Safety Fence

Abstract

A safety fence includes a plurality of posts having brackets and telescopic rails which are coupled to and supported by the brackets. The end sections of the rails include holes which are engaged by latches on the brackets to hold the rails in place. Each post is coupled to an anchor which is secured to a form of the type used to contain poured concrete. Each anchor is secured to the form by a rotatable shaft extending through the form and having a head at one end and a cam on the other, the cam being engageable with a follower on the anchor. The head of the shaft includes a handle. If the handle is rotated in a predetermined direction when the cam and follower are engaged, the anchor and the head are caused to securely abut against the form, thereby securing the anchor. The anchor includes an enclosure which prevents contact between the cam and subsequently poured concrete. When the poured concrete has set it further secures the anchor, thereby permitting removal of the rotatable shaft and the form while leaving the anchor secure.

Description

The subject invention relates to fences and in particular to provisional fences of the type used at construction sites.

Generally, a building is constructed by laying a foundation, erecting a framework on the foundation, installing utility conduits and fixtures, and erecting the bulding's internal and external walls. The task of working on the framework of a building under construction is, generally, hazardous. Therefore, to minimize the hazard, as the framework is erected or soon thereafter, carpenters erect fences or rails around the edges of the framework to protect construction workers whose jobs require that they work near those areas. Normally, the fences erected are tailor made from wood and nails so as to enclose open areas which, due to the distinctiveness of most buildings, often differ in size from building to building. In order to keep the cost of such fences down, wherever possible, carpenters utilize large pieces of lumber from fences which are no longer needed to put up the new safety fences. Nevertheless, the cost of the lumber and labor required to put up and take apart the fences constitute a necessary but very undesirable construction cost.

It is an object of the present invention to reduce the cost of provisional safety fences of the type used at construction sites.

It is another object of the present invention to provide sturdy fences which can be assembled from standardized and interchangeable parts.

It is still another object of the present invention to provide safety fences having reusable parts.

To achieve some of the objectives mentioned above, and others, the invention provides a safety fence for use in buildings under construction wherein forms are provided into which concrete is poured, the fence comprising: at least two rotatable shafts, each rotatable shaft extending through one of the forms and having a head at one end and a cam at the other; at least two anchors, each anchor having follower means which are engageable with one of the cams, whereby rotation of a cam engaged with the follower means causes the head of the shaft and the engaged anchor to securely abut against one of the forms to fasten the anchor; at least two posts, each of the posts being coupled to one of the anchors; and at least one rail supported by two of the posts, thereby providing a fence.

Additional objects and features of the present invention will become apparent by reference to the following description in conjunction with the accompanying drawings, in which:

FIG. 1 is a fragmentary elevational view of a safety fence according to the invention;

FIG. 2 is an exploded perspective view of part of the fence;

FIG. 3 is a transverse cross-sectional view of the fence;

FIG. 4 is a fragmentary view of a shaft having a cam at one of its ends;

FIG. 5 is a fragmentary horizontal cross-sectional view of the fence, showing a rail latched to a bracket, and a rail in the process of being latched to the bracket;

FIG. 6 is a perspective view of a rail having elbow shaped end sections; and

FIG. 7 is a fragmentary top view of a fence enclosing a hollow shaft, the fence having a right angle provided by rails having elbow shaped end sections.

A safety fence chosen to illustrate the present invention is shown in FIG. 1. In general, the fence 10 includes a plurality of posts 11 having brackets 12, each of the posts 11 being secured to one of a plurality of anchors 13; and a plurality of telescopic rails 14, each of the rails 14 being latched to and supported by two of the brackets 12. Referring to FIGS. 2 and 3, each anchor 13 includes pair of followers 17 and 18 and is coupled, in this example, to a form 15 of the type used at construction sites to contain poured concrete. The anchor 13 is coupled to the form 15 by a rotatable shaft 19, more fully described below, having a head 20 at one end and a cam 21 (see also FIG. 4) at the other, the cam 21 being engageable with the followers 17 and 18 of the anchor 13. In the coupling arrangement, the shaft 19 extends through a hole 22 in the form 15, the head of the shaft 19 abuts against the form 15, and the cam 21 engages the followers 17 and 18 of the anchor 13. When the shaft 19 is rotated to the position shown in FIG. 3, the cam and follower engagement cause the head 20 of the shaft 21 and a side of the anchor 13 to abut against the form 15, thereby securing the anchor 13 in place.

More specifically, as shown in FIGS. 2, 3 and 4, the cam 21 includes two semi-circular shaft extensions 23 and 24 located at one end of and about the axis of the shaft 19, each of the extensions 23 and 24 having a helical surface facing the other end of the shaft, i.e., its head 20. The helical surfaces 25 and 26 have the same pitch and begin from diametrically opposed positions. Each of the helical surfaces 25 and 26 is engageable with one of the followers 17 and 18, the followers being diametrically opposed (see FIG. 2). As a result, when the followers 17 and 18 are engaged by the helical surfaces 25 and 26 of the cam, rotation of the shaft 19 provides relative motion along the axis of the shaft between the shaft 19 and the anchor 13. To help overcome the frictional forces between the cam 21 and followers 17 and 18, and to cause the head 20 of the shaft and the anchor 13 to exert a pressure against the form 15, the head 20 includes a radially extending handle 27 which provides a mechanical advantage for rotating the shaft 19.

Referring to FIGS. 2 and 3, the anchor 13 is an angle member having two rectangular plates 29 and 30 joined at right angles. Fixed to plate 29 are two connectors 31 and 32, each of the connectors comprising a rod 33 perpendicularly extending from the plate 29 and a head 34 at the free end of the rod 33. The plate 30 includes a substantially circular hole 35 into which parts of the plate 30 extend to define the followers 17 and 18. As a result, the hole 35 resembles the letter H, the vertical portions of the letter being semi-circular. A cylindrical enclosure 36 extending from the inside of the plate 30 surrounds the hole 35 and serves, as more fully described below, to protect the cam 21 from poured concrete and the like. Further, the anchor 13 includes a rib 37 which is connected to the plate 29, the cylindrical enclosure 36, and plate 30. The rib 37 serves to reinforce the anchor 13 and includes an oblong hole 38 through which poured concrete can flow. As a result, when poured concrete sets within the hole 38, the anchor 13 is secured to the resulting concrete slab. After concrete 39 has been poured and it has set (see FIG. 3), the cam 21 which was protected from the poured concrete by the cylindrical enclosure 36, can be disengaged from the followers 17 and 18 and the forms 15 can be removed while the anchor 13 remains secured to the concrete.

It should be noted that the anchors 13 are secure and are capable of supporting a fence post 11 from the moment they are fastened to the forms 15 and after the forms 15 have been removed for use elsewhere, since by that time the anchors are firmly embedded in the hardened concrete. Thus, fence 10 may be used continuously to protect construction workers.

Referring to FIGS. 1-3 and 5, each fence post 11 includes a cylindrical tube 41, a base plate 42 fixed to one end of the cylindrical tube 41, and three spaced apart brackets 12 fixed to the cylindrical tube (see FIG. 1). The base plate 42 is perpendicular to the axis of the cylindrical tube 41 and includes two holes 43 and 44 (see FIG. 2) for engaging the anchor connectors 31 and 32. Each of the holes 43 and 44 includes a circular section which is slightly larger in diameter than the head 34 of the connectors 31 and 32, and an extension which is slightly wider than the diameter of the shaft 33 of connectors 31 and 32. The holes 43 and 44 are disposed on the base plate 42 so as to enable both of the circular sections to be slipped over the connector heads 34 on the anchor 13 and so that the radial hole extensions will be engageable with the shafts 33 of the connectors 31 and 32 if the base plate 42 is moved with respect to the plate 29 in the direction indicated by the arrow 45 in FIG. 2. When the radial extensions of the holes 43 and 44 engage the shafts 33, the heads 34 of the connectors 31 and 32 abut against the upper face of the base plate 42, thereby securing the post 11 to the anchor 13.

As shown in FIGS. 2 and 5, the brackets 12 may, for example, be manufactured from members of C-shaped cross-sectional contour. To securely support each of the rails 14 in the fence 10, each bracket 12 includes two similar latches 47 and 48. Latch 47 is associated with a rectangular hole 49 in the bracket, and includes a saw tooth shaped piece of resilient strip material 51, and a screw 53 which fixes one end of the strip material 51 to the bracket 12. The strip material 51 extends into the hole 49 an amount determined by the abutment of the free end of the strip 51 against the side of the bracket 12. Latch 48 is associated with a rectangular hole 50 in the bracket, and includes a saw tooth shaped piece of resilient strip material 52, and a screw 54 which fixes one end of the strip material 52 to the bracket. The strip material 52 extends into the hole 50 a predetermined amount which is determined by the abutment of the free end of the strip 52 against the side of the bracket 12. The latches 47 and 48 are symmetrically located about tube 41, the fixed ends of the resilient strips of material 51 and 52 being closest to the ends of the bracket 12. Each of the rails 14 includes two end sections 55 of C-shaped cross-sectional contour, which are slightly smaller than and slidably engageable within the brackets 12. Further, each of the end sections 55 includes a rectangular hole 56. Therefore, when the end section 55 of a rail is moved within a bracket 12 as is shown by the arrow 57 in FIG. 5, the end section 55 abuts against the strip material 51 of latch 47 and pushes it out through the hole 49 in the bracket 12. Further motion of the end section 55 causes the hole 56 in the end section 55 to coincide with the hole 49 in the bracket and the resilient strip material 51 snaps into the holes 49 and 56. Such an engagement is illustrated with respect to latch 48 in FIG. 5. As a result, the resilient strip 51 does not allow removal of the end section 55 from the bracket 12 unless, as more fully described below, someone deliberately withdraws the resilient strip 51 from the holes 49 and 56.

The end sections of the rails 14 may either be straight, as shown in FIGS. 1-3, or may be elbow shaped as is shown in FIGS. 6 and 7, the elbow end sections 65 being useable to provide non-linear fences such as, for example, the fence 66 shown in FIG. 7. Each elbow section 65 has a hole 56' for cooperation with latches 47 and 48. The end sections 55 or 65 of each rail 14 are slidably and telescopically coupled to a central section 58. The central section 58 includes two pairs of slots 60 and 61 in its horizontal walls (only one slot from each pair being shown in FIG. 6), the slots of each pair 60 and 61 being parallel to each other. As shown in FIGS. 2, 3, and 6, a pair of pins 63 and 64, each pin passing through a pair of slots in the main section 58 and a pair of holes in an end section serve to slidably couple each end section 55 or 65 to a main section 58. In consequence, the resulting telescopic rails 14 are useable with variably spaced posts 11.

To put up a fence 10 with the component parts described above, the anchors 13 are secured to forms 15 with the rotatable shafts 19 each carrying cam 21 and head 20, the base plates 42 of the posts 11 are engaged with the connectors 31 and 32 of the anchors 13, and the end sections 55 or 65 of the telescopic rails 14 are inserted into brackets 12 on the posts 11. The latches 47 and 48 on the brackets capture the ends of the rails and prevent accidental closure of the telescopic rails (see FIG. 1). If concrete is poured, the rotatable shaft 19 can be removed at any time after the concrete has set and secured the anchor. Enclosure 36 prevents the concrete from engaging cam 21. As shown in the drawings, the anchors 13, posts 11, brackets 12, rails 14, etc. are all standardized with respect to size so as to provide interchangeable fence parts. As a result, the fence parts can be quickly and securely coupled to each other.

When the need for fences 10 has expired, the latches 47 and 48 may be deliberately opened by engaging the free end of the strip material associated with each latch 47 and 48 and withdrawing the strip material out of its corresponding hole in the rail; the telescopic rails 14 can be removed; and the posts 11 can be decoupled from the connectors 31 and 32 on the anchors 13. Thereafter, the parts from the dismantled fence can be used elsewhere. Thus, all the parts described above can be reused, except for anchors 13 which remain embedded in the concrete 39.

Although the cams have been described as carried by shaft 19, the faces 25 and 26 could be perpendicular to the plane containing the axis of shaft 19, and the cam surfaces provided as the inner surfaces of followers 17 and 18.

It is to be understood that the description herein of a preferred embodiment according to the invention is set forth as an example thereof and is not to be construed or interpreted as a limitation on the claims which follow and define the invention.

Claims

What is Claimed is:

1. A safety fence for use in buildings under construction wherein forms are provided into which concrete is poured, said fence comprising:

a. shaft means adapted to extend through a form, said shaft means having an enlargement at each end,

b. anchor means for placement against one surface of the form, said anchor means having a follower engageable with one of the enlargements upon rotation of said shaft means to cause the anchor means and other enlargement to sandwich the form between them,

c. post means,

d. means for separably securing said post means to said anchors means,

e. railing means, and

f. means for separably securing said railing means to said post means.

2. A safety fence as defined in claim 1 wherein the head of shaft means includes a handle, said handle serving to provide a mechanical advantage for rotating the shaft means.

3. A safety fence as defined in claim 1 wherein the anchor means includes a plate having a hole and wherein the follower means include at least one extension of said plate into the hole.

4. A safety fence as defined in claim 3 wherein said anchor means includes an enclosure and said hole provides an entrance into the enclosure, whereby when said one enlargement and follower are engaged the enclosure prevents contact between the enlargement and poured concrete.

5. A safety fence as defined in claim 1 wherein the anchor means includes at least one connector for securing said post means.

6. A safety fence as defined in claim 1 wherein the post means includes a base for coupling the post means to the anchor means and a bracket for supporting the rail means.

7. A safety fence as defined in claim 6 wherein the bracket includes at least one latch and wherein the rail means supported by the bracket includes a hole engageable with at least one of the latches to secure the rail means to the post means.

8. A safety fence as defined in claim 1 wherein the rail means the rails is telescopic.

9. A safety fence as defined in claim 8 wherein the telescopic rail means includes at least one end section which is elbow shaped.

10. A safety fence as defined in claim 1 wherein one of the cooperating surfaces of said one enlargement and said follower is a cam surface for urging said anchor means and the other enlargement toward each other as said shaft means is rotated, to tightly squeeze the form between them.

11. A safety fence as defined in claim 10 wherein said cam surface is carried by said one enlargement.