US2154012A - Rivet - Google Patents

Description

April 11,A 1939. A. RHODES;

RIVET Filled Jan. 17, 195e ,lm Zilli!!! Patented Apr. 11, 1939.

` UNITI-:o STA-'rss inver Austin D. nimes, Waltham, una, nunmto Judson L Thomson Manufacturing Company,

' Inc.,"Waitham, Mass.,

achusetts va corporation of Maasapplicati@ .raum-y rz, raadsel-lai No. 59,535

1Claim.

This invention relates to rivets and more par ticularly to what are called compression rivets, which are made in two parts, namely, a tubular .member and a plug adapted to be forced into the 5 bore of said member.

The type of rivets of this character heretofore and now in use is shown and described in United States Letters Patent No. 749,438, issued January l2, 1904 to Charles D. Harrington. These rivets have principally been used for fastening separate parts together, such, for instance, as handle portions to the shank of a knife, the parts being provided with suitable holes for receiving the rivet members which generally have expanded heads for engaging the outer surfaces of the parts. The two members of the rivet are fas-A tened together by driving the plug-into the bore of the tubular member. 'Ihe diameter pf the bore is slightly less than the diameter of the plug which is provided with a tapered end for entering the bore, and the frictional t between the two members, due to this difference in diameter, is relied upon to prevent the two members of the rivet from separating under strain.

Enormous quantities of these .rivets are used annually inthe knife and tool makingart, which is an extensive and important findustry. For lcheap work, the rivets are made of brass, but in the higher grades of work where a better finish is required, nickel silver or other similar material is used. For many years, however, the in dustry has suffered from the fact that it has been 'impossible to get-uniform results'in the use of such rivets and rivet manufacturers have, hereand to produce rivets of'uniform strain-resisting v power. v

' In 'the use of brass rivets, for instance, it has been found in many cases that a comparatively manufacturers, in order to test the `holding power of these rivets, to hold the'knife by the end of 45 the blade and t0 strike the blade 'near the han'- dle a sharp blow against the edge of the workf 55 rivets bave'be'en made, 'which has increased the tofore, been unable to overcome this objection slight strain is sumcient to cause the two members of the rivet to separate and theparts held thereby to come apart. Itis customary for knife ('Cl., Sil-344) lack of uniformity in the 'of the rivet. r

Various attempts have been made to eliminate this difiiculty. The rivet manufacturers, for instance, have reduced the diameter of the bore in the tubular member, in order to produce a stronger frictional grip between the two members of the rivet, but such attempts have created a worse dimculty, namely, the frequent splitting of the tubular member. In other cases, knife strain-resisting power manufacturers have adopted the expedient of putting the plug members in a tumbling machine with powdered emery dust in order to coat them with this dust and, thereby, to secure a rmer grip between the'two members, and this method is in vogue in many places today with the old form of rivet.v While it tends to improve the holding of the. rivets, it does not entirely eliminate the dimculties heretofore experienced.

Considerable dimculty has also been encounltered in the use of, such rivets when made of nickel silver because of the hardness of that material. It has frequently happened, when the plug has vbeen driven into the restricted bore of the tubular member, that the end of 'the latter shaves the plug to form a burr at the mouth of the tubular member, which reduces the diameter of the plug and destroys the grip between the two members.

Again, trouble has been experienced in the use of compression rivetsdue to the fact' that the plug is sometimes' shorter` than the length of the bore in the tubular member. There is more or less variation in the thickness of the handle portions, and, in the case of thin -pormember iu order to bring the heads of the two members flush with the outer faces of the handle portions, and this frequently results in the head of the plug being overdriven against the endof the tubular member, which causes that plug. At the same time, the overdriving'of the plug lfrequently results in a splitting of the handle portion, which is generally of hard wood and of the same lengthas the inside length of the `bore of the tubular The foregoing troubles have been more or less intermittent in this industry for many years but they crop up with such frequency as to be a Amore or less constant source of annoyance and expense to both the rivet and the tool manufacturerl. Up to the present time.. the rivet man- .member to balloon and to release its grip on the tions, the plug is driven further into the tubular splits easily. This diiiicultyhasbeen experienced to some extent even when the plug member is a ufacturers have been unable to produce rivets which could be used with uniform satisfactory results and which were not open to some, if not all, of the foregoing objections.

6 The main object of my invention is the provision `of a compression rivet having features of form and construction which eliminate all the foregoing difficulties.

Another object of the invention is the provil sion of a rivet in which the grip between the two parts is of uniform character and is suillciently strong to withstand all of the strains to which it may be subjected in use.

Other objects of the invention will be set forth l hereinafter.

My invention contemplates a rivet of the character described, having a number of novel features of construction which are productive of results not heretofore attained. One of the $0 important features of my invention resides in enlarging the bore in the tubular member for a short distance inwardly from its open end sufiiciently to receive the end of the plug without resistance. 'Ihe remaining and greater portion Il oi' said bore is made of smaller diameter than has heretofore been possible without incurring the frequent splitting of the tubular member when the plug is driven into the bore.V I have found that this feature produces a rivet of a unil0 form and permanent holding power sufficiently strong to resist all the strains incidental to use.

Another important feature of `my invention consists in making the plug slightly longer than the 'length of the bore, which eliminates all $5 possibility of ballooning the tubular member by overdriving and destroying the holding power of the rivet. In the case of thin handle portions, the head of the plug will project above the outer face of the handle which will be notice to the 0 operator to use a shorter rivet. This feature also avoids splitting of the handle portions.

Another feature is the provision of an inclined or beveled shoulder between the enlarged and restricted portions of the bore, which eliminates .a any shaving of the tubular member when the rivets are made of very hard material such as nickel silver.

In the accompanying drawing illustrating the invention; Figure l is an exploded side elevation of two parts of a rivet constructed in accordance with my invention;

Fig. 2 is an exploded central vertical sectional view of the same;

Fig. 3 is a vertical central sectional view of the u two parts of the rivet with the plug member partially inserted in the tubular member;

Fig. 4 is a similar view showing the two parts of the rivet in final assembled form; and

Fig. 5 is a side elevation. partly in section, of 00 a knife, showing the handle portion fastened to the knife blade by the use of rivets made in accordance with my invention.

In the drawing, the rivet is shown as made in two parts, a tubular member It and a plug member I2, both of which have solid expanded heads i4 and il respectively'. The bore of the tubular Ymember il is divided into a long portion Il of restricted diameter and a short portion 2l of enlarged diameter at its open en d, the two por- 70 tions being joined together by an annular beveled or inclined shoulder 22.

76 found that this result may be attained by mak- The said enlarged portion 2lv should be of a length just sumcient and no more 4to hold the plug in proper relation l, to the tubular member for driving and. I have ing the length of the enlarged portion equal to approximately one-sixth of the total length of the bore. 'Ihe plug member i2 is of uniform diameter except its end which has a very short taper 24 to facilitateits entrance overv the in- 5 clined shoulder into the restricted portion i8 of the bore in the tubular member. In length, the plug I2 is slightly longer than the length of the bore, so that when it is driven its full length into the bore, its head will not engage the end of the 10 the latter fits within the former, but not so snugly as to develop any appreciable amount of friction when the plug is moved through said portion. 'Ihe presence, however, of this enlarged portion permits the restricted portion of the bore g5 to he of smaller diameter than heretofore possible without incurring the risk of splitting the tubular member and I have found, for instance in the ordinary size of brass rivets, that the restricted portion of the bore may be reduced from three to six thousandths of an inch below the size of bore heretofore used in the old style of rivets. I have found that with this reduction in the diameter of the bore in this size of rivet that I obtain an astonishing increase in the holding power of the rivet so that even in the softest material, it will withstand all strains imposed by use, and, more important yet, these results are uniform.

For instance, I have found from numerous tests that with a plug of approximately one hundred and twenty-one thousandths of an inch in diameter and a tubular member having an out.- side diameter of approximately one hundred and forty thousandths of an inch and a restricted bore of a diameter of approximately one hundred and one and one-half thousandths of an in ch, which is live thousandths of an inch smaller than the bore of the-old style rivet, I get a rivet which will resist strainsup .to two hundred and fifty pounds, which is far in excess of any strain to which the rivets will be subjected in actual use. Furthermore, I find that these resuits Aare uniform.

It is further to be observed that owing to the presence of the enlarged portion of the bore in the tubular member and the inclined shoulder connecting it with the restricted portion, that the bevel on the end of the plug may be made extremely short, which eliminates any tendency 50 toward a conical formation in the bore of the tubular member when the two parts are driven together. In the old style of rivet, in order that the end of the plug might project into the end of the tubular member, a sufficient distance to insure straight driving, it was necessary to provide the end of the plug with a long bevel, which resulted, when the two parts were driven together, in a conical formation. ofthe bore through a relatively large portion of its length. This obviously weakened the grip between the two parts. Numerous tests of the old style rivet have demonstrated that the grip between the two parts is. frequently broken when they are separated a sixty-fourth of an inch or less and the ordinary size of lrivet should be approximately one thirty-second of an inch longer than the bore. -When the plug and bore are equal in length, anyvoverdriving of the plug, which may be due to a thin handle and the desire of the.

' operator to drive the two parts of the rivet together until the heads are ilush with the outer v faces of the handle, will tend to shorten the plug, and, thereby, cause ballooning, destroying the grip between the two. To eliminate this; 'someA manufacturers have adopted the expedient of using shorter rivet members which cannot be driven together for their full length, but this materially reduces the length of the grip between the members and their strain-resisting capacity and results in a much weaker rivet. When the plug is approximately one thirty-second of an inch longer than kthe bore, this excess of length will take care of any shortening of the plugdue to overdriving, and, thereby, will eliminate all possibilities of ballooning from overdriving.

In the use of rivets made in accordance with my invention, the plug member I2 is forced vor driven into the bore in the tubular member I0, in which operation the -end of the plug passesg through the enlarged portion 20 of the bore without resistance until its tapered end enters over the inclined shoulder `22 into the restricted portion i8 of the bore. The continued driving of the plug into the restricted portion causes the tubular member to be expanded and the 'plug to beslightly reduced in diameter, as shown in Figure 4 of the drawing, with the result that a very tight grip is set up between the plug and Atubular members. This grip is extended r to the enlarged portion 24 ofthe bore, due to the owage of metal downwardly to the base of the plug. This tendency of the metal to ow during'f the driving operation is especially noticeable in the case of rivets made ofthe softer materials,

l such as brass, and results in extending the gripping action between the two parts of the rivet the entire length that the plug is inserted into the tubular member.

In Figure 5, there is shown a knife blade 30 having handle portions 32 and 3l fastened to its shank by rivets made in accordance with my invention. The knife shanknand handle vpor-- tions are provided with suitable holes for receiving the rivets with suitablecountersunk portions in the outer faces of the handle portions for setting the heads of the parts of the-rivets iiush with said outer faces. In fastening the parts together, the tubular members are inserted in the holes in one side of the handle and the plugs are then placed in the holes in the other side of the handle with their ends inserted in the enlarged portions/of the bores of the tubular member and are then driven into the tubular Y member in any suitable manner, either with a hammer or with a pressing machine.

It is to be understood that my invention is not to be limited to the exact form herein shown and described, nor to the exact proportions of the parts stated, since it may be embodied in various other forms of construction with different proportions, all within the scope of the following claim. d

What I `claim is: A rivet for fastening handle portions to knife shanks and similar uses comprising a metallic female member having a head at its outer end and a tubular shank extending inwardly therefrom, said shank having an elongated bore of substantially uniform diameter extending from a point adjacent said head to a point intermediate of the latter and the inner Aend of the shank, and an enlarged bore extending from said inner end of the shank to the inner end of said rst gated binding impinger'nent between said male and female members and flowage of the metal of the latter, the enlarged bore portion of the female member affording space between the same. and the stem of the male member to accommodate said flowage of metal and create a continua- -tion of the binding imp'mgement vbetween thetubular and stem portions when driven together, the remote location of the juncture between the f relatively larger and smaller bores of the tubular shank effecting initial expanding forces between the stem and tubular portions substantially away from the inner end of the latter to avoid split- AUSTIN D. RHODES.

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