ---p1anar--.

Column 3, line 17, "disc" should be changed to ---distal--.

Signed and sealed this 18th day of April 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents ORM PO-1D5O 110-59) USCOMM- c 5 375 359 11 u 5 GOVERNMENT PRINTING orncz Iss9 O]66 JJ4

Claims (11)

1. An impact head comprising: A. a core having a base portion and an adjacent coaxially related distal portion terminating in a transversely related distal face; B. a base rib circumscribing said base portion and a terminal rib circumscribing said distal portion adjacent to said distal face, said ribs defining therebetween an annular groove; C. means defining an array of openings extended through said terminal, rib, whereby the distal face of said annular groove is caused to communicate through said array of openings; D. a mass defining an impact block integrally related with said core and including a root portion filling the openings of said array and said groove, having a distal portion terminating in a transverse impact face spaced from the distal face of said body; and E. means adapted to accommodate a coupling of the head with an impact tool.

2. The head of claim 1 wherein said core is formed from a lightweight metallic material and said mass comprises a mass of synthetic resin.

3. The head of claim 2 wherein said mass of resin is integrated with said body by placing the distal portion of said core within a cavity of a closed injection mold, injecting said resin into the mold and permitting the injected resin to cure.

4. The head of claim 2 wherein said terminal rib is embedded in said mass.

5. The head of claim 4 wherein said ribs are of an annular configuration and said array of openings comprises an annular array.

6. The head of claim 5 wherein the openings of said array conforms to tubular bores extended through said terminal rib.

7. The head of claim 4 wherein said base rib has an outside diameter substantially greater than the outside diameter of said terminal rib and includes a radially extended, annular face disposed in an abutting relationship with said mass.

8. The head of claim 7 further including means defining an annular groove circumscribing said base portion adapted to receive therein an O-ring.

9. In an impact head, means comprising: A. a rigid cOre having an elongated body embedded in an homogeneous mass of hardened synthetic resin; and B. means defining, within said body an opening extending through a portion of the body whereby said homogeneous mass of resin substantially fills said opening and communicates with said mass at opposite ends of the opening.

10. An impact head comprising: A. a core having a base, a distal end, a circumscribing groove intermediate the base and said end and openings extended from the groove to the distal end; and B. a mass of material bonded to the core and encapsulating the distal end thereof substantially filling said groove and openings and providing an integral exterior sheath from the groove to said distal end.

11. The head of claim 10 in which the core is of substantially rigid metal and the mass of somewhat malleable plastic material.

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