US2884969A - Hammer construction with shock absorbing means - Google Patents

Description

May 5, 1959 c. M. LAY 2,884,969

HAMMER CONSTRUCTION WITH SHOCK ABSORBING MEANS Filed Aug. 25, 1957 3| 3o 3e 3e 8 54 Fles L Y INVENTOR': FIG-4 '4 CLARENCE MLAY y" user. "phase impact is applied to the hand of theuser by vvirtue United States Patent O HAMMER CONSTRUCTION WITH SHOCK ABSORBING MEANS Clarence M. Lay, Bushnell, Ill., assignor to Vaughan & Bushnell Mfg. Co., Bushnell, Ill., a corporation of Illinois Application August 23, 1957, Serial No. 679,833 3 Claims. (Cl. 145-29) The present invention relates to portable impact tools and has particular reference to a hammer construction.

The invention has been illustrated and described herein in t connection with the formation of a carpenters claw hammer and it is to this type of hammer that the invention is particularly applicable. The invention may, however, find use in connection with other impact tools, as for example, machinists hammers, blacksmiths hammers,`

bricklayers hammers and similar tools. The invention is specifically concerned with the construction of hammers of the so-called indestructible type having a steel shank which is integral with the striking head thereof.

In recent years there have appeared on the market claw hammers in which the handles or Shanks are formed of steel and are integral with the hammer heads, such hammers to a limited extent supplanting or more aptly supplementing the widely known and used hickory handle claw hammer. These indestructible hammers, as currently constructed, olfer a few advantages over conventional wooden handle hammers but they are also possessed of numerous limitations. Chief among the advantages afforded are increased strength and a permanent union be-^ Similarly, a wooden hammer handle will, in time, dry outk and become subject to looseness, splitting, or to`shearing forces at its region of juncture with the impact head while, obviously, such limitations are not attendant upon the use of integral steel hammer Shanks. These factors, together with the fact that indestructible type hammers possess design possibilities whereby they may be made in a variety of attractive styles possessing eye-appeal, are ascribed as possible reasons why such hammers have met with a modicum of success on the market.

On the other hand, indestructible hammers of the type briefly outlined above and as presently manufactured are possessed of numerous limitations, principal among which are lack of resiliency which renders them awkward in the hand of an experienced carpenter or workman; the tendency for impact to set up undesired harmonic vibrations; the `inability under prevalent manufacturing processes to produce a hammer assembly of correct or accepted proportions and balance; and the large number of operations which are required to produce the combined head, claw and shank unit of the hammer assembly.

lnasmuch as these indestructible type hammers are inj variably formed with a solid steel head, claw and shank unit, the force of the impact is carried directly from the head and into the shank where it is felt by the hand of the At the same time a secondary and slightly out-of- `the desired point of impact.

Patented May 5, 1959 fice of the initial shock traveling across the hammer head and into the hammer claw which is caused to vibrate and send a secondary impact back to the shank following closely on the heels of the initial and somewhat stronger impact force. Thus the solid steel construction of such hammers as currently manufactured does not atford the shock absorbing resiliency of conventional hickory handle hammers.

Due to the greater density and weight of steel as compared to wood, these solid steel indestructible types of hammers are not balanced properly, which is to say that they are handle-heavy and cannot successfully be subjected to the usual tests for proper balance. The art of constructing hammers, particularly carpenters claw hammers is an exacting one. In few other arts does such a little difference make such a big difference. The term balance is not readily delinable, but it may be stated that a properly balanced hammer, particularly a carpenters claw hammer, is one which in the hands of an experienced carpenter gives him a sense of satisfaction and confidence in his manipulation of the tool. It is one which is easily aimed and will lind impact squarely at A hammer which is not properly balanced feels awkward or heavy in the hand of the experienced user and in swinging the same, centrifugal and other forces are set up which give an unnatural feeling to the user just as does an improperly balanced golf club or tennis racket to the expert. One test for proper balance commonly employed by prospective purchasers of conventional sixteen ounce hammers is to place the hammer head down, on a at level surface, allowing the weight of the hammer to be borne on the curved surface of the claws near the base thereof so that the hammer assumes a rocking position on this curved surface with the handle extending upward at au acute angle with respect to the ilat supporting surface. Then, if the hammer is capable of assuming a stable degree of equilibrium, this is an indication of proper hammer balance. On the other hand, if the hammer cannot be thus supported and instead it possesses an unstable degree of equilibrium, this is an indication that the hammer is not properly balanced. So far as is known, present day solid head and shank indestructible hammers are incapable of passing such a test.

Present day indestructible hammers of the type briefly outlined'above will vibrate after impact, the vibration being accentuated in the claw region of the hammer. Not only is such vibration unpleasant to the sense of touch but repeated vibration over a long period of time sets up stresses in the body of the hammer in the vicinity of the claw which, in time, weakens the metal in this region so that upon a subsequent occasion when the claw is used for leverage purposes, one or both claws will break away from the head.

Although hammers are made in various sizes, and although the proportions of the various constituent parts of a hammer may vary Widely, a standard carpenters claw hammer usually has a 16 ounce head and a handle which is of the order of slightly greater than 13 inches in length. The overall longitudinal extent orlength of the hammer head is approximately five and one half inches. Any material deviation from these dimensions or from such weight of the hammer head will not be tolerated by a carpenter. These dimensions and hammer head weights are applicable to both wooden handle hammers and to indestructible type hammers. For these reashape as between the indestructible type hammer and the conventional wooden handle hammer. However, manufactoring difliculties arise which have heretofore prevented the indestructible type of hammer from being a substantial replica of the wooden handle hammer insofar oS .Shape .and weight are concerned and. manufacturers have been obliged to effect a compromise in the proportions of indestructible type hammers. Due to the fact that integral head and shank type hammers are solid and are devoid of the usual hollow eye into which the Wooden handle is inserted and in which'it is anchored, the additional metal involved, if the same shape and dimensions are to be preserved, will lead to the construction of a hammer having a head which is materially overweight. In other words, an indestructible type hammer having a solid metal head of the same shape and head of a Wooden handle claw hammer with a 16r ounce head will have a head Whioh weighs approximately 2,0 ounces. For this reason, indestructible type hammers are currently mennfaotnred eo that the heads thereof are approximately 16 onnoes in Weight hut have the Size and Shane the equivallent of the Size and shape of a Wooden handle claw ham- ;,Inerthe head of Whieh is 1.3 ounces- Finelly. voonventional forging processes-do not klend themselves readily to the eonetrnetion of one-piece 'nte- .giel head. and Shank. .type hnrmnerse Whereme headand M ShenkV are `forged together. the operation oalls for the use .of relatively deep drawing operations utilizing dies of ,Considerable depth Furthermore, multi-Stage forging operations are required to shape the handle region of the hammer and these are followed by auxiliary pressing and other shaping operations which are costly procedures and materially increase the cost of the article.

The present invention `is designed to overcome the above noted limitations that are attendant upon the construction and use of indestructible type hammers of the general character heretofore set forth, as well as to overcome the manufacturing difliculties attendant upon the production of such hammers. Toward this end, the invention contemplates the provision of a novel form of functionally integral head and shank unit which, when assembled in a hammer construction,` affords a degree of resiliency which gives to the hammer as a whole improved shock-absorbing qualities which hitherto have been unattainable in connection with the manufacture of indestructible type hammers.

The provision of a hammer of this sort having proved shock absorbing qualities as stated above being among the principal objects of the invention, it is another object to provide an indestructible hammer which compares favorably with conventional hammers of the wooden handle type insofar as its balance is concerned and which is acceptable in this respect lby the average carpenter or other workman.

Another ohieot of the inventionl is. to provide an indei structible hammer of sort having associated-therewith` dampening means whereby undesired harmonic vibrations are substantially eliminated so that there will be no weakening of the metal of the hammer under continued use thereof.

Yet another object of the invention is to provide an indestructible hammer of one-piece head and shank construction which lends itself to mass production by drop forging operations yet which, at the same time, will cause such a distribution of metal during the forging process as to produce a hammer of correct kor accepted proportions, as outlined above, and of the proper Weight, particularly insofar as the weight of the head portion per se is concerned. t

Another and important object of the invention is tov provide a novel indestructible hammer of the unitary head and shank variety which possesses the vadvantageous features briefly outlined above and which, in the manufacture thereof, makes` possible the elimination of .a large number of shaping operations which are ordinarily-required in the production of hammers of this sort, the various operations involved being of a relatively simple inature and requiring no special skill on the part of the` operator, the process as a whole being conducive toward uniformity in the manufacture of the hammers. i I

vIn carrying ont this lnstrnentioned object of the i11- vention, it is contemplated that the head portion of the hammer including the impact head proper and the claw, together with a limited portion or extent of the shank, be constructed as a single unit by a process involving an initial drop forging operation, followed by a trimming operation and a subsequent nal pressing operation which results in the production of the head portion of the hammer and a limited extent of the shank portion thereof in substantially its completed form. The remainder of the shank portion of the hammer is separately formed by a simple forging operation and, thereafter, the die formed portion of the shank is butt welded to the head so that it forms a continuation of the shank extension on the head and finally, smoothing operations are performed to produce the finished head and shank unit. By such a process, deep drawing operations are avoided and the cost of the dies involved is materially reduced. Additionally, intricate shaping operations involving the use of skilled laborare eliminated, and a high level of production atfa reasonable eost may be attained.

Other objects and advantages of the invention, not-at this time enumerated, will become more readily apparent as the nature of the invention is better understood.

In the accompanying one sheet of drawings forming a part of this specification, a preferred embodiment of a carpenters claw hammer constructed in accordance with the principles of the present invention has been illustrated and the method by means of which the hammer is constructed has been portrayed in somewhat schematic fashion.

In these drawings:

Fig. 1 is a side elevational view of a carpenters claw hammer constructed in accordance with the principles of the present invention with certain parts being broken Way to more clearly reveal the nature of the invention.

Fig. 2 is a front elevational view of the structure shown in Fig. 1.

Fig. 3 is an exanded side elevational view of forged head and shank section units respectively, illustrating schematically the manner in which these units are joined together to produce a unitary hammer assembly.

Fig. 4 is a fragmentary end View of the hammer shown in Figsl and 2,.

Fig. 5 is a sectional view taken substantially along the line 5-.5 of Fiel 4, and

Fig. 6 ais a sectional view taken substantially along the line 6.-:6 of Fig- 2 Referring ,now to the drawings in detail and in particular to` Figs. l, Zand 4, the improved tool comprising the present, invention has, for exemplary purposes, been illustrated herein as being in the form of a carpenters claw hammer of the indestructible type and which, for purposes of discussion herein, is of more or less standard dimensions, i.e. it is provided with a sixteen ounce head, a thirteen inch shank and has a longitudinal spread across the head portion of tive and one-half inches. While other dimensions and weights are contemplated, the Weights and dimensions mentioned above will, if adhered to, provide a hammer which is generally acceptable to carpenters and similar tradesmen.

The hammer head is designated in its entirety at 10 and is integral with the handle shank 12. The head 10 in the illustrated form of the invention is of the bell-faced type and includes a cylindrical impact head proper 14 having a circular impact surface 16. The impact head proper 14 is connected to one side of the medial body portion 1,8 by a constricted portion 20 which is polygonal in cross section and the other side of the body portion 18 is connected to the claw region 22, the latter region being bifurcated as at 24 to provide the usual diverging claws 26. The shank 12 merges with the head 10 along gradually formed curved surfaces 28 as is customary in the formaltion of these indestructible type hammers. The medial ybody portion 1,8 ofthe hammer head -10 isV formed with a relatively deep socket 30 therein which is generally rectangular in cross section as seen in Fig. 4 and the four walls 31 of which converge inwardly toward each other` in the outer regions of the socket. The bottom wall of the socket is slightly dished as shown at 32 in Figs. 1 and 3. The provision of the socket 30 constitutes one of the important features of the 'present ,invention and its nature and function will be more fully described hereinafter.

The shank 12 is comprised of a proximate grip section 34 and a distal connecting section 36 by means of which the grip section is operatively connected to the head 10. The distal section 36 is generally elliptical in transverse cross section, the ellipse having a relatively short minor axis and a relatively long major axis so that this portion of the shank is relatively thin in the transverse direction of the hammer as a whole. The proximate grip section 34 is generally at and the longitudinal side edges thereof are formed with marginal ribs 38 so that the section is generally H-shape in cross section.

The grip section 34 is adapted to receive thereover a tubular handle proper or sheath 40 (Figs. 1, 2 and 6) which may be formed of any suitable material but which is preferably formed of a material having good shock absorbing qualities as for example an elastomeric material such as rubber, either natural or synthetic, a rubber substitute or the like. It is also contemplated that the sheath 40 may be formed of turned leather or of a suitable plastic material. The sheath 40 is formed with a relatively deep socket 42 therein (Fig. 6) and into which the grip section 34 of the shank 12 may be inserted by telescoping the sheath 40 over this portion of the shank during the final assembly of the hammer. A pair of oppositely disposed T-shaped slots 43 are formed in the wall of the sheath to receive the marginal ribs 38 and, when the sheath 40 is fully received on the grip portion 34, the web portion of the latter extends across the socket 42 with clearance regions 41 existing between the wall of the sheath and the web part of the grip portion. The specific nature of the sheath 40 forms no part of the present invention and no claim is made herein to any novelty associated therewith, such a sheath being shown and described in my co-pending application Serial No. 685,187, led on September 20, 1957 and entitled, Handle Construction for Hammers and Similar Impact Tools.

The rectangular socket 30 provided in the medial body portion 18 of the hammer head 10 may be left exposed so that it assumes the appearance which it has when it emerges from the shaping operation in the manufacture of the head portion of the hammer as seen in Fig. 3, but preferably this socket 30 is filled with a vibration dampening substance such as a suitable thermoplastic or thermosetting material as indicated at 44. Alternatively, it may be filled with a hickory plug which, if desired, may be concealed by an outer veneer of the plastic material.

The hammer construction described above is possessed of good shock-absorbing qualities, has proper balance, and is not subject to extreme harmonic vibration, besides possessing all of the advantageous features of conventional indestructible type hammers such as strength, rigidity, hammer, shank unity, etc. These former attributes of the hammer are, to a large extent, made possible by the provision of the socket 30.

Insofar as the shock-absorbing qualities of the hammer are concerned, it is to be noted that the four Walls 31 of the socket 30 are of relatively thin construction, especially in the base region thereof. Thus, any impact shock which is applied to the hammer head proper 14 will be transmitted through the reduced neck portion 20 to the relatively thin side walls 31 of the socket 30. Much of this impact shock will be dissipated in these side walls and only a limited portion thereof will be conducted from the side walls to the shank portion 12. A limited portion of this impact shock will also be transmitted through the .side walls 31 to the claw portion 22 where, in the absence of the filler material 30, a relatively small amount of vibration may be set up in the claw but the extent of such vibration will not be nearly as great as in the case of an indestructible hammer having a solid head devoid of the rectangular socket 30. When the socket 30 is lled with a vibration-dampening substance such as the plastic material 44, the duration of any harmonic vibration set up in the claw region 22 will be materially reduced, much in the manner that the vibrations of a tuning fork or a resonant bell are effectively dampened when the hand is applied thereto. By such an arrangement, prolonged harmonic vibration of the claw region 22 is prevented and there will be no structural weakening of the metal of the claw region as is the case in connection with solid head hammers. Furthermore, reduction in the vibrational effects of the claw portion 22 will materially reduce any secondary impact shock which may be transmitted from the claw to the shank 12.

Proper balance of the hammer assembly is made possible by virtue of the fact that the space consumed by the socket 30 possesses no metal mass and therefore adds no weight to the body of the head. The head may thus be constructed along conventional lines insofar as its shape and size is concerned and a full sixteen ounce head and claw unit may be made to have. the usual ve and onehalf inch longitudinal spread.

The method involved in fabricating `the above described indestructible type hammer forms the subject matter of my copending application, Serial No. 739,930, tiled on June 4, 1958 and entitled, Method of Forming Indestructible Type Impact Tools, and reference may be had to such application for a full disclosure of such method. Certain phases of this method are illustrated herein in Fig. 3 wherein the head portion 10 in its entirety and a limited extent of the shank 12 are shown as being formed as a single integral unit while the remaining portion of the shank is shown as being formed as a separate unit. The two units are then joined together by a butt welding operation at a region designated at 50 in Fig. l to produce the one-piece hammer construction, after which the handle grip 40 is applied to the shank 12.

The invention is not to be understood as restricted to the details set forth since these may be modified within the scope of the appended claims without departing from the spirit and scope of the invention.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

l. In a claw hammer, an integral one-piece steel head and shank assembly including a head portion from which there projects outwardly and elongated shank portion the free end region of which constitutes a handle for manipulation of the hammer, said head portion being formed with an impact head proper at one end thereof, a claw portion at the other end thereof and a medial body portion from which said shank portion extends outwardly, said medial body portion having substantially at sides and being formed with a relatively deep socket which is rectangular in cross section and the axis of which is in alignment with the longitudinal axis of said shank portion, said socket being of such depth that it extends completely through said head portion and into the adjacent end of the shank portion, the side walls of said socket being relatively thin whereby they are suciently exible to absorb a major portion of the impact shock of said impact head proper.

2. In a claw hammer, an integral one-piece steel head and shank assembly including a head portion from which there projects outwardly an elongated shank portion the free end region of which constitutes a handle for manipulation of the hammer, said head portion being formed with an impact head proper at one end thereof, a claw portion at the other end thereof and a medial body portion from which said shank portion extends outwardly, said medial body portion having substantially llat sides which are inclined toward each other in the direction of said shank portion'and-'being formed with a relatively de ep socket which is-rectangular in cross section and the axis of which is in alignment with `the longitudinal axis of 4said shank portion, said socket vbeing of such depth that it extendsfcompletely through said head portion and into 'the adjacent end of the shank portion, said socket being filled with a vibraton'dampening substance.

3. In a claw hammer, the combination setforth :in claim 2 Awherein said vibrationdampening substance-is :comprised of a hardened plastic material.

Retereneesited in Vthstlc of this'rpatent UNITED STATES PATENTS `Hose Aug. 4, v Estwin'g Apr. 2, Heinrich -e Oct. 12, Bstwing Oct. 16, Floren Iuly 15,

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