US3491933A

US3491933A - Anchoring element guide construction and driving device therefor

Info

Publication number: US3491933A
Application number: US615834A
Authority: US
Inventors: Elmar Thurner; Herbert Rangger
Original assignee: Hilti AG
Current assignee: Hilti AG
Priority date: 1967-02-13
Filing date: 1967-02-13
Publication date: 1970-01-27
Anticipated expiration: 1987-01-27

Description

Jan. 27, 1970 E THUiRNER 1 ET'AL ANCHORING ELEMENT GUIDE CONSTRUCTION AND DRIVING DEVICE THEREFOR Filed Feb. 13, 1967 FlGl INVENTORS F IG. 4

ELMAR mum/ER HERBERT RAAGGEA? wlggw7mm United States Patent US. Cl. 227-139 2 Claims ABSTRACT OF THE DISCLOSURE An anchoring element such as a nail or bolt is described in respect to a guide element of destructible plastic material therefore and also in respect to the configuration of the barrel portion of the driving gun or powder charge-driven piston device for driving the anchor element into a hard receiving material such as steel or concrete.

The invention concerns the construction of a guiding and aligning element for a bolt which comprises a tubular member of a destructible material such as plastic. The tubular member has a bore therethrough which is adapted to receive the driving end of the anchor element in its one end. The opposite end of the tubular member is centered against the material into which the anchor element is to be driven so that the anchor element may be aligned in the barrel of the powder charge-driven piston device. The invention is particularly applicable for use with a so-called barrel piston device in which the anchor element does not rest on the target or receiving material in the firing position of the device but is arranged inside the barrel of the firing device at a spaced location from the material. With such firing device the anchoring element together with its propelling piston member will be moved a certain distance before the anchoring element strikes into the target material. This produces a more favorable etfect than thrust piston devices in which the bolt tip is arranged to rest directly on the target material in the firing position.

In accordance with one embodiment of the sleeve element which provides for the mounting and alignment of the anchoring element within the barrel of the driving device, there is provided a sleeve element which is provided with a bore which tapers inwardly or narrows towards one end, which end is positioned directly on the target material. The opposite end is arranged within the barrel of the driving device and it is engaged with the forward tip of the anchor element so that it centers the element above the target but at a spaced location therefrom. The sleeve member is made of a material which will shatter when the anchoring element is driven downwardly and into the target material.

A modified form of the invention includes a sleeve element with a foot formation or base preferably in the form of a wheel like member having the spokes which extend radially inwardly from an outer rim and engage the guide sleeve. The foot advantageously includes knurled or frictional portions around its periphery which facilitate engagement within the barrel of the driving device.

In accordance with a further feature of the invention, the driving device is provided with a cylindrical recess for accommodating the movable driving piston together with the guide sleeve device and the mounting foot portion. The barrel is also provided with laterally extending recess portions defining a chamber for accumulating the shattered guide sleeve elements when the anchor element is driven into the foundation.

3,491,933 Patented Jan. 27, 1970 SUMMARY OF THE INVENTION This invention relates in general to anchoring devices and to driving means therefor and in particular to a new and useful guide construction for the anchoring elements which provides means for holding the anchoring element within a driving device so that it will be centered at a spaced location from the receiving material and to an improved construction of a driving device with a chamber formation for accumulating the pieces of the guide element which will shatter when the anchor element is driven into the receiving material.

The anchor elements usually comprise nails or bolts which are driven into a hard receiving material such as steel or concrete by means of a powder charge-driven piston device. Within the general class of piston devices there is a type which is referred to as a thrust piston device which includes means for firing an anchoringelement which is arranged within the barrel of the device so that its tip rests on the receiving material in the firing position. In addition, there are also the so-called barrel piston devices wherein the bolt tip is held away from the receiving or target material in the firing position of the device. The barrel piston devices include a piston which will move together with the anchoring element within the barrel of the device by a certain distance before the anchoring element contacts the receiving material into which it is eventually driven. Such devices have a more favorable effect in the firing thereof than the thrust piston devices particularly for short bolts for steel penetration, insofar as the recoil forces are concerned. This is due to the fact that the piston and the anchoring element may travel for a certain distance, the so-called free flight distance, before'the anchoring elements tip strikes the target material and before the tip must do the driving work. While this piston is being moved through this free flight distance, it leaves the explosion chamber of the cartridge which provides its driving force and releases the gas outlet openings which are provided for the expansion of the explosion gases so that these gases can no longer transmit the impact force of the anchor element hitting the target material back to the driving device. With the so-called thrust piston devices on the other hand, there is the risk that the gas outlet openings will not be released completely by the piston which moves only a very short distance during the entire driving process so that the recoil would be relatively great.

The disadvantage of the piston barrel devices is that the bolt must be inserted in a laborious manner by means of a rammer and the bolt must be held in a firing position within the barrel of the driving device. Another disadvantage is that the known thrust piston devices include safety devices which can be overcome by resting the tip of the securing element to be driven into the material on the target material and by exerting a force through the element to overcome the spring pressure acting on it. This cannot be done with barrel-type devices because the bolt tip cannot offer a back pressure to such a safety spring.

In accordance with the invention, there is provided a guide element for the anchoring element or bolt which provides an extension of the bolt to accurately orient the bolt in a position at a spaced location from the target material. The guide element is preferably tubular or sleeve-shaped with a bore opening on each end. The securing element is engaged into the bore at one end and the opposite end of the sleeve is positioned over the target material. By using a sleeve to guide and position the anchoring element within the barrel of the driving device, the advantage of reduced recoil which is obtained by pirston barrel devices may be obtained in a powder charge driven piston device and even with very small securing elements and without having to put up with the disadvantages of a thrust piston device.

Accordingly, it is an object of the invention to provide a guiding sleeve device for use in association with an anchoring member such as bolt and which includes a through bore which is open at one end for receipt of the bolt and which is adapted to be aligned over the target material at its opposite end.

A further object of the invention is to provide a guiding and aligning device for positioning a securing element such as a bolt into the barrel of a driving device which includes a tubular member having a foot portion of a diameter substantially equal to the diameter of the barrel of the device and which includes means for frictionally holding the foot member in position in the barrel and wherein the sleeve member is provided with an opening at its upper end for receiving the tip of the anchoring device in frictional engagement therein, the guiding device being made of a material which will break upon firing of the driving device and wherein the driving device is advantageously made with a side chamber for accommodating the broken pieces of material.

A further object of the invention is to provide a guiding device for positioning an anchoring element Within a barrel of a thrust piston driving member and an improved construction of the barrel of the driving member which are 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 specification. 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 partial elevational and partial sectional view of a positioning and guiding device for an anchoring bolt constructed in accordance with the invention;

FIG. 2 is a perspective view of another embodiment of positioning and guiding device assembled with an anchoring bolt;

FIG. 3 is a transverse sectional view through a barrel of adriving device for use with breakable guiding devices; and

FIG. 4 is a bottom plan view of the driving device, along line 44 of FIG. 3.

DETAILED DESCRIPTION Referring to the drawings in particular, the invention as embodied therein in FIG. 1 comprises a positioning and guiding sleeve generally designated 2 which is of substantially cylindrical donfiguration and includes a bore 3 which is tapered inwardly from an opened anchoring element receiving end 2a to a target positioning end 2b.

In accordance with the invention, an anchoring element 1 such as a bolt is provided with a pointed end which is adapted to penetrate the hard foundation and a threaded end 1b which provides means for securing another element thereto. The guiding and positioning device or guide sleeve 2 is advantageously secured with the bolt .1 and they are oriented together within a chamber of the firing device with the end to be positioned on the target material so that the bolt 1 will travel through the bore 3 to cause breaking of the guiding and positioning device 2 as it is propelled into the material into which I portion 20 which is mounted on a foot or base portion generally designated 4. The base portion 4 is provided with spoke elements 4b which are connected at their inner ends to the cylinder 20 and at their outer ends to a surrounding rim or annular piece 4a. The rim 4a is advantageously provided with knurled or frictional portions 4c for aiding in the frictional engagement of the rim against the interior wall 11 of a barrel part or stand plate 10 of a thrust piston type driving tool generally designated 30.

Thus, the guiding and positioning device 2 provides a mounting and positioning means for an anchoring element for bolt 1 which includes a lower end 1a which is pointed and which includes a knurling or roughening 22 to reduce the tendency of the bolt shaft to take along plastic particles of the sleeve 20 and thus lessen its holding force in the target material. By knurling the forward end of the bolt, the depressions of the knurling will accumulate the plastic particles at a location which will not cause a sliding effect on the part of the bolt shaft which will engage the target material.

The embodiment of FIGS. 2-4 provides a foot-shaped widening or base 4 which insures accurate positioning of the sleeve or cylinder 20 centrally within the bore 1.1 in which the thrust piston 24 is movable. The guiding effect provided by the positioning and guiding device 2' insures that even with a slight slant of the sleeve portion 20 during the driving process that the bolt tip will always be forced into a path which extends substantially along the axis of the barrel and this is particularly important when the device is used to drive the anchoring device 1' into concrete 26.

It was found that a favorable way of aligning and guiding the bolt 1' is to provide a plastic positioning and guiding element 2 with a base portion 4 which is shaped in the manner of a spoke wheel. A feature of the construction of the driving device 30 is that it is provided with laterally extending chambers 13 on each side of the piston cylinder 11 to provide a receiving chamber for the parts of the positioning and guiding device 2' which are destroyed during the driving process. The chambers 13 are formed so that they do not interfere to any great degree with the cylindrical configuration of the barrel and the guiding of the piston 24 and the anchoring element or bolt 1 during the driving process.

The inventive guiding and positioning

devices

2 and 2 thus provide means for accurately positioning a securing element within the barrel of the driving device 30 at a location in which the tip of the securing element Will be spaced from the target material so that the securing element Will travel a free flight distance before impact. This free flight distance depends on the length of the sleeve but the desired barrel piston effect will be achieved in any case. The construction permits easy insertion of the positioning and guiding device together with the securing element or bolt Without requiring any special tool such as a hammer. Because the positioning and guiding device 2' With the foot 4 centers the anchoring element 1', it will be accurately positioned with its threaded end 1b into a chamber 24a of the piston.

A further advantage of the inventive construction is that the positioning and guiding device 2' may be used with a driving device 30 which has a safety device which is actuated by absorbing the pressure of a spring on the anchoring element 1 which is compressed in the firing position of the driving device. With the invention, despite the fact that the anchoring element 1' does not rest directly on the target material, it is still possible to move the driving device 30 out of safety since the sleeve will rest on the material and can transmit the contact pressure to the anchoring element 1' and the piston 24.

The inner bores of the positioning and guiding devices 2 and 2' are advantageously made with a conical tapering inwardly in the driving direction to insure a continuous exact axial guidance of the bolt 1 during its movement through the sleeve and during its penetration into the target material. The devices 2 and 2' advantageously consist of a hard plastic with a relatively high modulus of elasticity such as an acetal resin, for example, particularly suitable is a plastic which is known under the tradename of Delrin which in addition to its great hardness and high modulus of elasticity is anti-adhesive and has a coefficient of friction which has a favorable influence on the lubricating eifect of the plastic which must be kept low. The lubricating effect must be low in order that the bolt does not take along too many particles of plastic when it is driven into the target material which would reduce the extraction values of the bolt. A reduction of the lubricating effect by entrained plastic particles is achieved according to another feature of the invention in that the bolt is provided along the part of its shaft with a knurling in Whose depressions the plastic particles can accumulate without causing a sliding effect on the surface of the bolt shaft. Polyethylene and nylon have proved by investigation to be less suitable to the construction of a positioning and guiding device because they impart an excessive lubricating effect. Polystyrene is not too desirable because it has excessive fragility. Principally, however, it is also possible to replace the above-mentioned plastic by a brittle light metal alloy ore, for example, aluminas which is cemented on the bolt.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. A combination anchoring element and guide member comprising an anchoring element having a pointed end which is adapted to be driven into a hard material, and a positioning and guide member of tubular configuration having a bore therethrough and having an inner end which is opened and engaged over the pointed end of said anchoring element, said positioning guiding member having an outer end with an opening for the opposite end of the bore, said outer end being adapted to be positioned on the material into which the anchoring element is to be driven, said positioning and guiding member being made of a plastic material and having a cylindrical portion surrounding said tubular portion adjacent its outer end and having a rim of substantially larger diameter than said tubular portion with a plurality of spokes connected between said rim and said tubular portion, said anchoring element pointed end having knurling thereon for entraining particles of said plastic positioning and guiding member when it is driven into a target and being at a location thereon which will not reduce its holding force.

2. In combination, a piston driving tool and an anchoring element with guide means comprising a driving tool having a substantially cylindrical barrel with an end with an opening which is adapted to be positioned over the material to receive the anchoring element, a positioning and guiding member comprising a tube having a bore therethrough with one end of said tube being positioned on the material through which the anchoring device is to be inserted, an anchoring element having a. pointed end extending into the bore of said positioning and guiding device from the inner end and having an opposite portion extending upwardly within said barrel, and a thrust piston slidable in said barrel engageable with the anchoring element and being movable along said barrel for moving said anchoring element through the positioning and guiding member to break it as said anchoring element is driven into a target material, said barrel having a laterally extending chamber for receiving the broken particles of said positioning and guide sleeve which which is located adjacent the opening which is adapted to be positioned over the receiving material, said guiding and positioning member including a foot portion surrounding its outer end of a dimension substantially the same as the interior of the barrel of said driving tool and which is of a wheel-shaped configuration and includes an outer rim and a plurality of radial spokes, said outer rim having frictional means thereon for frictionally engaging the interior of the barrel of said driving device.

References Cited 2,855,817 10/1958 Kopf -10 3,377,903 4/1968 Korte 8510 3,382,751 5/1968 Kopf 22710 X THERON E. CONDON, Primary Examiner R. L. SPR'UILL, Assistant Examiner U.S. Cl. X.R.