Carpet Trim

Abstract

Carpet trim having flanges overlying the edges and flush with the carpet surface and supported so that when stepped on will yield or move down similarly as the carpet yields but without lateral movement (which otherwise could dislodge the edges or upset the pedestrian) and then return to flush position when the foot is removed. The support for the flanges provides for gradual lowering of the flush position as the carpet mats or wears.

Description

The invention relates to trim for protecting the cut edges of carpet installed on a floor. More specifically the invention relates to trim especially suitable for use in protecting the cut edges of carpet around an entrance device for an electrical underfloor distribution system.

Underfloor entrance means are often located in areas of relatively high pedestrian traffic density. It is important therefor that the entrance means be of a nature and character so as not to present a hazard to persons using the floor. This is a special problem where commercial carpet is used, because carpet over an entrance device must be removable in order for the interior of the device to be available from the floor. Thus the carpet around the device must be installed in a cut condition. The cut edges can unravel or become loose unless retained and protected from the foot traffic or wheels of vehicles.

The invention contemplates protecting the cut edges of the carpet with trim having a head flush on the surface and overlying the edges. The head when stepped on has roughly the same yielding characteristics as the carpet itself. This maintains the "feel" of the carpet and minimizes abrupt discontinuities and enhances maintaining of the normal walking conditions. When the load is removed the head returns to the normally flush position on the surface.

Ordinarily a contact with the head generates a compressive load which tends to push the engaged part of the head downwardly toward the floor. If the head is displaced laterally while moving downwardly this motion could upset the balance of the pedestrian. Furthermore, lateral motion could cause the edges of the carpet to be displaced from underneath the head. The invention contemplates a special structure for mounting the head whereby to minimize lateral motion to a degree such that the problems of unbalance and edge release are eliminated.

Areas high in pedestrian density are conducive to wear or matting of the carpet. If wear or matting of the carpet should cause the surface to assume a position substantially lower than the head, the same would then present a tripping hazzard. In addition, the head would appear as a ring raised above the carpet surface and this would be especially undesirable from an esthetic standpoint.

According to the invention the head in its yielding and then returning to flush position takes into account the wear and matting or flattening characteristics of the carpet. The structure and material provide that the head in effect has a "memory" which corresponds to the "memory" of the carpet. In this way the head always assumes a desired flush position on the carpet surface irrespective of matting or wear.

The principal object of the invention is to provide carpet trim of the kind in question which makes it truly practical to use carpet on a floor having an electrical underfloor distribution system.

Another object of the invention is to provide carpet trim of the kind in question which is adaptable without loss of advantage in a variety of forms each specifically suitable for installation on covers of under-floor junction boxes, access units, hand holes, trenches and the like.

Another object of the invention is to provide carpet trim having a head flush with the carpet surface and covering the cut edges, the head being supported so that when tramped or stepped on will yield similarly as the carpet itself yields and returns to flush position after the foot is removed.

Another object of the invention is to provide for carpet trim having a head, flush with the carpet surface and covering the cut edges, the head being supported so that when stepped on will yield similarly as the carpet yields and returns to flush position when the foot is removed and which will, over a period of time, return to a lower position compatible with the matting or wear of the carpet.

Another object of the invention is to provide carpet trim having a head, flush with the carpet surface and covering the cut edges, the head being supported so that when stepped on will move practically straight down without lateral motion whereby the head will remain over the cut edges and no gaps will appear which might otherwise dislodge the edges.

Another object of the invention is to provide for carpet trim having a head flush with the carpet surface and covering the cut edges, the head being supported so that when stepped on will move down without lateral motion and thereby retain the firm footing of the pedestrian.

The invention will be described below in connection with the following drawings wherein:

FIG. 1 is a plan view of the invention arranged in the form of a circular adaptor for use on underfloor access units or the like;

FIG. 2 is an enlarged view taken along lines 2--2 of FIG. 1;

FIG. 3 is an exploded view of the adaptor of FIGS. 1 and 2;

FIG. 4 is a sectional elevational view of the adaptor of FIG. 3 with the parts joined together;

FIG. 5 is a fragmentary view of a modified form of the adaptor of FIG. 4;

FIG. 6 is an enlarged fragmentary view of the wall structure of the adaptor of FIG. 4;

FIG. 7 is an exploded view of the invention arranged in the form of a rectangular adaptor for use on the cover of an underfloor junction box or the like;

FIG. 8 is a sectional plan view of one of the corners of the adaptor of FIG. 7;

FIG. 9 is a fragmentary perspective view of the invention arranged in strip-like form for use on covers of trench duct;

FIG. 10 is a fragmentary perspective view of the invention illustrating a modified form of wall; and

FIG. 11 is a fragmentary view of a modified adaptor.

In FIG. 1 the adaptor 1 has its base 2 secured to an access unit cover (not shown) by the screws 3. The carpet carried by the base of the adaptor is indicated at 4 and the carpet carried by the floor is indecated at 5. The adaptor has a head 6 which is flush with the surface of the carpet. The head extends over the edges of the carpet pieces 4 and 5 to retain and protect the same. Since the head 6 of the adaptor is exposed on the surface of the carpet it will be apparent that the head may be stepped on by the foot of a pedestrian or by some object such as a wheel of a cart.

A detailed view of the adaptor and its mounting on an access unit is set out in FIG. 2. The access unit 10 is buried in the concrete 11 and includes the hand-hole 12 which makes the interior of the unit accessible from the floor. The hand-hole 12 is covered by the entrance means including the outer ring 13, the adjusting ring 14 and cover 15. The ring 14 is mounted on the adjusting screws indicated at 16 which can move the cover vertically. The adjusting screws extend through the cover and provide for the cover to be adjusted flush with the floor. The cover 15 supports the adaptor 1. The screws 3 hold the base 2 of the adaptor form against the cover and also hold the cover firm on the adjusting ring.

The interior of the access unit is reached simply by peeling off the piece of carpet 4, removing the screws 3 and then lifting off the adaptor 1 and cover 15. Replacement is made in the reverse order.

Preferably the material for the invention is flexible plastic such as polyethylene. Moreover, since the contact between the foot and the head may be in a nature of a scuffing action it is preferred that the portion of the head contacted by the foot be formed of a scuff-resistant plastic. Also the head should be much stiffer than the wall yet capable of flexing or bending under a compressive load. ABS is a typical plastic suitable for the foregoing purposes.

The above in mind then the preferred form of the adaptor comprises two parts as best indicated in FIG. 3. An upper ring 20 is molded from scuff-resistant ABS plastic and a lower pan 21 molded from polyethylene. The pan 21 includes the base 4, the wall 22 and the shoulder 23. The shoulder 23 has several holes 24 to receive the studs 25 on the ring which lock the ring to the shoulder as by being heat-staked. Alternatively, the studs can be shouldered and snapped thru the holes so that the shoulder locks on the underside of the flange. With this construction no heat-staking is required.

While the two-part construction is preferred it will be understood that the ring and pan can be molded as a simple unit and an example of such a structure is shown in FIG. 5 where in the adaptor 1' comprises the head 6' and pan 21'. Integrally formed adaptors of the kind mentioned may be desirably used in applications where foot traffic is unlikely to result in repeated contact.

The ring 20 and the shoulder 23 form the head 6 so that there is an inside flange 26 covering the edge of the carpet piece 4 and an outside flange 27 covering the edge 8 of the carpet 5.

Preferably the parts are dimensioned so that the carpet must be tucked or forced under the flanges whereby the same exert a holding pressure which is amplified when the head is stepped on.

In the construction of the adaptor, the wall 22 is of special significance particularly from the standpoint of providing for the yielding and non-lateral motion of the head when the same is contacted.

As indicated, the wall is comprised of a plurality of serially spaced side-by-side legs 30 which are disposed around the periphery of the base 4 and extend upwardly therefrom.

The legs are connected to and extend between the base 4 and the shoulder 23. The foregoing structure is more clearly seen in the exploded view of FIG. 6. Each leg is generally rectangular in cross section. The material and shape of a leg determines its stiffness characteristics.

The use of a wall of the kind described, the connections to the shoulder and to the base together with the stiffness of the head are responsible for the non-lateral head motion.

We have found that the holding characteristics of the lower joint connection between the leg and the base can be determined by the radius along the vertical joints 31 and 32. Also the holding connection characteristics can be altered by a cut-out in the base between the legs as the cut-out indicated by the dotted lines 33. Similarly the holding characteristics of the upper joint of connection between a leg and the shoulder may be determined by the radius along the joints 34, 35 and 36. For the sake of clarity we have not shown any radii in the drawings.

The stiffness characteristic of a leg and the holding characteristics of the connections cooperate to provide that when the adaptor head is stepped on the middle of the leg moves out while the vertical alignment between top and bottom remains relatively unchanged. Thus there is little, if any, lateral motion. The leg folds, i.e., the middle of the leg moves laterally and the top half of the leg extends over the bottom half of the leg with the top and bottom in vertical alignment.

It will be understood, of course, that the stiffness of the head 6 provides for the same to move down and exert the compressive force on the legs or wall to cause the same to fold. Each leg will fold an amount as a function of the compressive force. Thus, for example, if only a small portion of the head is contacted the legs below the contact area will fold while the opposite legs remain relatively undisturbed.

With the type of action described the head moves down under compressive load with minimum of lateral motion.

The folding action as described above accounts for the yielding when the adaptor head is stepped on. As mentioned previously, the material and shape of a leg determines its stiffness or yielding characteristics. However, this may be modified by changing the radii mentioned above. Generally, the stiffness of the legs or the wall should be matched to the compressive characteristics of the carpet. The foregoing variables are used for matching.

When a compressive load on the head is removed it is important that the same move back essentially to the same position from which it came; i.e., flush with the surface of the carpet. The polyethylene plastic comprising the pan and the ABS plastic comprising the head both have the essential memory characteristics which are conducive to the return action. Thus, the stiffness of the wall and the head together with the connection of the wall to the shoulder and to the base provide for the head to return to unloaded position when the foot or load is removed.

With repeated folding the legs or wall will return to semi-folded condition. This results in a lower position of the head. The contacts which cause the wear and matting of the carpet also cause the semi-folding condition. Thus, as the carpet mats or wears the head also assumes a lower position down flush against the carpet surface.

The invention contemplates a rectangular shaped adaptor for use on junction boxes, etc. having the same features as the circular adaptor. Such an adaptor is illustrated in FIGS. 7 and 8.

The cover 40 is rectangular or square and is constructed to fit on a junction box, access unit, etc. and is adjustably mounted so that it can be made flush with the floor similarly as the cover shown in FIG. 2. The rectangular adaptor comprises the ring 41 and pan 42 both of which have the required rectangular shape in conformity to the particular cover with which the adaptor is used. The pan 42 includes the base 43, the wall 44 and shoulder 45. The shoulder 45 has several holes 46 to receive studs 47 which lock the ring to the pan as by being heat-staked. The wall 44 comprises a plurality of serially spaced side-by-side legs 48, the construction being similar to the legs shown for the circular adaptor.

The ring 41 and shoulder 45 comprise a head which has inside and outside flanges similar to the flanges 26 and 27.

With the rectangular type, it is essential that the wall at the respective corners have an open-type construction of the kind illustrated in FIG. 8 where it will be seen that the leg 48 a and 48 b are spaced from the corner 50. This structure is necessary to attain the non-lateral folding characteristics referred to above. The size of each corner opening is adjusted so that the corner has essentially the same stiffness characteristics as the wall.

Copending application Ser. No. 228,383 filed Feb. 24, 1972 entitled "CARPET AND TILE TRIM" and assigned to the assignee of this invention illustrates a composite tile trim and holder which is especially suitable for use on trenchducts. The trim of the invention is ideally suitable for use in holders of said application and examples of the same are illustrated in FIGS. 9 and 10.

In FIGS. 9 the trim piece includes the base 53, the wall 54 and the head 55. The base is constructed in accordance with the information in said application Ser. No. 228,383. The head includes the flanges 57 and 58 for overlying the cut edges of the carpet.

The material and shape of a leg determines its stiffness characteristics.

The characteristics of the connection between the leg and the base is determined by the radius in the side joint 60 and the face joints 61 and 62. Similarly the characteristics of the connection between the leg and the head is determined by the radii in the corresponding joints. Leg stiffness is modified by change of radii.

In FIG. 10 we have illustrated a modified wall. In FIG. 10 the trim piece includes the base 63, the head 64 and the wall 65. The base and head are similar to the corresponding parts in the trim of FIG. 9. The wall however, is comprised of solid plastic and includes an upper groove 66 on one side of the wall. The two grooves are co-extensive with the length of the wall. The material and shape of the grooves determine the stiffness of the wall.

The connection between the wall and the base is determined by the radius at the joints 70 and 71. And the connection characteristics between the top of the wall and the head are determined by the radii at the joints 72 and 73. The wall of FIG. 10 when subjected to a compressive load has a double fold; that is to say the upper part 66a of groove 66 folds over the lower 66b and similar action takes place in the groove 67.

While we have illustrated the trim of FIGS. 9 and 10 as being one piece it will be understood the invention contemplates a two piece construction similarly as described in connection with the circular and rectangular adaptors.

The invention contemplates using the cover to secure the adaptor to the entrance means. An adaptor structure 79 for this purpose is shown in FIG. 11.

The center of the adaptor is removed so that the base 80 is in the form of a ring. The base 80 is mounted on the adjusting ring 4 being sandwiched between the adjusting ring and the cover 15. The wall 81 of the adaptor extends up from the base between the edge of the cover and the ring and up above the surface of the cover. The wall carries the head 82. The wall 81 and the head 82 are constructed similarly as the wall and head in the adaptor in FIG. 2.

The arrangement of FIG. 11 is especially advantageous in large diameter entrance means for example, a diameter in the order of 22 inches. Not only is there a saving in plastic material but center buckling of the base is eliminated which might otherwise be the case in larger sizes if the adaptor were mounted directly on the top surface of the cover. It will be apparent that the base 80 serves as a gasket between the cover and adjusting ring and that the cover secures the adaptor in position on the entrance means.

The structure of FIG. 11 is also made in rectangular form with the corners being arranged as explained in connection with FIGS. 7 and 8.

Claims

We claim:

1. A carpet-underfloor adaptor for an underfloor entrance unit which has a circular shaped cover plate, the adaptor comprising:

a circular shaped head, a circular shaped wall and circular shaped base;

said base having means for engaging the top surface of a cover plate whereby to mount the adaptor on the plate;

said head being disposed above the peripheral edge of the base and including an outer flange and an inner flange, the outer flange extending outwardly in a direction away from the center of the base and being for use in extending over the edge of carpet installed on the floor for retaining and protecting the edge and the inner flange extending inwardly in a direction toward the center of the base and being for use in extending over the edge of carpet installed on the cover for retaining and protecting the edge and in such position the head being exposed on the surface of the carpet whereby to be susceptible to receive a compressive load such as being stepped on by a foot, the load being in a direction to move or bend the head toward the base and the head being made of resilient material permitting the head to move or bend toward the base when receiving said compressive load and to return to unloaded position with the compressive load removed;

said wall extending between the base and the head and around the peripheral edge of the base, the wall being formed with a plurality of side-by-side legs and being made of resilient material; and

lower joint means connecting the bottom of each leg of the wall to the base and upper joint means connecting the top of each leg of the wall to the head, the upper joint means providing for compressive load on the head to be transferred to legs of the wall and said upper and lower joint means respectively holding the top and bottom of each leg whereby said resilient material of a leg provides for the leg to fold when subjected to said compressive load and to return to unloaded position with said load removed and said fold being characterized by that the mid-section of a leg is moved laterally and the portion of the leg above the mid-section extends over the portion of the leg below the mid-section with the top and bottom of the leg in substantial vertical alignment whereby said movement of the head toward the base is accomplished with substantially no lateral motion.

2. A carpet-underfloor adaptor for an underfloor entrance unit which has a rectangular shaped cover plate, the adaptor comprising:

a rectangular shaped head, a rectangular shaped wall and a rectangular shaped base;

said base having means for engaging the top surface of a cover plate whereby to mount the adaptor on the plate;

said head being disposed above the peripheral edge of the base and having an outer flange and an inner flange, the outer flange extending outwardly in a direction away from the center of the base and being for use in extending over the edge of carpet installed on the floor for retaining and protecting the edge and the inner flange extending inwardly in a direction toward the center of the base and being for use in extending over an edge of carpet installed on the cover for retaining and protecting the edge and in such position a head being exposed on the surface of the carpet whereby to be susceptible to receive a compressive load such as being stepped on by a foot, the load being in a direction to move or bend the head toward the base and the head being formed of resilient material permitting the head to move or bend toward the base when receiving said compressive load and to return to unloaded position with the compressive load removed;

said wall extending between the base and the head and around the peripheral edge of the base, the wall being formed with a plurality of serially spaced side-by-side legs and in each corner of the wall there being a pair of adjacent legs which are spaced apart sufficiently so that there is an open space at the corner and the wall being made of resilient material; and

lower joint means connecting the bottom of each leg of the wall to the base and upper joint means connecting the top of each leg of the wall to the head, the upper joint means providing for compressive load on the head to be transferred to the legs of the wall and said upper and lower joint means respectively holding the top and bottom of each leg whereby said resilient material of a leg provides for the leg to fold when subjected to said compressive load and to return to unloaded position with said load removed and said fold being characterized by that the mid-section of a leg is moved laterally and the portion of the leg above the mid-section extends over the portion of the leg below the mid-section with the top and bottom of the leg in substantial vertical alignment whereby said movement of the head toward the base is accomplished with substantially no lateral motion.