US1718438A - Screw anchor - Google Patents

Description

June 25, 1929.v T w, Ross 1,718,438

SCREW ANCHOR Filed. Oct. 18, 1926 Patented June 25, 1929.

UNITED STATES THOMAS W. ROSS, OF UNIVRSITY CITY, MISSOURI.

SCREW ANCHOR.

Application filed October 18, 1926. Serial No. 142,280.

This invention relates to improvements in screw anchors, and consists in the novel construction hereinafter disclosed.

An object of the invention is to provide a screw anchor that may be readily inserted in the surface of walls or other building surfaces without damage to the structure of the surface in which it is inserted, the device constituting a socket for the reception of a screw whereby an object may be attached to the building surface in a permanent manner and Withoutdanger of the screw becoming displaced.

Other objects of the construction will be apparent from the following description taken in connection with the accompanying drawing, in which Fig. 1 represents a building surface with the screw anchor inserted therein.

Fig. 2 is a vertical section through the building surface showing the anchor disposed therein.

Fig. 3 is a view similar to Fig. 1 showing the screw in association with the anchor.

4 is a` perspective view of a preferred 'form of the anchor structure.

Fig. 5 illustrates a modified form of screw anchor set in a building surface.

F ig. 6 shows the same construction with the screw in place.

Fig. 7 is a perspective view of a modified form of the screw anchor.

F ig. 8 is a cross section vtaken either on the line 8 8 of Fig. 1, or on the line 8 8 of Fig'. 9 is a cross section taken on the line 9 9 of Fig. 5.

In the drawing a building wall, ceiling, floor or other part of a. building structure is indicated by 1. The material of which the element 1 may be composed may be cement, plaster, gypsum partition, or any other usual material from which building walls, ceilings or floors are constructed. It is known that such material does not constitute a satisfactory anchor for screws used in attaching telephone instruments, hangers, electric sockets or other devices required to beA applied direct to the building surface.

The anchor constituting the present invention is shown in perspective in its preferred form in Fig'. 4, and in its modified form in Fig. 7. A's shown in Fig. 4 the anchor comprises a polygonal body 2 preferably rectangular in cross sect-ion at the ends and having a series of notches 3 in each of its longitudinal edges. Running longii'indinally through the body 2 is a central opening 4 of a diameter slightly less than the diameter of the threads of the screw to be anchored therein. The body 2 is composed of any suitable material, preferably of such material as lead or other soft metal, although it will be understood that a hard fiber or similar material may be utilized if desired. Vhen originally formed the opening 4 is cylindrical and, as the screw enters the opening it cuts corresponding female threads to receive the threads of the screw. In the form shown in Fig. 7 one end of the body 2 is tapered as indicated at 5.

The manner in which the anchor is mounted to the building' wall or other portions of the building construction to which it is to be applied comprises boring a circular hole indicated at 6 by a drill or other tool to a suitable depth, so that when the anchor is inserted in the opening the outer face thereof will be flush with the face of the wallto which it is applied. After the opening' has been made it is Iilled with some quick hardening plastic material, such as plaster of Paris, cement plaster or the like, and the anchor is inserted while the filling for the hole is in plastic condition.

It will be understood that the diameter of the opening 6 is slightly in excess of the cross diameter of the body 2, so that the corners of the body 2 fit closely against the inner surface of the opening 6 and, as the body 2 is inserted in the plastic filling in the opening, the material constituting the filling will pack closely against the sides of the body 2 and fill the notches 3. Upon hardening the plastic material holds the body 2 rigidly in place, prevent-ing it from moving out of the supporting material or from turning within the opening.

In the form shown in Fig. 7, the tapered inner end of the body 2 constitutes a Wedge, increasing to a slight degree the facility with which the body may be inserted in the plas tic filling. After the anchor has set in the plastic material, the screws may be inserted by threading them into the opening 4.

It will be noted that the anchors may be readily centered at proper positions in relation to the building' structure by marking centers for the openings 6, which centers are the points at which the screws are to enter the anchors. It is obvious that the anchors may be readily set and that after having CII been positioned the plastic material is hardened and a very permanent support for the' screws is provided. It is also obvious that the appearance of the anchors in the building Walls will be unobjectionable, because the plastic material before linally setting can be smoothed around the anchor and may be made to conform to the face of the building Wall.

It is to be understood that the invention may be varied Within equivalent limits Without departing from the spirit and scope thereof. I do not limit myself unessentially, but what I claim and desire to secure by Letters Patent is y l. A screw anchor comprising a solid soft metal polygonal body, said body having a series of transverse notches in its corners, anda hole centrally located in said body to receive a screw therein.

2. A screw anchor comprising ay solid polygonal body adapted to be set in plastic material and having transverse notches at its corners, the notches serving to anchor the body in the plastic material, and a hole extending longitudinally through the body,

said body being composed of material in which screw threads may be cut While said body remains integral and unsplit throughout its length.-

THOMASY `W. ROSS.

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