US 3766819 A
An anchor bolt including a cylindrical body having a reduced diameter portion near one end and an outwardly flaring portion extending from the reduced diameter portion toward that one end. A pair of expansion members encircle the reduced diameter portion. Each expansion member is a curved resilient element extending through an angle greater than 180 DEG , e.g. 220 DEG , and the expansion members have cooperable interlock means for transmitting axial movement of one expansion member to the other. The two expansion members may be identical to each other, and each may have an outwardly projecting protuberance. One or both of the reduced diameter and outwardly flaring portions of the body may have a non-circular, e.g., elliptical, cross-sectional shape.
Description (OCR text may contain errors)
United States Patent 1 [11.1 3,766,819 Giannuzzi Oct. 23, 1973  ANCHOR BOLT 259,211 4/1967 Austria 85/88  Inventor: Louis N. Giannuzzi, Riverside,
C Primary Examiner-Edward C. Allen Att0meyAlan H. Levine  Ass1gnee: Die Cast and Forge Company, Inc.,
New Rochelle, NY.  Filed: Dec. 3, 1971  ABSTRACT An anchor bolt including a cylindrical body having a reduced diameter portion near one end and an outwardly flaring portion extending from the reduced di-  U.S. Cl. 85/77, 85/88 ameter portion toward that one end. A pair of expan-  Int. Cl Fl6b 13/06 sion members encircle the reduced diameter portion.  Field of Search 85/77, 78, 79, 86, Each expansion member is a curved resilient element 85/87, 88, 51 extending through an angle greater than 180, e.g. a 220, and the expansion members have cooperable in-  References Cited terlock means for transmitting axial movement of one UNITED STATES PATENTS expansion member to the other. The two expansion 3 277 770 10/1966 Mccuuoch 85/77 members may be identical to each other, and each 3657955 4/1972 Mcxaymmxm 85/51 may have an outwardly projecting protuberance. One 8/1908 Capuw 85/77 or both of the reduced diameter andoutwardly flaring 1,495,497 5/1924 Ogden 85/88 po of the y y have a non-circular, -g-,
FOREIGN PATENTS OR APPLICATIONS cmss'sectmal shape 564,601 10/1958 Canada 85/88 9 Claims, 8 Drawing Figures A3) fl) ANCHOR BOLT This invention relates to anchor bolts of the type used to fasten articles to surfaces of masonry or like material. In particular, the invention relates to the type of anchor bolt carrying an expansion means near one of its ends.
When such an anchor is inserted into a bore drilled in a wall or other surface, its expansion means is in a contracted condition because it is located around the smallest diameter portion of the bolt body. The expansion means frictionally engages the wall of the bore so that as the bolt body is slowly withdrawn from the bore during the fastening operation, the body moves axially with respect to the expansion means. The axial movement brings a body portion of increased diameter into the expansion means, thereby expanding the latter and causing it to tightly engage the bore wall. As a result, the body is firmly anchored to the wall.
Anchor bolts of this type embodying various designs have been available for some time. However, each presents a problem from the point of view of manufacture, shipping, and/or use.
It is an object of the present invention to provide an anchor bolt of the type described above which is simple and inexpensive to manufacture and assemble, which will remain assembled during shipmemnt, and which is easy to use and reliable in performing its anchoring function.
It is a more specific object of the invention to provide an anchor bolt having two separate expansion members which can be readily assembled with the bolt body by hand, but which will nevertheless not become disassembled during shipment and use.
It is another object of the invention to provide such an anchor bolt in which the two independent expansion members are interlocked once assembled with the bolt body to insure that both expansion members participate in securing the body within a bore.
Additional objects and features of the invention will be apparent from the following description in which reference is made to the accompanying drawings.
In the drawings:
FIG. 1 is an elevational view of a bolt body forming part of an anchor bolt according to the present invention;
FIGS. 2 and 3 are cross-sectional views taken along lines 2-2 and 3--3, respectively, of FIG. 1;
FIG. 4 is an exploded perspective view of expansion members forming part of an anchor bolt according to the present invention;
FIG. 5 is an end elevational view of one of the expansion members;
FIG. 6 is an elevational view of an anchor bolt.according to the present'invention prior to use;
FIG. 7 is a cross-sectional view showing the anchor bolt within a bore in a concrete wall prior to expansion of the expansion members, the bolt body being shown in elevation; and
FIG. 8 is a view similar to FIG. 7 showing the expansion members in expanded condition as well as in elevation.
The anchor bolt chosen to illustrate the present invention comprises a bolt body 10 and two expansion members 11 and 12. Body 10 has a generally cylindrical shape, and is provided at one end with a screw thread 13. Although a screw thread is illustrated, this end of the bolt body could beprovided with a hook shape, or any other configuration by means of which an axial force can be exerted on the body to withdraw it from a bore into which it is placed.
Near its end 14, i.e., the end which is first inserted into a bore in which the anchor bolt is to be held, body 10 is formed with a reduced diameter region 15. Merging with reduced diameter portion 15 is a flaring portion 16 of the bolt body which tapers outwardly toward end 14.
Body 10 may have circular cross-sectional shape throughout its length. However, according to the invention, it is preferred that one or both of the reduced diameter portion 15 and flaring portion 16 have a noncircular cross-sectional shape. Preferably, portions 15. and 16 are elliptically shaped in cross-section, as shown in FIGS. 2 and 3. However, under certain circumstances it may be sufficient to make only one of these portions of elliptical shape.
For convenience of manufacture and assembly, expansion members 11 and 12 are identical to each other. Consequently, only one, namely, expansion members 12, will be described in detail, with reference to FIGS. 4 and 5.
In the present example, expansion member 12 is formed of sheet metal by means of a stamping operation, and hence it has a certain. inherent resilience. However, any other material having the strength and resilience characteristics required of the expansion members may be employed.
Expansion member 12 has an arcuate shape conforming closely to the shape of reduced diameter portion 15 of body 10. The main portion of member 12, i.e., the portion between longitudinal edges 19 and 20 extends through an arc of no more than and preferably slightly less than this angle. Extending peripherally from edge 19 is a finger 21. Formed in edge 20 is a peripheral notch 22 adapted to accommodate the finger 21 of expansion member 11. Notch 22 is spaced from both end edges 17 of the expansion member. The portion 23 of expansion member 12 on the side of notch 22 opposite edge 20 is peripherally extended, and the portion 24 on the side of finger 21 opposite edge 19 is cut back. Between the end edge 25 of finger 21 and end edge 26 of portion 23, members 12 extends through an angle greater than 180", this angle preferably being about 220. At its midportion, expansion member 12 is formed with an outwardly projecting protuberance 27.
To assemble expansion members 11 and 12 with bolt body 10, as shown in FIG. 6, the concave face of each expansion member is held adjacent to reduced diameter portion 15, and the expansion member is pressed toward portion 15. Due to the inherent resilience of the I expansion member material, finger 21 and portion 23 first move away from each other and ultimately snap over body portion 15. Since only the relatively narrow finger 21 and portion 23 are stressed during this assembly operation, the assembly can readily be performed manually. However, the gripping action of finger 21 and portion 23 upon reduced diameter portion 15 of body 10 is sufficient to maintain each expansion member assembled with the bolt body. It should be noted that this assembled condition is maintained without the use of any additional fastening means.
With the anchor bolt in assembled condition, finger 21 of each expansion member extends into notch 22 of the other expansion member. Thus, the fingers and notches serve as an interlock between the two expansion members, the purpose of which will be mentioned below.
The manner in which the anchor bolt may be used a illustrated in FIGS. 7 and 8. It is assumed that an article 30 is to be secured to a concrete wall 31. A bore 32 having a diameter slightly larger than the diameter of bolt body 10 is first drilled in wall 31.
The assembled anchor bolt is inserted into bore 32 with a portion of its threaded end 13 projecting from the bore. Article 30 is placed over the threaded end 13 and against the exposed surface of wall 31, and a nut 33 is threaded'onto bolt end 13.
As nut 33 is rotated, bolt body 10 is gradually withdrawn from bore 32. However, the frictional engagement between ex-pansion members 11 and 12 and the wall of bore 32 hinders with-drawal of the expansion members. This action is augmented by the presence of protuberances 27 which engage the wall of bore 32 and effectively prevent withdrawal of the expansion members.
As bolt body 10 moves axially toward the left in FIGS. 7 and 8, flaring portion 16 of the bolt body enters between expansion members 11 and 12, as shown in FIG. 8, thereby expanding them, i.e., moving them radially away from each other. This action tightly presses expansion members 11 and 12 against the wall of bore 32, and ultimately the expansion members prevent any further withdrawal, i.e., leftward movement of body 10. Bolt body 10 is therebyfirmly anchored in wall 31, and article 30 is securely mounted on the wall.
It sometimes happens that when two expansion members are employed, as in the present invention, one of them may grip the wall of bore 32 before the other end and thereby prevent the other from ever tightly gripping the wall of the bore. As a result, the holding power of the anchor bolt is greately reduced. This possibility is prevented by the interlock provided between the expansion members of the present invention. It will be seen that when one of the expansion members 11 or 12 grips the wall of bore 32, and hence begins to move axially with respect to bolt body 10, finger 21 of the expansion member which has gripped the wall will engage portion 23 of the other expansion member and cause it also to move with respect to body 10. Consequently, both expansion members will simultaneously be acted upon by flaring portion 16 and pressed tightly against the wall of bore 32.
It has been found with some conventional anchor bolts that as nut 33 is rotated, bolt body 10 rotates with the nut and hence the bolt body'never becomes anchored. The reason is that the portions and 16 of the bolt bodyare rotating inside the stationary expansion member. By making one or both of body portions 15 and 16 non-circular, as described above, this possibility is avoided.
The invention has been shown and described in'preferred form only, and by way of example, and many variations may be made in the invention which will still be comprised within its spirit. It is understood, therefore, that the invention is not limited to any specific form or embodiment except insofar as such limitations are included in the appended claims.
What is claimed is:
1. An anchor bolt comprising:
a. a cylindrical body having a reduced diameter portion near one end, and an outwardly flaring portion extending from said reduced diameter portion toward said one end, and
b. a pair of expansion members mounted on said reduced diameter portion, said expansion members being separate and independent of each other,
I. each of said expansion members being a curved resilient element having a portion which extends in a circumferential direction through an angle greater than l, whereby each of said members may be manually snapped over said reduced diameter portion and will remain thereon without the need for additional fastening means, and
II. each of said expansion members having interlock means cooperable with interlock means on the other ex-pansion member for transmitting movement of each of said expansion members, axially in both directions with re-spect to said body, to the other of said expansion members, said interlock means permitting separation of said expansion members in a radial direction, and said interlock means including a finger extending peripherally from one longitudinal edge of each expansion member and comprising a part of said expansion member portion which extends for more than and a peripheral notch in the other longitudinal edge thereof spaced from both end edges of the expansion member and adapted to accommodate a like finger of the other expansion member, the corresponding side edges of each said finger and notch being parallel and each said finger and notch being about equal in width so that each said finger fits snugly within its respective notch.
2. An anchor bolt as defined in claim 1 wherein said expansion members are identical to each other.
3. An anchor bolt as defined in claim 1 including a protuberance projecting radially outwardly from each of said expansion members.
4. An anchor bolt as defined in claim 1 wherein each of said expansion members extends through an angle of approximately 220.
.5.- An anchor bolt as defined in claim 1 wherein said reduced diameter portion of said body has a noncircular cross-sectional shape.
6. An anchor boltas defined in claim 5 wherein said reduced diameter portion has an elliptical crosssectional shape.
7. .An anchor bolt as defined in claim 1 wherein said outwardly flaring portion of said body has a noncircular cross-sectional shape.
8. An anchor bolt as defined in claim 7 wherein said outwardly flaring portion has an elliptical crosssectional shape.
9. An anchor bolt as defined in claim 1 wherein said reduced diameter and outwardly flaring portions of said body both have elliptical cross-sectional shapes.