US 3169007 A
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Feb. 9, 1965 v W. B. DUFFY ETAL MOUNTING MEANS Filed May 14, 1963 2 Sheets-Sheet l INVENTORS WILLIAM & DUFFY BYRlCHARD A NARTMAW Feb. 9, 1965 w. B. DUFFY ETAL MOUNTING MEANS Filed May 14, 1963 2 Sheets-Sheet 2 I/IMLIIIIIIII l/nm/l INVENTORS WILLIAM B. DUFFY RICHARD A. HARTM/IN A H-or/my 3,169,007 MOUNTING MEANS William B. Dufiy, Berkeley Heights, and Richard A. Hartman, Madison, N..I., assignors to United-Carr Incorporated, a corporation of Delaware Filed May 14, 1963, Ser. No. 280,382 7 Claims. (Cl. 248-343) The present invention provides for the expeditious mounting of concealed lighting-fixture casings, and the invention will be disclosed and discussed in that connection. Embraced within the invention are the organization as a whole, a subassembly and a gripping dog.
Concealed lighting-fixture casings or cans are commonly telescoped upwardly through an opening in the ceiling. Ordinarily the mouth of the can is provided with an outwardly-extending annular flange which engages the under surface of the ceiling and limits the upward movement of the can. Incorporated in the ceiling structure, and embracing the opening through which the casing or can is telescoped, is a sheet-metal plaster ring. This ring may be circular or rectangular, depending upon whether the lighting-fixture casing is of circular or rectangular cross section. In accordance with what seems to be trade usage we will use the term plaster ring without regard to the material of the ceiling. In other words we will call the ring a plaster ring regardless of whether the ceiling be of wet or dry construction, and regardless of I whether or not the ceiling contains plaster.
Except for relatively expensive arrangements, the previously-used arrangements known to us have a plaster ring that is provided with screw holes to receive horizontally-disposed screws for holding the lighting-fixture casing in mounted position. After telescoping the casing into p osition in the ceiling, the installer reaches up through the mouth of the casing and inserts screws through openings in the casing wall and threads them into the screwholes in the plaster ring. This is a cumbersome operation. After the installer has telescoped the easing into the ceiling he has to adjust it to align the screw openings in the casing Wall with the screw holes in the plaster ring. Then, while holding the casing in adjusted position, he must insert the screws. With only two hands to work with, it is ditlicult for the installer to hold the casing in adjusted position, hold the screw and, in addition, manipulate the screw driver. Moreover, the installation time is often longer than might be supposed, particularly when one or more screws are dropped while attempting to get them started.
A prime object of the present invention is to overcome the foregoing difficulties in the installation of concealed lighting-fixture casings or cans.
Other objects of the present invention are to provide a concealed lighting-fixture-casing arrangement having some or all of the following advantages: (1) the casing can be facilely mounted through the opening in the ceiling, (2) no tools are required to effect the retention of the casing in mounted position, (3) the casing can be installed by simply pushing it into position, (4) no special manipulation is required to adequately secure the installed casing, (5) additional securing of the casing can be readily provided if desired, and (6) the mounted casing can be removed or dismounted in practical manner.
An additional object of the invention is to provide a subassembly of plaster-ring and locking-dogs which con- 3,169,0h7 Patented Feb. 9, 1965 tributes to the accomplishment of some or all of the foregoing objects.
A further object of the invention is to provide a spring locking-dog which contributes to the accomplishment of some or all of the foregoing objects.
Still further objects are to provide a mounting arrangement, a spring-locking-dog organization, and a spring locking-dog which are usable with analogous advantages for purposes other than the mounting of concealed lighting-fixture casings.
Other objects and advantages will be apparent from the detailed description hereinafter taken in connection with the drawings.
In both the description and the claims parts at times may be identified by specific names for clarity and convenience but such nomenclature is to be understood as having the broadest meaning consistent with the context and with the concept of our invention as distinguished from the pertinent prior art. The best modes in which we have contemplated carrying out our invention are illustrated in the accompanying drawing forming part of this specification. Except as otherwise indicated the description refers to the specific form or forms of the invention shown in the drawing; it does not necessarily refer to any other form in which the invention may be embodied. The claims, however, do embrace other forms in which the invention may be embodied.
FIGURE 1 is a largely diagrammatic view showing a concealed lighting-fixture casing or can of the present invention telescoped into a ceiling. The ceiling and plaster ring are shown in section and the lighting-fixture casing is shown in elevation.
FIGURE 2 is a fragmentary perspective view, on a larger scale, showing the gripping of the lighting-fixture casing of FIGURE 1 at one of the vertical slots thereof.
FIGURE 3 is a top plan view of the spring locking-dog per se, that is shown gripping the casing in FIGURE 2.
FIGURE 4 is an elevation of the spring locking-dog per se, looking from the right of FIGURE 3.
FIGURE 5 is an elevation of the spring locking-dog per se, looking from the bottom of FIGURE 3.
FIGURE 6 is an elevation of the spring locking-dog per se, looking from the left of FIGURE 5.
FIGURE 7 is a fragmentary perspective view, on a much enlarged scale, showing the nose portion of the spring locking-dog that is shown in FIGURES 2 through 6.
FIGURE 8 is a fragmentary view in vertical section, with some parts in elevation, illustrating a preliminary step that is sometimes resorted to in the dismounting of a lighting fixture casing secured with dogs of the present invention.
FIGURE 9 is a fragmentary diagrammatic view, partially in vertical section, showing a screw that may optionally be inserted into the spring dog to additionally secure the lighting-fixture casing if desired.
FIGURE 10 is a diagrammatic plan view, looking toward the top of the ceiling, showing an installation in which the lighting-fixture can is rectangular. The body of the rectangular can is shown in horizontal section.
In FIGURE 1 the ceiling It has a circular hole 11 that is embraced by a plaster ring which is designated as a whole by 12. The ring 12 has a vertical tubular portion 14 which lines the circular hole 11, and has a washerlike annular-flange portion 15 which is against the top surface of the ceiling 16*. The plaster ring 12 may be supported from the building structure in any suitable manner, and the ceiling 11 may be of any suitable material and be installed in any suitable manner. In one type of installation the plaster ring is screwed or bolted to horizontal straps or bars, often of strap iron or the like, which are secured to the bottoms of consecutive joists. With the plaster ring thus premounted, the ceiling is installed in relation to the plaster ring. Sometimes the ceiling has a plaster coating which is applied wet and troweled into position against the plaster ring.
The lighting-fixture can or casing is designated as a whole by 17 it is of formed sheet-metal, often aluminum. It has a hollow cylindrical body or wall 18 which may be necked in at 19 as it approaches the closed end 20 of the casing. The mouth of the casing is open and it is provided with an integral annular flange 21 which encircles the body or wall 18 and projects outwardly therefrom. Before the casing 17 is telescoped into the ceiling 10 an electrical cable 24 is brought downwardly through the hole 11 in the ceiling and suitably connected to the casing 17 and the lighting fixture thereof. Then the casing 17 is telescoped upwardly through the ceiling, bringing the casing to the position shown in FIGURE 1 with the flange 21 against the bottom surface of the ceiling.
The casing-wall 18 is provided with vertical slots 22 which are equally distributed about the circumference of the wall 18. For each slot 22 in the casing-wall 13 the plaster ring 12 has a spring locking-dog 25 which is aligned with and engages the slot 22 as shown in FIGURE 2. These spring locking-dogs 25 hold the casing 17 in mounted position in the ceiling, as will be explained.
The slots 22 have a vertical extent and a vertical position such as shown in FIGURE 1. For many installations three slots 22, spaced 120 degrees apart, are suitable; and three slots 22 is what FIGURE 1 shows. For some in stallations a larger or smaller number of slots 22 might be used.
- The character of the spring dog 25 will be understood from a consideration of FIGURES 2 through 7. The dog is formed of sheet metal and has legs 26 and 27 which are at an obtuse angle to each other. The free end 28 of the leg 26 is upturned and, near such free end, a spring latching-finger 29 is struck upwardly from the body of the leg 26. Near the juncture of the legs 26 and 27 the leg 26 is provided with two shoulders 30, one on each side of the leg as shown. The leg 26 is generally flat and is adapted to be attached to a suitable support such as the plaster ring 12.
A Each of the spring dogs 25 with which the plaster ring 12 is equipped is secured to the plaster ring as shown in FIGURE 2. Struck upwardly from the horizontal annular-fiange 15 of the plaster ring is a straplike sheet-metal bridge 16. The leg 26 of the dog 25 is telescoped under the bridge, with the leg 27 of the dog facing inwardly of the plaster ring as in FIGURE 2. In telescoping the leg 26 under the bridge 16, the dog is first canted so that the upturnedv end 23 of the leg 26 can be entered under the bridge 16 at the edge thereof which faces toward the inside of the plaster ring. Then the dog 25 is swung downwardly to bring the leg 26 in parallelism with the flange 15. As the leg 26 is forcibly telescoped beneath the bridge .16, the latching finger 2% is flexed downwardly by engagement with the bridge. As the telescoping movement is completed, the two shoulders 30 engage that edge of the bridge 16 which faces toward the inside of the plaster ring and the latching finger 29 snaps out into latching relationship with that edge of the bridge which faces toward the outside of the plaster ring.
With the spring dogs 25 attached to the plaster ring 12-, one dog for each slot 22, the legs 27 of the dogs extend. inwardly of the tubular portion 14 of the plaster ring and the tips of the noses of the dogs lie on a circle that is somewhat smaller than the circumference of the body or wall 18 of the lighting-fixture casing 17. The
noses 35 are V-shaped as will more fully appear. As the lighting-fixture casing is telescoped into the mounted position shown in FIGURES l and 2, the casing wall 18 cammingly engages the noses 35 of the spring dogs and forces them outwardly, thereby affording ready telescoping of the casing 17 to the mounted position shown in FI URES 1 and 2.
If the slots 22 are in alignment with the noses of the dogs 25 as the casing 17 is telescoped to mounted position, the V-shaped noses 35 of the dogs will enter the slots and engage the opposite edges thereof as shown in FIG- URE 2. As the casing 17 is approaching its terminal position shown in FTGURES 1 and 2 the installer checks, by rotative feel applied to casing 17 or otherwise, to ascertain whether the noses 35 of the spring dogs are in the slots 22. If they arent, the installer rotates the casing 17 about its vertical axis until the noses 35 of the dogs 25 snap into the slots 22. If-the circumferential spacing of the slots 22 is accurate, and if the corresponding circumferential spacing of the dogs 25 is accurate, perfect alignment of each dog 25 with a slot 22 will be achieved. However, our construction will accommodate a measure of inaccuracy in the circumferential spacing of the slots 22, the dogs 25, or both. The two shoulders 36 and the latching finger 29 of the dog 25 serve to maintain the holding relationship between the bridge 16 and the locking dog 25 even with considerable looseness or lost motion between the dog and the bridge. We provide such looseness or lost motion, whereby each dog 25 can shift a little and can also pivot somewhat on a vertical axis passing approximately through the center of bridge 16. This renders each of the dogs 25 individually self-adjusting, to a reasonable extent, to effect correct engagement of the V-shaped nose 35 of the dog with its companion slot 22 despite reasonable inaccuracy in the circumferential position of the dog or the slot or both.
The leg 27 of the dog 25 has two triangular side portions 34 which are bent backwardly and provide the leg 27 with the V-shaped nose 35 that enters and engages the slot 22 of the lighting-fixture can 17; see FIGURE 2. The ends 34a of the bent-back portions 34 are hooked toward the wall 18 of the lighting-fixture can 17, being bent along lines 34b. The metal is so sheared that the tips of these hooked ends 34a have the shearing burrs in engagement with the edges of the slot 22. Upon an attempt to move the mounted can 17 downwardly, the burred edges of the ends 34a bite into the edges of the slot 22. The plurality of fasteners 25 with which the plaster ring 15 is equipped co-operate to make togglelike gripping engagement with the casing 17, which gripping engagement increases as downward force applied to the mounted casing increases. To mount the casing 17 it is only necessary to telescope it to the position shown in FIGURE 1 with the slots 22 aligned with the dogs 25, whereupon the casing is firmly held in mounted position by the togglelike gripping action of the spring dogs 25.
The triangular bent-back portions 34 are, among other things, cams which are adapted to come into play if and when it is desired to dismount the casing 17. By forcible rotation of the casing 17 about its vertical axis, in either direct-ion, one of the triangular bent-back side portions 34 of each dog 25 is cammingly acted upon by an edge of the slot 22 with which the dog is engaged. The legs 27 of the dogs are flexed outwardly and, as the surface of the casing-body 18 moves sidewise with respect to the dogs 25, the smooth unslotted surface of the casing moves under the noses 35 of the dogs. Each nose 35 has a small fiat 38, shown in FIGURE 7, which slidably engages the unslotted surface of the casing-wall 18. The plane of the flat 38 is substantially vertical and is now substantially tangent to the surface of the casing-body 18, with the result that the holding grip of the spring dog on the casing has now been eliminated and the easing 17 can be pulled downwardly and dismounted.
As perhaps best seen in FIGURE 2 the leg 27 of the spring dog 25 has a longitudinally extending slot 40 which, at the midpoint of its length, is enlarged into a circular hole 41. The slot 40 is useful in carrying out a preliminary step that is sometimes resorted to in dismounting the casing. In a few installations the mounting casing, e.g. casing 17' in FIGURE 8, presents nothing that can be conveniently gripped to forcibly rotate it and cam the spring dogs out of engagement with the slots 22. In such case a screw-driver blade 44 may be inserted through the slot 22 as shown in FIGURE 7, the tip of the blade be engaged in the slot 40 of the spring dog 25, and then the screw driver be pushed to flex the leg 27 outwardly to the dotted-line position shown in FIGURE 8. It will be understood that the blade 44 of the screw driver is wedge-shaped in thickness and that the width of the slot 40 is such that only the tip of the blade passes through the slot. With the leg 27 disengaged from the casing wall 18, downward prying force can be exerted with the screw-driver blade to move the adjacent portion of the casing downwardly a little. By progressing from spring dog to spring dog in this manner with a screw driver, the casing can be walked downwardly sufficiently to enable the flanfe at the mouth of the casing to be gripped for forcible rotation of the casing and dismounting of the same as already explained.
The normal gripping action of the spring dogs 25 is such that they will sustain a relatively heavy load. Specifically we have found that with an aluminum casing 17 that is thick a downward force of as much as forty pounds per locking dog 25 can be safely imposed. With such high load-sustaining capacity per locking dog it is apparent that in some installations a single spring locking-dog would suffice if the installation provided a sheath or other suitable means to maintain the alignment of the mounted member.
With such high holding forces by the normal gripping action of the dogs 25, further support is rarely required. However, additional support can be provided by inserting a pan-headed sheet-metal screw 48 through one or more of the slots 22 as indicated in FIGURE 9. The arrow 48 is threaded into the round hole 41 of the spring dog 25. The head of the screw spans the slot 22 and the thread of the screw elfects some helical flexing of the margin of the hole 41 without need for flowing metal of the spring dog.
A lighting-fixture casing which is rectangular in cross section may be installed in like manner and be removed in analogous manner. Usually the wall of the casing will have four or more slots 22, divided between the opposite sides of the casing. The plaster ring will be rectangular in conformity with the rectangular form of the casing. In FIGURE there is shown schematically a rectangular lighting-fixture casing 17", having a vertical wall 18" and an outwardly-extending annular flange 21" at the mouth of the casing. One side of the casing wall 18" has two vertical slots 22 which are the same as the slots 22 in FIGURE 1. The opposite wall of the casing has two like vertical-slots 22. The rectangular plaster ring 12 has a washerlike flange 15" which is on top of the ceiling 10" and carries four of the spring locking-dog 25, one for each of the slots 22 in the easing. The V-shaped noses 35 of the spring locking-dogs engage in the slot 22', the same as in FIGURE 2. At least one-half inch of space is allowed at S and S between the wall 13" of the rectangular lighting-fixture casing and the confronting face of the plaster ring. This is so that the lighting-fixture casing 17 can be bodily shifted in a srtaight line to either the right or the left of the position shown in FIGURE 10 to cam the noses 35 of the locking dogs out of the slots 22 and bring them into sliding engagement with the wall 18 of the casing 17" for dismounting of the casing as already explained.
In the drawing the thickness of sheet metal is necessarily exaggerated. We have stamped the spring locking-dog 25 from annealed spring steel .020" thick, and hardened and tempered the dog after forming. Also, we have used the following approximate dimensions:
Over-all length of the spring dog as viewed in FIGURE 3 Q inches Length of leg 26 as viewed in FIGURE 3, taken from the free end of the leg to its juncture with leg 27 "inches" Width of the mid portion of leg 26 as viewed in FIGURE 3 inches Width of the widest part of leg 26, viz. at its junction with leg 27 inches Dimension of upturned end 28 lengthwise of leg 2e and as viewed in FIGURE 3 inches Perpendicular distance from lower face of leg 27 in FIGURE 5 to a parallel plane which passes through the two free corners of the bent-back triangular portions (34 including 34a), one of such free corners being seen in FIGURE 5, and both of such free corners being seen in FIGURES 3, 4, 6 and 7 inches Width of bridge 16 radially of plaster ring 15 inches Angle between legs 26 and 27, with the dog 25 unstressed, degrees Inclination of leg 27 to the wall 18 of the lightingfixture casing before the dog is stressed, degrees We claim:
1. A plaster ring to telescopically receive a lightingfixture casing; and a plurality of spring dogs distributed about the ring, each dog being of sheet metal and having two degs at an obtuse angle to each other, one leg being attached to the ring, and the other leg projecting into the path of a lighting-fixture casing telescoped into the ring, said other leg having a V-shaped nose to grippingly engage a vertical slot in the lighting-fixture casing.
2. A plaster ring to telescopically receive a lighting fixture casing; and a plurality of spring dogs distributed about the ring, each dog being a single piece of sheet metal and having two legs at an obtuse angle to each other, one leg being attached to the ring, the other leg projecting into the path of a lighting-fixture casing telescoped into the ring, said other leg having a V-shaped nose to grippingly engage a vertical slot in the lightingfixture casing, and the tip of the nose being flat for nongripping sliding movement of the casing thereover when the nose is in engagement with an unslotted portion of the casing.
3. A slotted member mounted by telescopic movement of the member in the direction of the length of the slot, and a spring dog having a V-shaped nose engaging the slot and strongly opposing reverse movement of the member, the nose including a cam surface operable upon sidewise relative movement of the mounted member and the dog to cam the nose of the dog out of the slot and release the member for dismounting.
4. A one-piece spring dog composed of sheet metal, the dog having a generally flat leg for attachment to a support and having a second leg for engaging and holding a member, the two legs being at an obtuse angle to each other and the second leg having side portions which are bent back and provide the second leg with a V-shaped nose for making holding engagement with a slot in said member.
5. A one-piece spring dog composed of sheet metal, the dog having a generally flat leg for attachment to a support and having a second leg for engaging and holding a member, the two legs being at an obtuse angle to each other and the second leg having side portions which are bent back and provide the second leg with a V-shaped nose for making holding engagement with a slot in said member, and the tip of the nose having a flat which is adapted to make sliding engagement with unslotted portions of said member.
6. A spring dog having a leg for attachment to a support, and having a second leg for engaging and holding a member, the second leg having a V-shaped nose for engaging a slot in said member and also having a hole for the reception of a screw to additionally hold said member. 7
7. A spring dog composed of a single piece of sheet metal, the dog having two legs at an obtuse angle to each other, the first leg being a support leg for attachment to a support, and the second leg being a grip leg for gripping and holding a member, the tip of the second leg being hooked toward the member for making the gripping engagement therewith, and the end portion of the second leg being V-shaped for engagement of the tip of the leg with a slot in said member.
References Cited by the Examiner UNITED STATES PATENTS 2,793,071 5/57 Meyer 4-187 2,885,691 5/59 Juergens 4-187 2,888,684 6/59 Icenhower 4-187 2,914,287 11/59 Henning 248-343 2,965,348 12/60 Gerstel et al 248-343 2,992,315 7/61 McDonnold 4-187 10 3,018,083 1/62 Bobrick 248-343 FOREIGN PATENTS 1,013,237 8/57 Germany.
CLAUDE A. LE ROY, Primary Examiner.
UNITED STATES PATENT OFFICE EERTlFlQA'lE 61F QQRREUHQN Patent No. 3,169,007 February 9, 1965 William B. Duffy et al It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below Column 5 line 24, for "flanfe" read flange lines 41 and 42 for "arrow read screw column 5, lines 57, 62 and 64 for "22 each occurrence, read 22 line 62, for "locking-dog" read locking-dogs line v69 for "srtaight" read straight column 6, line 33, for "degs" read legs Signed and sealed this 27th day of July 1965 (SEAL) Attest:
ERNEST W. SWIDER EDWARD J, BRENNER Attesting Officer Commissioner of Patents