Patent Application
20050101177
The present invention relates to electrical cord storage and handling apparatus, and more particularly to an electrical cord roll-up apparatus with axially arranged rings and brushes.
A loose electrical cord lying on the floor or on the ground can be a safety hazard, and can be damaged by people walking on the cord or vehicles driving over the cord. Electrical cord roll-up apparatus provide an easy means for storage of electrical cords. Such roll-up apparatus typically have a stationary assembly and a reel assembly rotably mounted on the stationary assembly. The reel assembly can be manually actuated, spring actuated or motor driven.
A plug or socket may be mounted directly onto the stationary assembly or a short “pig tail” cord may be connected to the stationary assembly. The primary electrical cord is electrically connected to the reel assembly which is in turn electrically connected to the stationary assembly, so that the primary electrical cord can be wrapped around the reel assembly without electrical disconnection. A high quality, consistent, wear resistant connection between the stationary assembly and the reel assembly is desirable.
Prior known devices have used radially spaced side contacts on either the stationary assembly or the reel assembly with radially spaced, disk shaped rings on the other assembly to make the electrical connection between the assemblies. The outwardly spaced contacts on such devices will wear more quickly. Rigidly mounted contacts on these devices can provide inconsistent electrical contact if there is end float or bearing looseness between the stationary and reel assemblies. U.S. Pat. No. 4,897,512 to Johnston and U.S. Pat. No. 6,331,121 to Raeford, Sr. disclose roll-up apparatus with substantially rigidly mounted, radially spaced side contacts.
Some prior known devices with radially spaced side contacts use thin, flat, metal contacts. Generally this type of contact projects at an angle between the stationary and reel assemblies. The resilience of the metal provides some pressure of the contact against the rings and limited compensation for relative movement between the stationary and reel assemblies. U.S. Pat. No. 3,929,210 to Cutler et al., U.S. Pat. No. 3,964,490 to Nelms, U.S. Pat. No. 4,300,665 to Arechaga, U.S. Pat. No. 5,701,981 to Marshall et al., and U.S. Pat. No. 6,349,808 to Bryant each disclose an electrical cord roll-up apparatus with thin, flat, metal, radially spaced side contacts.
U.S. Pat. No. 5,700,150 to Morin discloses an electrical cord roll-up apparatus with two axially spaced, thin, flat, metal contacts that project outwardly at an angle from the stationary assembly to contact cylindrical rings on the reel assembly. U.S. Pat. No. 6,273,225 to Park discloses an electrical cord roll-up apparatus having a complex shaft with axial spaced, electrically insulated contact portions. Opposed pairs of thin metal contacts are axially spaced and mounted on the reel assembly, with each contact wrapping partially around a contact portion. The consistency and quality of the electrical contact in the above two devices is limited by the contact pressure which is limited to the resilience of the contact metal.
An electrical cord roll-up apparatus includes a shaft assembly and a reel assembly rotably mounted on the shaft assembly. The shaft assembly has a hollow shaft, an insulator extending along a section of the shaft, axially spaced conductive rings on the insulator and a pigtail cord. The pigtail cord extends into the shaft and has a pigtail wire for each ring. The pigtail wires extend through the shaft and insulator, and one wire connects to each ring. The reel assembly has a reel tube with spaced side flanges at opposite ends, and a brush assembly mounted on the tube for each ring. The reel tube fits over the insulator and the brush assemblies are aligned with the rings and electrically separated or insulated from each other. Each brush assembly has an inwardly opening brush holder, a brush in the brush holder that electrically contacts a ring, and a compression spring that biases or presses the brush against the ring. The brushes are brass or copper. The brush assemblies include connectors that crimp onto the electrical cord and the electrical cord is rolled onto the reel assembly when the reel tube is rotated in one direction and unrolled when rotated in the opposite direction.
Details of this invention are described in connection with the accompanying drawings that bear similar reference numerals in which:
Referring to
The insulator 15 has a hollow, elongated cylindrical shape, and is sized and shaped to fit snugly over the cylindrical section 21 of the shaft 14 with the cylindrical section 21 of the shaft 14 extending axially beyond both ends of the insulator 15. The insulator 15 includes insulator wire apertures 27 that extend through the insulator 15 in alignment with the shaft wire apertures 24. The rings 16 are made of an electrically conductive material such as copper or brass and each have a hollow cylindrical shape. The rings 16 are mounted in an axially spaced relationship on the insulator 15 adjacent to the insulator wire apertures 27. Generally, three rings are provided, for grounded 120 volt three wire electrical cords. Other numbers of rings 16 may be used, such as four for four wire, three phase circuits.
The pigtail cord 17 shown extends into the interior cavity 19 of the shaft 14 from the open end of the threaded section 22 and includes a pigtail wire 29 for each ring 16. The pigtail wires 29 pass through the shaft wire aperture 24 and the insulator wire apertures 27, and are electrically connected to the rings 16. The pigtail cord 17 may end at an end of the shaft 14 or may extend any selected distance beyond shaft 14, and may be connected to a plug or socket, depending on the application.
The reel assembly 12 includes a reel tube 31, two bearings 32, first and second flanges 33 and 34, and a plurality of brush assemblies 35, with one brush assembly 35 for each ring 16 on the stationary assembly 11. The reel tube 31 has a hollow cylindrical shape with an inner diameter slightly larger than the outer diameter of the rings 16 so that the reel tube 31 fits over the rings 16 in a spaced relationship. The reel tube 31 is about as long as the cylindrical section 21 of the shaft 14 and extends beyond both ends of the insulator 15 when fitted over the rings 16. In the illustrated embodiment the reel tube 31 is made from a non-conductive or insulator material.
The bearings 32 fit into opposite ends of the reel tube 31 and rotably mount the reel assembly 12 on the stationary assembly 11. In the illustrated embodiment, the bearings 32 are pressed onto the cylindrical section 21 of the shaft 14 at opposite ends of the insulator 15. The first and second flanges 33 and 34 each have a generally flat, circular disk shape. The first flange 33 a center aperture 37 and a transversely extending circular wall 38 around the center aperture 37. The second flange 34 also includes a centered transversely extending circular wall 38. The circular walls 38 are sized to fit over the ends of the reel tube 31. The first and second flanges 33 and 34 are secured to opposite ends of the reel tube 31 and the reel tube 31 is secured to the bearings 32 by cap screws 36 through the circular walls 38 and through opposite ends of the reel tube 31, with the threaded section 22 of the shaft 14 extending through the center aperture 37 of the first flange 33. An axially outwardly projecting handle 39 is attached to the second flange 34 to facilitate manual winding of the reel assembly 12.
As shown in
The brush 41 slidably fits into the brush tube 47 and projects beyond the open end of the brush tube 46 to contact the ring 16. The compression spring 42 fits into the brush tube 46 between the tube cap 47 and the brush 41, to press or bias the brush 41 against the ring 16. The brush wire 43 is connected to the tube cap 47 and the brush 41, to electrically connect the brush 41 and the brush holder 40. The brush wire 43 is preferably made of flexible conductive material such as very small copper wires woven or braided together. The brush wire 43 provided has a selected length greater than the distance from the tube cap 46 to the brush 41, to accommodate wear in the brush 41 and looseness in the bearings 32, and to assure consistent pressure of the brush 41 against the ring 16. The brush 41 is preferably made of brass to minimize wear.
Referring again to
Although the present invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made by way of example and that changes in details of structure may be made without departing from the spirit thereof.
