Patent Application
20210095523
The present invention generally relates to the chain hoisting assemblies and, specifically to auxiliary chain assemblies for rolling doors and the like.
Protection and safety devices are important components of numerous mechanical machines and systems, particularly when heavy objects are being lifted. Rolling doors fall into this category as they can be extremely heavy and when there is a mechanical or electrical failure a rolling door can fall precipitously causing potential injury and damage to property. Numerous hoists are described, for example, in the following patents: U.S. Pat. Nos. 1,862,331; 1,937,331; 1,973,844; 2,044,565; 2,150,419; 2,269,438; 4,520,998; 5,127,631; 5,351,906 and 8,511,434. However, the hoist mechanisms are primarily designed to lift heavy objects and provide various levels of protection when failure occurs or when a user inadvertently or accidently releases a chain, cable or the like used to raise the object. Many of the designs described in the above enumerated patents are complicated and can be costly and not particularly suited for use with rolling doors.
Accordingly, it is an object of the invention to provide an auxiliary chain assembly that overcomes disadvantages in prior art hoist and chain assemblies.
It is another object of the invention to provide an auxiliary chain assembly that is simple in construction and economical to manufacture.
It is still another object of the invention to provide an auxiliary chain assembly that is well suited and can easily be incorporated for use with rolling doors.
It is yet another object of the invention to provide a rolling door with auxiliary chain assembly that enables the rolling door to be lifted manually while provides protection for controlled lowering of the rolling door when there is inadvertent release of the chain.
It is a further object of the invention to provide an auxiliary chain assembly that is easy to operate.
It is still a further object of the invention to provide an auxiliary chain assembly that provides automatic, quick and reliable braking when there is a failure that enables the rolling door to drop precipitately under its own weight.
It is still a further object of the invention to provide an auxiliary chain assembly as above suggested that enables simple and efficient raising as well as lowering of a rolling door.
In order to achieve the above as well as other objects a chain assembly comprises a shaft; a wheel secured to said shaft; a hand-operated means for rotating said wheel and said shaft about an axis; a one way bearing having an inner race secured to said shaft for rotation therewith and having an outer race that can freely rotate in one direction in relation to said inner race and prevented from freely rotating in another or opposite direction in relation to said inner race; a brake drum coupled to said outer race; brake shoe means arranged to be in operative contact with said brake drum to apply frictional forces to said brake drum when there is relative motion between said brake shoe means and said brake drum; brake adjusting means for adjusting the braking forces applied by said brake shoe means on said brake drum, said one way bearing being arranged to maintain said brake drum stationary in one direction of rotation of said shaft and to rotate said brake drum in the opposite direction of rotation of said shaft resulting in a degree of braking of said shaft as determined by said brake adjusting means.
Those skilled in the art will appreciate the improvements and advantages that derive from the present invention upon reading the following detailed description, claims, and drawings, in which:
Referring now specifically to the figures, in which the identical or similar parts have been designated by the same reference numerals throughout, and first referring to
The rolling door assembly 10 includes a rolling door or curtain 12 formed of horizontal slats 14 linked to each other in any conventional manner as shown. The slats 14 and, therefore, the curtain 12, are generally formed of steel and can represent a significant weight. The curtain 12 can be rolled up about a main horizontal shaft 16 between a fully raised condition to provide access to an entry point in a structure and a fully lowered position to close such opening or entry point. The edges of the slats 14 are received and generally slide within vertical tracks or rails 18 in any conventional manner. The curtain 12 is typically raised and lowered by an operator that includes a reversible motor drive for rotating the shaft 16 in either direction about its axis. The operator and motor drive therein are not shown in
An auxiliary chain assembly 24 in accordance with the invention is coupled with a gear 22 mounted on the main shaft 16, the gear 16 being coupled to the auxiliary chain assembly as to be more fully described.
The auxiliary chain assembly 24 is coupled to the gear 22 by means of a chain 26, the gears being selected to generally provide a desired gearing ratio, as well understood to those skilled in the art.
Referring to
An important feature of the invention is the provision of a stop brake assembly 48 secured to the side plate portion 28c in any conventional manner. The brake assembly 48 is also mounted on the hexagonal shaft 32, for reasons to be described. The hexagonal shaft 32 extends through the stop brake assembly 48 and is coupled to a chain gear 50, also mounted on the hexagonal shaft 32 for rotation therewith. The chain gear 50 is coupled to the chain 26 shown in
Referring to
Positioned within the brake drum 62 are two brake shoes 72, 74 pivotally mounted to apply more or less friction against the internal surface of the brake drum 62, as will be more fully discussed.
Referring primarily to
A tension spring 100 applies a force on the brake shoes 72, 74 to keep them in a retracted condition to reduce the friction applied by the brake shoes to the brake drum 62.
An optional feature is the provision of a fly lock out pin governor 110 provided with a smooth bore or hole 110a at one end and a spring retainer 110b at the other end. A rectangular protrusion projects outwardly between the two ends as shown. A bolt 112 extends through the hole 110a secured to a nut 114 to form a pivot about which the governor 110 can rotate. A lock washer 116 and a bushing 118 made from, for example, from bronze ensure that the governor 110 can rotate freely in response to centrifugal forces applied thereto upon excessive rotation of the retainer cover plate 60. A speed stop retainer tension spring 120 is applied between the spring retainer 110b and fixed pin or rivet 122 secured to the retainer plate 60. It will be clear that when the retaining cover plate 60 rotates above a predetermined speed the governor or fly lockout pin 110 rotates in a counter clockwise direction, as viewed in
Referring to
Referring to
With the one way bearing 68 the outer race is fixed or secured to the bearing retainer ring 64 while the inner race is locked to the hexagonal shaft 32. The outer race rotates with rotations of the retainer plate 60. In
Referring to
As will be appreciated, the chain assembly 24 is simple in construction and can be readily and efficiently used with a rolling door to control or regulate the speed at which a door is raised or lowered. With the optional governor or fly lock out pin the unit can also stop a rolling door from free fall thus avoiding potential injury or harm or damage to property.
The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
