Electrical receptacle mounting spacers

When an electrical device such as a receptacle switch or the like is fixedly wired into building wiring, it is electrically and mechanically connected to an outlet box inside the wall. The device is fastened to the face of the box by screws. Ordinarily, the opening in the wall for recessing the device has minimal clearance to admit only the device and the device has extending projections that engage the wall surface around the opening so that the device mounts flush with the wall surface. When the opening is oversize, the projections pass through the opening and the workman cannot secure the receptacle firmly and mount it flush with the wall. The invention provides a set of insulated horizontal spacer members mounted parallel to one another and flexibly joined together by flimsy vertical joining elements that are readily broken apart. The workman can break off a portion of the assembly that will provide the necessary total spacing thickness and place it between the projections and the junction box. The horizontal members have an axial hole for receiving the screw that fastens the device to the box. The members are molded of a suitable insulating plastic with enough resilience so that the joining elements holding individual members apart collapse when the screw is tightened.

BACKGROUND OF THE INVENTION 
This invention relates generally to junction boxes and electrical 
accessories thereto and more particularly to means for mounting 
conventional switches, outlets and the like on electrical junction boxes 
so that they are flush with the wall surface and securely held in place. 
Electrical wiring inside building walls generally runs through conduits to 
junction boxes. Wall mounted electrical devices such as switches, outlets 
and the like are electrically connected to the wiring within the junction 
box and the device is mounted flush with the wall by grounding screws that 
pass through a metal yoke on the device and into threaded tabs on the 
junction box cover. A hole in the finish wall is made just large enough to 
admit the device. The yoke has extended ears that engage the outer wall 
surface around the hole as the grounding screws are drawn up so that the 
device assumes a predictable flush orientation relative to the surface and 
is held firmly thereto. A cover plate is then secured to the device for a 
finished appearance covering the mounting elements. 
Occasionally the hole in the wall is too large and the ears cannot engage 
the outer wall surface. The device cannot be securely mounted in flush 
position without awkward measures. 
Moll in U.S. Pat. Nos. 3,720,783 issued 3/13/73 and 3,651,245 issued 
3/21/72 describes metallic tubular spacers that can be broken off at lines 
of weakness to provide adjustable spacing with a rigid metal to metal 
connection between yoke and junction box for secure mounting and secondary 
electrical grounding. Pliers can be used to snap off the unwanted portion 
of the tube, but two pliers should be used to ensure snapping off at the 
desired level. Since the tube is rigid and there is a finite distance 
between lines of weakening, the final length of spacer may not position 
the device exactly flush with the wall. Moll further provides a cover for 
the junction box with a fire retardant collar that extends out past the 
wall. This collar has break away portions that may be broken or cut away 
with pliers to be flush with the wall. This is an awkward and expensive 
assembly that increases labor costs without providing the completely flush 
arrangement desired. 
SUMMARY OF THE INVENTION 
It is accordingly an object of the invention to provide a supplemental 
means for securely mounting an electrical device on a junction box so that 
the device will be flush with the wall surface when the workman finds that 
the ears on the yoke cannot make contact with the wall in the usual 
manner. It is a further object that the means be easy to use and 
inexpensive. 
The spacer means of the invention comprises a plurality of flat, thin 
members arranged in a stack, having a common hole to receive the grounding 
screw passing axially through the stack. The individual members of the 
stack are joined together by flimsy joining elements that are easily 
pulled apart at a level selected to yield a stack of suitable length for 
the particular spacing requirement. The shortened stack is placed between 
yoke and mounting tabs on the junction box cover and the mounting and 
grounding screw is passed through the combination and screwed in. As the 
screw is tightened, the joining elements bend and the gap between 
individual members disappears. The entire assembly is molded in one piece 
from a resilient plastic. As the screw is pulled up snug, the individual 
members can be compressed slightly so that the level of the yoke at that 
point can be adjusted to the level of the wall. The stack is quite long so 
that one stack may be used for a number of applications, the workman only 
breaking off as much as is needed.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
Referring now first to FIGS. 2,3 and 4, the invention comprises a stack 1 
of thin, flat horizontal members 2 joined together by flimsy vertical 
connecting elements 3 and 4. The stack 1 is topped by a convenience loop 5 
that can hang the device from a workman's belt or a merchandise display. A 
common screw-receiving hole 6 runs axially through all the horizontal 
members 2 as indicated by center line 7. The connecting elements 3 and 4 
are shown to scale in FIGS. 2 and 3, but are exaggerated for illustrative 
purposes in FIG. 4. They are arranged in staggered orientation so that the 
device may be molded of plastic in one piece by a simple opening and 
closing mold. The mold does have the complexity that a rod or mandrel to 
form the hole 6 must be moved in and out with each molding operation. 
The embodiment shown in FIGS. 5,6 and 7 overcomes this problem by providing 
alternate rectangular members 10 and 11 having long and short sides with 
side opening holes 7 and 9 that open at alternate long sides. The flimsy 
vertical connecting elements 12 and 13 may have lines of weakening 14. The 
mold for this embodiment is less costly. 
FIG. 1 shows how the device of the invention is used. A junction box 15 
with junction box cover 16 has two mounting tabs 19 and 20 with threaded 
screw holes 21 to receive grounding screws 25 that hold metal yoke 24 of 
electrical device 22 in place. Ordinarily, the hole 21 in the wall 17 is 
cut just large enough to receive the electrical device 22 (a wall 
receptacle) but small enough so that the ears 23 on yoke 24 of device 22 
engage the face of wall 17. This is the case for the lower ears 23. 
Mounting screw 25 is then passed through hole 26 of the yoke and lined up 
with and engaged in threaded hole 27. When the screw 25 is pulled up 
tight, the yoke is held against the wall surface in position to receive a 
cover plate that will rest against the wall and cover the assembly. The 
upper portion of hole 21 in wall 17 has been inadvertently made too large 
so that yoke 24 would be drawn into the hole by the grounding screw. This 
often happens especially with a gypsum plaster wall where a piece of 
plaster may break off incorrectly. Since it is awkward to interrupt 
electrician's work to call in a plasterer to correct the problem, it may 
be ignored. This results in a loose device and a poor electrical ground. 
Or makeshift shims may be prepared at considerable cost in skilled labor. 
The problem is quickly solved by the device of the invention. The 
electrician estimates the length of spacer required. He breaks off from 
the stack 1 an appropriate length to form a short stack 29. The flimsy 
vertical connector elements 3 and 4 are easily broken away at the desired 
level by pulling apart with the fingers. He positions this short stack 29 
between the tab 19 on the junction box cover and the yoke so that holes 6 
line up with the mounting holes and passes the mounting and grounding 
screw through the combination. As the screw is drawn up, the flimsy 
connecting elements 3 and 4 or 12 and 13 are bent away and deformed so 
that the flat faces of the horizontal members 2 are pressed together. The 
device is made of a resilient plastic that yields sufficiently under 
compression that the yoke may be pulled up exactly to the desired flush 
position for a very secure assembly without regard for breaking away a 
short stack of a precise length. The distance between members 2 may be 
arranged to equal the thickness of the members to simplify estimation of 
how much to break off, since it will be twice the distance. 
There are enough horizontal members in one stack to allow one stack to be 
used for many connections. 
The above disclosed invention has a number of particular features which 
should preferably be employed in combination although each is useful 
separately without departure from the scope of the invention. While I have 
shown and described the preferred embodiments of my invention, it will be 
understood that the invention may be embodied otherwise than as herein 
specifically illustrated or described, and that certain changes in the 
form and arrangement of parts and the specific manner of practicing the 
invention may be made within the underlying idea or principles of the 
invention within the scope of the appended claims.