US3491648A

US3491648A - Anchoring element construction

Info

Publication number: US3491648A
Application number: US770759A
Authority: US
Inventors: Elmar Thurner
Original assignee: Hilti AG
Current assignee: Hilti AG
Priority date: 1967-11-13
Filing date: 1968-10-25
Publication date: 1970-01-27
Anticipated expiration: 1987-01-27
Also published as: DE1625367A1; FI48380C; FR1591475A; DE1625367B2; AT296180B; FI48380B; GB1235870A; SE350104B

Description

Jan. 27, 1970 THURNER ANCHORING ELEMENT CONSTRUCTION -2 Sheets-Sheet 1 Filed Oct. 25, 1968 Fig 1 lNvENToR ELMAR momen ANCHORING ELEMENT CONSTRUCTION Filed Oct. 25, 1968 2 Sheefs-Sheet 2 wem-0R ELMRR Ummm@ United States Patent O Int. Cl. F16b 15/,00;.F42b 31/00 U.S. Cl. 85-10 2 Claims ABSTRACT OF THE DISCLOSURE A securing device or anchoring element such as a nail, bolt, etc., which is adapted to be driven into a hard receiving material such as a concrete or a steel includes a shank portion with a pointed end which is enclosed by a casing of elastic material at least adjacent the pointed end of the shank portion. The construction includes a collar portion formed on the shank adjacent the pointed portion. A casing of elastic material surrounds the pointed end from the collar to the pointed tip and is preferably widened at the location at the tip to provide a shoulder to increase the driving power range at the target material into which the anchoring device is to be driven.

SUMMARY OF THE lINVENTION This invention relates, in general, to the construction of anchoring devices and, in particular, to a new and useful anchoring device of a type which is adapted to be driven into a hard receiving material by a power operated setting tool and which includes a collar formed at a location adjacent the pointed end thereof and with a casing of an elastic material surrounding the pointed end up from the tip to the collar.

The present invention is particularly applicable for applications of securing elements to a hard brittle material such as concrete. When bolts of this nature are to be driven into the concrete, the concrete is stressed by shear and it is thus loosened or cracks in the proximity of the drive in point. The result is that it chips during further use thereof. The loosening of the target concrete material as well as the subsequent chipping thereof leads to a reduction of the holding power of the bolt in the concrete. In addition, the chipping causes the surface of the concrete to become marred. Attempts to prevent this by applying a collar to the rear part of the bolt shaft or shank portion have not lead to satisfactory results, since the chipping cannot be prevented in this manner. The collar does tend to strengthen the concrete material which becomes loosened by the driving operation.

In accordance with the present invention, there is provided an anchoring device which includes a shank portion which is covered with a casing at least at the forward tip portion and up to a collar which is formed on the shank portion or on a driving barrel of a setting tool. The surrounding casing provides means for exerting force in the driving direction on the surface region of the concrete surrounding the drive in point. The casing provides this protection surface even before the driving process starts so that cracking and loosening of the target material is avoided. In addition, the concrete will not tend to chip away after the anchoring device is driven in.

An anchoring device such as a bolt is advantageously provided with a collar on the shank portion directly adjacent the pointed tip portion and the tip portion is surrounded by a casing of an elastic material which advantageously has an exterior diameter which increases toward the point. The casing provides means for insuring that the driving power which acts from the setting ICC tool driving piston to a collar portion of the setting element is transmitted by a surrounding casing at the tip portion to the target material in a wide area surrounding the drive in point. Shearing stresses are thus reduced from the outset and the loosening of the concrete and its subsequent chipping are avoided. The casing must comprise an elastic deformable material so that it is deformed but not destroyed by the driving in operation.

Securing devices are known which carry plastic caps on the pointed parts but as tests have shown, such devices do not prevent the occurrence of shearing stresses in a receiving material such as concrete, since they are not in an operative connection with the bolt which transmits the driving power. The pressure transmitted to the cap from the point of the bolt at the start of the driving process with such devices is completely insuicient. In addition, anchoring devices which include a casing surrounding the entire shaft of the bolt provides a good guidance and sealing of the bolt in the barrel of the driving gun and also insures the straight attachment of the bolt to the target material. However, the casing extends from the point to a collar provided between the head and the shaft portion but such a bolt cannot be used in the sense of the invention because the material forming the casing can be easily destroyed. Thus, the casing does not provide a sufficient transmission of power. In addition, the casings of these known elements are usually uniform in diameter and they do not provide a relatively large bearing surface surrounding the point at which the anchoring device is to be driven into the receiving material.

The securing device of the invention may thus include a collar which is formed by a transition from the shank portion to the head of the element but it is also possible to provide a collar as an extension of the shaft portion at a location directly adjacent the pointed end. This provides an additional advantage in that the driving piston of a setting tool can act on the collar arranged at the lower portion of the bolt provided the driving piston of the setting tool is provided with a deep bore to accommodate the remaining shank portion and the head of the securing element. This arrangement makes it possible to drive in very long bolts by applying the driving force to the collar arranged at the pointed end. The lcollar can also be formed by a part of the setting tool itself, for example, by a hammer piston =which embraces the head portion of the bolt by the provision of a receiving bore in the drive piston, but the forward end extends forwardly along the exterior `of the bolt t-o dene a collar which bears against the casing of elastic material.

It is particularly advantageous to provide a casing which widens from the location of the collar to the tip of the anchoring drive. In addition, it is desirable that the casing be narrower than the barrel of the setting tool so that a space remains into which the casing can yield in its deformation by the driving power. The casing is also provided with a wider shoulder directly adjacent the point which bears on the target material. In this way, a larger region around the drive in point is provided which prevents the loosening of the concrete and the chipping action caused by the driving in power. The casing advantageously comprises a plastic material and it functions not only in the manner set forth above, but also in preventing buckling and shearing of the bolt.

Accordingly, it is an object of the present invention to provide an improved anchoring element construction and arrangement including a collar formation on the anchoring element at a spaced location from the pointed tip and a casing of elastic material surrounding the anchoring element and advantageously being widened at the forward end to provide a large bearing surface against the material to which the anchoring device is to be inserted.

A further object of the invention is to provide an anchoring element which includes a collar formation thereon at a spaced location from the tip and which may be formed as a transition between the head of the element and the shank portion or as a widened collar forma* tion closed to the tip than the head portion, and including a surrounding casing extending from the tip up to the collar.

A further object of the invention is to provide an anchoring device which is simple in design, rugged in construction and economical to manufacture.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specicati-on. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a sectional view of an anchoring element having a surrounding casing constructed in accordance with the invention;

FIG. 2 is a view similar to FIG. 1 of another embodiment of the invention;

FIG. 3 is a View similar to FIG. 1 of still another embodiment of the invention;

FIG. 4 is a transverse sectional view through a setting device and anchoring element constructed in accordance with another embodiment of the invention; and

FIG. 5 is a transverse sectional view through a receiving material with a securing element therein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, in particular, the invention embodied therein in FIG. 1 comprises a threaded bolt anchoring element generally designated having a head portion 12 which is extremely threaded at 12a. The anchoring element 10 also includes a shaft portion 13 and a point 14.

In accordance with the invention, the head portion 12 is made to a larger diameter than the shaft portion and the transmission between the shaft portion 13 and the head portion forms a collar 1'6. A casing 15 of an elastic material such as a palstic extends from the collar 16 to the point 14. The outside diameter of the casing increases from the collar to the point 14 in order to provide a wide bearing surface at the target material and to facilitate the deformation of the casing.

In the embodiment of FIG. 2, a collar 26 is arranged 0n a shaft portion 23 of a bolt or securing element generally designated 20. The head portion 22 is provided with an external head 22a and it is made to the same diameter as the shaft portion 23. The collar is located close to the pointed end 24 and the pointed Vend 24 is surrounded by a casing 25 of elastic material which extends from the point up to the collar 26.

In the embodiment of FIG. 3, there is indicated a set- -bolt anchoring element generally designated which does not have any exterior thread on a head portion 32. The shaft portion 36 terminates in a point 34. The head portion 32 has a larger diameter than the shaft portion 33 and forms a collar 36 with the shaft portion. An exterior casing 35 of an elastic deformable material extends from the collar 36 to the point 34. The casing 35 has a widened shoulder 35a so that the driving power will be transmitted to a wide range around the drive in point.

In FIG. 4, there is indicated a bolt securing element generally designated 40 having a head portion 42 carrying an external thread 42a and a shaft portion 43 terminating in a point 44. The shaft portion 43 is surrounded by a casing 45 of an elastic deformable material which extends from a point up to a collar which, in this instance, is formed by the lower tip or annular portion 46a of a driving piston 46 of a setting tool having an exterior barrel 47. The setting tool 46 also includes a bore 46b into which the head portion 42 of the securing element 40' extends. The surrounding casing 45 is tapered from the location of the collar formed by the surrounding portion 46a of the drive piston 46 to the end adjacent the point 45 at a location overlying the receiving material or concrete 41. The casing 45 thus is provided with a shoulder portion 45a which rests on the target material 41. The casing 45 contacts the barrel 47 at the transition of the widened outer portion 47a and thus provides a means for guiding the bolt 40 during the Setting operation.

In FIG. 5, there is shown a bolt generally designated 50 of the type indicated in FIG. 4 by the configuration shown in FIG. 5 by the same driving process. In the set condition indicated in FIG. 5, the casing 55 can be screwed off the threaded end 52a of the head portion 52 of the anchoring device 50. During the driving in process, the casing 55 also protects the bolt shaft 53 and the point 54, since it counteracts any shearing forces which would act on the bolt shaft. An advantageous plastic for the casing of each of the embodiments is a polyethylene.

What is claimed is:

1. An anchoring element comprising an elongated shank portion, a head portion adjacent one end of said shank portion, said shank portion terminating at its opposite end in a pointed tip, and a collar of increased dimension formed at a spaced location from said pointed tip, a casing surrounding said shaft portion between said pointed tip and said collar and being of an elastic deformable material, said head portion and said shaft portion being substantially the same diameter, said collar comprising an exterior driving piston surrounding said head portion and extending to said shaft portion, said easing extending from the surounding drive piston to the pointed tip end and including a widened shoulder portion adjacent the pointed tip end adapted to rest on a target and a tapered portion from said widened shoulder portion tapered outwardly in a direction from said head portion to said tip, and a driving tool barrel including a rst portion surrounding said driving piston and a second widened portion surrounding said shoulder portion of said easing.

2. An anchoring device, according to claim 1, wherein said tapered portion of said casing contacts said barrel iirst portion at the junction of said first and second portions.

References Cited UNITED STATES PATENTS 2,724,116 11/1955 Termet. 3,377,903 4/1968 Korte.

FOREIGN PATENTS 529,320 12/1954 Belgium. 945,290 7 1956 Germany. 851,403 10/1960 Great Britain.

RAMON S. BRITTS, Primary Examiner U.S. Cl. X.R.