US2756945A

US2756945A - Tension reel for lighting fixtures

Info

Publication number: US2756945A
Application number: US501621A
Authority: US
Inventors: Robboy Nathan
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-04-15
Filing date: 1955-04-15
Publication date: 1956-07-31
Anticipated expiration: 1973-07-31

Description

N. ROBBOY July 31, 1956 TENSION REEL FOR LIGHTING FIXTURES Filed April 15, 1955 v 1 6 mm M m m V T N A MM m l, A NM United States Patent TENSION REEL FOR LIGHTING FIXTURES Nathan Robboy, Cleveland Heights, Ohio Application April 15, 1955, Serial No. 501,621

2 Claims. (Cl. 242-107) This invention relates to supports for lighting fixtures and particularly to a tension reel support.

Fixture supports affording vertical adjustment for lighting fixtures commonly use a reeled cable housed in an egg or ball shaped case which is suspended. from the ceiling between the fixture and the ceiling canopy. Such cases are unsightly and detract from the appearance of the fixture installation. Furthermore, such devices ordinarily use a pawl type positioning mechanism in holding the suspended fixture in position, such as employed in window shades. Unless carefully released, the reeling action of the operating spring or weight will jerk the fixture upward out of the users hand with resultant jarring or damaging of the fixture and light bulb. In addition, the pawl action of the locking mechanism means that the fixture can be located only at intervals governed by the shape and size of the pawl and the spacing of its cooperating lock notches.

The primary object of this invention, therefore, is to provide a tension reel for lighting fixtures whose controlling mechanism is housed within the ceiling canopy usually used with such fixture, entirely concealed therein and unseen by the observer.

Another object is to provide a tension reel for lighting fixtures which permits the suspended fixture to be moved smoothly up or down at the touch of a finger while holding the fixture at any desired position instantly upon release.

A further object is to provide a tension reel of the type stated that is an improvement over the Tension Reel For Lighting Fixtures invented by me and described in my copending application Serial No. 474,709 filed in the United States Patent Office on December 13, 1954.

Still other objects are to provide a tension reel that is economical to manufacture, simple to install, rugged and reliable in action and adapted to support fixtures of different weights.

These and other objects of the invention will become apparent from a reading of the following specifications and claims, together with the accompanying drawing, wherein:

Figure l is a front elevation of the tension reel that is the subject of this invention, showing it mounted in a ceiling canopy and supporting an electric fixture therefrom in alternate raised and'lowered positions;

Figure 2 is a front elevation of the tension reel in its unmounted condition;

Figure 3 is a side elevation of the same with portions broken away and in section; and

Figure 4 is an exploded view of the housing and drum assembly.

Referring more particularly to Figure 1, there is seen the tension reel assembly broadly indicated by reference numeral 10, mounted within a conventional ceiling canopy 11 and having an electric fixture 12 suspended from the end of its supporting cable 41. Electric current is carried to the fixture 12 through a coiled cord 14 which 341 The member 13 is U-shape'd with two parallel top and

bottom walls

17 and 16 respectively joined through a first side wall 15, as is seen most clearly in Figure 4. The top wall 17 has two spaced mounting slots 20 by means of which the housing is attached to theelectric outlet box in the ceiling 44, through mounting. bolts not shown. Referencenumeral 21 indicates a slot in the edge of the top wall for a purpose to be hereinafter disclosed.

The first sidewall 15 has a hole 43 for passage of the electric cord 14 and a bearing hole 38 in which the shaft 27 is journaled. The bottom wall has a hole 19 for passage therethrough of the electric cord 14 and an opening 18 for passage of the supporting cable 41. The bottom wall also has a slot 22 cut in its edge for a purpose to be disclosed hereinafter. A cable tube 25 is seated in the opening 18. A dependent threaded canopy collar is positioned on the bottom wall over the two

holes

18 and 19 and around the tube 25.

Reference numeral 34 indicates a second side Wall having an end portion extending at a right angle thereto. A hearing hole 37 in the wall 34 acts as a journal for the shaft 27. The second side wall 34 also has

ears

35 and 36 positioned on its upper and lower edge respectively.

The second side Wallis mounted on the U-shaped housing member through the ears 35' and 36 which slidably engage the slots 21 and 22, respectively, of the top and

bottom walls

17 and 16. When so mounted, the side wall 34 is parallel to the first side wall 15 and movable toward or away from the wall 15 in the slots 21 and 22.

Reference numeral 27 indicates a drum shaft extended through and journaled in the

bearing holes

37 and 38 of the housing so assembled. The shaft 27 supports a cable drum 31 between the" first and

second side walls

15 and 34 over the tube 25 in the bottom wall opening 18, as shown in Figures 2 and 3. When so positioned, the diametric hole 28 in the shaft 20 is positioned beyond the outer face of the second side wall 34 and the threaded end 30 of the shaft is extended beyond the outer face of the first side wall 15, as shown in Figure 2.

Reference numeral 26 indicates a ribbon or flat spring which is nested within the drum 31 with one end anchored in a slot 29 in the shaft 27 and the other end attached to the drum 31. The drum 31 is freely rotatable upon the shaft 27. A cotter key 39 passesthrough the shaft bore 28 and is positioned against the outer face of the side Wall 34. A nut 40 engages the threaded end 30 of the shaft and bears against the outer face of the first side wall 15 when drawn up.

Reference numeral 41 indicates a flexible steel cable which is coiled around the face of the drum 31 and attached at one end to the drum. The cable passesthrough the tube 25 and has a fixture engaging element 42 attached to its free end from which the fixture 12 is suspended. The electric cord 14 is coiled around the cable tube 25 and connected to the electric fixture at its lower end. The upper end of the cord 14 passes through the bottom wall hole 19 and the side wall hole 43 into the electric outlet box in the ceiling when it is connected to the electric supply line. The canopy is slipped over the collar 23, hiding the reel 10 from view, and is locked in place by means of locking element 24 which engages the collar 23. as shown in Figure 1.

In adjusting the device originally, the cotter key is rotated thereby rotating the shaft 27 to load the spring to which the drum 31 is attached until the torque developed just balances the weight of the fixture 12. The key 39 is locked in place by passing its extreme end through the slot 21 and bending the end over so that the key can not rotate. The nut 40 is then drawn up upon the threaded end 30 of the shaft 27. This action draws the shaft through the first end wall bearing 38. Since the cotter key 39 on the other end of the shaft 27 bears against the outer face of the second side wall 34, the drawing up of the nut on the shaft 27 causes the second side wall to move in the slots 21 and 22 toward the first side wall 15. In so moving, the second side wall 34 compresses the drum 31 between it and the first side wall 15. As a result of this compressive action, the

edges

32 and 33 of the drum 31 are brought into frictional engagement with their

respective side walls

34 and 15.

It will be noted that the cotter key 39 can be locked only in a position giving a minimum adjustment of one revolution of the shaft 27. Exact balance is thus achieved by means of the adjusting nut 40 which draws the second side wall 34 against the edge 32 of the drum, as explained hereinabove. The braking force of the walls 34- and 15 against the drum edges is calculated to prevent rotation of the spring loaded drum 31 when the full weight of the fixture 12 is suspended from the end of the cable 41.

The additional spring torque created by pulling the fixture down is not suflicient to overcome the braking drag created by the

side walls

34 and 15. As a result, the fixture will remain stationary in any position to which it is lowered. However, if the fixture is lifted, as must be done to raise it, the fixture weight may be reduced by three or four pounds momentarily. This reduction of the pull on the cable 41 is sufiicient for the torque of the coiled spring 26 to overcome the drag of the

side walls

34 and 15 and the drum 31 is rotated easily, thus re-reeling the cable onto the drum 31. Release of the fixture restores the original load and the rotation of the drum stops, holding the fixture at the new point. At the same time, raising of the fixture causes the coiled cord 14 to contract to a taut new position. Thus both the cable 41 and the cord 14 are always neatly taut, there being no unsightly loops created as a result of raising the fixture.

It will be noted that no pawls or other mechanical ratchet means are employed in this device, so that the supported fixture can be moved smoothly to the exact position wanted where it will remain upon release without any minor upward or downward movement. Furthermore, it will be evident that the device just described is fabricated from simply shaped sheet metal elements that are inexpensive to form and easily assembled.

It will now be clear that there is provided a device which accomplishes the objectives heretofore set forth. While the invention has been disclosed in its preferred form, it is to be understood that the specific embodiment thereof as described and illustrated herein is not to be considered in a limited sense as there may be other forms or modifications of the invention which should also be construed to come within the scope of the appended claims.

I claim:

1. A tension reel for lighting fixtures, comprising in combination, a sheet metal housing having a U-shaped member defining top, bottom and first side walls, the bottom wall having an opening therein and a slot cut in the edge thereof, the top wall also having a slot cut in the edge thereof, a second side wall member having slot engaging ears at the top and bottom edges thereof engageable with the slots in the top and bottom walls, slidably mounted in said slots and movable therein toward or away from the first side wall, a spring loaded drum rotatably mounted between the first and second side walls over the bottom wall opening, a cable passing through said bottom wall opening, attached to the drum and coiled therearound, means on the free end of the cable for supporting a lighting fixture therefrom, means for moving the second side wall member in the U- shaped member slots toward the first side wall to compress the drum therebetween, and means for adjusting the distance between the second and first side walls so that their frictional bearing against the drum will hold the drum against rotation when a predetermined fixture weight is suspended from the cable but will be incapable of holding the spring loaded drum against rotation when a greater or lesser weight is applied to the cable.

2. A tension reel for lighting fixtures, comprising in combination, a sheet metal housing having a U-shaped member defining top, bottom and first side Walls, the bottom wall having an opening therein and a slot cut in the edge thereof, the top wall also having a slot cut in the edge thereof, a second side wall member having slot engaging ears at the top and bottom edges thereof engageable with the slots in the top and bottom walls, slidably mounted in said slots and movable therein toward or away from the first side wall, a shaft extending between said side Walls and journaled therein, said shaft having a diametric bore positioned beyond the outer face of the second side wall, an axially extending slot, and a threaded end extending beyond the outer face of the first side wall, a drum mounted on the shaft having side edges faced toward and parallel to said side walls, a ribbon spring coiled around said shaft nested within said drum and anchored at one end in the shaft slot and to the drum at the other end, a cable attached to the face of the drum, coiled therearound and extending through said bottom wall opening, means on the free end of the cable for supporting a lighting fixture therefrom, a key mounted in the shaft bore, against the outer face of the second side wall member, operable to rotate the shaft and attached spring to load the drum against rotation by a predetermined fixture weight suspended from the cable, lock means for holding said shaft spring at the required torque, an adjusting nut mounted on the threaded end of the shaft and rotatable against the outer face of the first side Wall to draw the shaft key against the second side wall to move the second side wall inwardly of the top and bottom wall slots toward the first side wall, thereby causing the drum to be compressed at its side edges between the inner faces of the first and second side walls, the distance between the first and second side walls being adjusted so that their braking pressure against the drum will counterbalance the increased torque of the spring due to the rotation of the drum caused by the unreeling of the cable brought about by the application of a force greater than the predetermined one, thereby holding the drum against rotation in the new position at all times; the side wall braking pressure being less than that required to overcome the spring torque acting to rotate the drum when the applied force is less than the predetermined one.

References Cited in the file of this patent UNITED STATES PATENTS 492,808 Jenkins Mar. 7, 1893 1,374,459 Lichty Apr. 12, 1921 FOREIGN PATENTS 582,643 Germany Aug. 21, 1933