Patent Application
20170101292
Field of the Disclosure
The present disclosure relates generally to a system and method for an elevator safety mechanism and, more particularly, to a system and method for a governor inertia carrier used in activating an elevator safety mechanism.
Description of Related Art
In various elevator installations, a safety mechanism is installed on an elevator car to bring the descending elevator car to a stop under certain conditions, such as an uncontrolled descending of the elevator car. The safety mechanism, when actuated, typically operates upon guide rails between which the elevator car is located. The safety mechanism is actuated by a separate speed governor which is set to trip at a predetermined car speed in the down travel direction.
With reference to
The elevator installation has a governor assembly having a governor sheave 50 which is mounted in a top potion of the elevator shaft and a governor cable 60 wound between the governor sheave 50 and a tail sheave 51. The governor cable 60 is tensioned by means of a tension weight 52 acting on the tail sheave 51.
The governor cable 60 is fixed to the elevator car 10 by a plate 53, which is also connected to a safety mechanism 15 mounted on the elevator car 10 by a governor rope lever 11. In normal operation, such as when the speed of the elevator car 10 is less than a limit speed, the elevator car 10 drives the governor cable 60. Such movement of the governor cable 60 rotates the governor sheave 50. During normal operation, any stress on the plate 53 by a pulling force due to the inertia of the governor cable 60 may be offset by, for example, one or more holding tension springs.
When the speed of the car 10 reaches or exceeds a limit speed by at least a predetermined amount, such as when the car 10 starts to free fall, the governor sheave 50 locks, such as by actuation of centrifugal weights that engage a toothed fixed cylinder, and the governor cable 60 is immobilized. This causes a pulling force on the plate 53, which actuates the governor rope lever 11, which then acts on the safety mechanism 15 to actuate brakes 12 and 13. The brakes 12, 13, in return, engage the rails 30, such as by clamping against the rails 30, to bring the elevator car 10 to a safe stop.
One of the drawbacks of existing safety mechanisms is that inertia of the governor assembly during normal operation can cause unintended activation of the safety mechanism. During normal acceleration of the elevator car, the inertia of the governor rope 60, the sheaves 50, 51, and the tension weight 52 exerts a force on the governor rope lever 11. In certain circumstances, the inertia of the governor assembly can activate the safety assembly even though the elevator car 10 is operated within the limit speed. One solution to this problem is to use one or more holding tension springs to hold a safety arm connected to the governor rope lever 11 and prevent its unintended engagement until the limit speed is reached or exceeded. However, space surrounding the safety mechanism 15 is critical, and multiple tension springs often require more space than what is available. In addition, the force exerted by the springs increases linearly as the safety mechanism is activated, thereby resulting in large activation forces on various components and linkages of the safety assembly.
It would be desirable to provide a new and improved safety mechanism for preventing unintended activation of the safety mechanism due to inertia of the governor assembly.
In view of the disadvantages of the existing safety mechanism, there is a need in the art for an improved safety mechanism that overcomes the deficiencies of the prior art.
In accordance with some embodiments, an elevator governor inertia carrier may include a cartridge having a shaft opening for receiving a shaft through the shaft opening. The cartridge may be configured for fixed attachment to the shaft. The governor inertia carrier may further have at least one force-exerting element associated with the cartridge plate and offset from the shaft opening. The at least one force-exerting element may include a hollow body with an internal cavity extending between a first open end and a second end, an elastically-resilient element retained within the internal cavity, and a contact member at least partially disposed within the internal cavity and in contact with or formed at a first end of the elastically-resilient element. The contact member may be retractable into the internal cavity to compress the elastically-resilient element when a force greater than a restoring force of the elastically-resilient element is applied to the contact member.
In accordance with another embodiment, the second end of the hollow body of the force-exerting element may be open. The second end may be enclosed by an adjustment element that is movably adjustable relative to the hollow body and in contact with a second end of the elastically-resilient element to control compression of the elastically-resilient element between the adjustment element and the contact member. The adjustment element may have a seat for contacting the elastically-resilient element at a first end and a socket for engaging an adjustment tool at a second end. The adjustment element may be movable toward the first end of the hollow body by rotating the adjustment element in a first direction to increase the compression of the elastically-resilient element. The adjustment element may be movable toward the second end of the hollow body by rotating the adjustment element in a second direction opposite to the first direction to decrease the compression of the elastically-resilient element. A locking element may be provided for preventing rotatable movement of the adjustment element relative to the hollow body when the locking element engages at least a portion of the hollow body and the adjustment element.
In accordance with another embodiment, the contact member may have a body with a rounded front end that is extendable from the first end of the hollow body and a radially-outwardly protruding lip that is retained within the interior cavity of the hollow body. A collar may protrude radially-inward from a sidewall of the interior cavity. The collar may have a stop surface that limits a protrusion of the pin from the first end of the hollow body. A detent plate may be facing the bottom surface of the cartridge. The detent plate may have at least one detent shaped to receive the contact member. In a first state, the contact member may be engaged within the detent. In a second state, rotation of the cartridge relative to the detent plate may force the contact member out of the detent and at least partially into the interior cavity of the hollow body. The restoring force of the elastically-resilient element may be preset or adjustable.
In accordance with another embodiment, the cartridge may have one or more through holes extending into the shaft opening. A retention member may be provided in each through hole for engaging at least a portion of the shaft and preventing axial movement of the cartridge on the shaft. The shaft opening may have a recessed portion for receiving a shaft support element. The at least one force-exerting element may be removably or non-removably connected to the cartridge. The shaft may be provided such that the shaft is received within the shaft opening of the cartridge. A housing may be provided for receiving at least a portion of the governor inertia carrier. The detent plate may be fixedly mounted to the housing, and the shaft and the cartridge may be rotatable relative to the housing and the detent plate.
In accordance with another embodiment, a safety mechanism for an elevator may include a housing attachable to at least a portion of an elevator car, a safety activation lever connecting a governor assembly to a rotatable shaft disposed within the housing, a braking assembly activated by a rotation of the shaft, and a governor inertia carrier associated with the shaft and the housing. The governor inertia carrier may have a cartridge having a shaft opening for receiving the shaft through the shaft opening. The cartridge may be configured for fixed attachment to the shaft. At least one force-exerting element may be associated with the cartridge. The at least one force-exerting element may have a hollow body with an internal cavity extending between a first open end and a second end. An elastically-resilient element may be retained within the internal cavity. A contact member may be at least partially disposed within the internal cavity such that a first end of the contact member is in contact with or is formed with the elastically-resilient element and a second end of the contact member received in a detent associated with the housing. The contact member may be retractable out of the detent and into the internal cavity when a force greater than a restoring force of the elastically-resilient element is applied to the contact member.
In accordance with another embodiment, a safety mechanism for an elevator may have a housing attachable to at least a portion of an elevator car, a safety activation lever connecting a governor assembly to a rotatable shaft disposed within the housing, a braking assembly activated by a rotation of the shaft, and a governor inertia carrier associated with the shaft and the housing. The governor inertia carrier may have a spring-loaded contact member received within a detent associated with the housing, wherein the spring-loaded contact member is retractable out of the detent when a force greater than a spring-load force of the spring-loaded element is applied to the spring-loaded contact member.
These and other features and characteristics of a governor inertia carrier used in activating an elevator safety mechanism, as well as the methods of operation and functions of the related elements of structures and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only. As used in the specification and the claims, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.
For purposes of the description hereinafter, the terms “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “lateral”, “longitudinal”, and derivatives thereof shall relate to the disclosure as it is oriented in the drawing figures. It is to be understood, however, that the disclosure may assume alternative variations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the disclosure. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting.
Referring to the drawings in which like reference characters refer to like parts throughout the several views thereof, the present disclosure is generally directed to a system and method for an elevator safety mechanism and, more particularly, to a system and method for a governor inertia carrier used in activating an elevator safety mechanism. With reference to
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In some embodiments, the cartridge assembly 148 may be used in combination with a secondary means for controlling the pre-load force that must be overcome before the braking assembly 112 can be activated. For example, the cartridge assembly 148 may be used in combination with one or more tension springs 154 connected at one end to the housing 102, either directly or by way of a bracket 156 or other element, and at the other end to a spring arm 158 that is keyed with the shaft 134. The one or more tension springs 154 can be used to change the pre-load force by either increasing or decreasing the force that must be applied to the cartridge assembly 148 and the one or more tension springs 154 before the braking assembly 112 can be activated. In some embodiments, the one or more tension springs 154 may have a plurality of tension springs 154 connected in series, parallel, or a combination of both. In other embodiments, the one or more tension springs 154 may be substituted by or supplemented with a hydraulic or pneumatic element (not shown) that can be used to augment the pre-load of the cartridge assembly 148.
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A second end 202 of the body 178 is provided opposite the first end 182. The second end 202 has one or more first threads 204 formed on the sidewall of the internal cavity 180 for threadably engaging one or more second threads 206 on an adjustment element 208. The adjustment element 208 has a first end 210 having a seat 212 for engaging one end of a resiliently elastic element, such as a spring 214 provided within the internal cavity 180 of the body 178. The opposing end of the spring 214 engages at least a portion of the pin 192, such as the lip 198 of the pin 192. In some embodiments, the pin 192 may be formed with the spring 214. For example, the pin 192 may be monolithically formed at the terminal end of the spring 214. A second end 216 of the adjustment element 208 has a socket 218 for engaging an adjustment tool (not shown), such as a wrench or a key, for adjusting the position of the adjustment element 208 within the internal cavity 180 of the body 178. In some embodiments, the spring 214 may be a linear spring, a progressive spring, a torsion spring, a volute spring, a leaf spring, a Belleville spring, or any other resiliently elastic member. In other embodiments, the springs 214 may be replaced with a pneumatically or hydraulically charged cylinder having fluid that exerts a force on the pins 192. The stiffness of the spring 214 may be pre-selected based on the desired pre-loading of the pins 192, or the force that is necessary to unseat the pin 192 from the collar 190, that is desired.
The longitudinal position of the adjustment element 208 within the internal cavity 180 can be adjusted by rotating the adjustment element 208 relative to the body 178. For example, rotating the adjustment element 208 in a first direction, such as a clockwise direction, may move the adjustment element 208 from the second end 202 of the body 178 toward the first end 182. Conversely, rotating the adjustment element 208 in a second direction which is opposite to the first direction, such as a counter-clockwise direction, may move the adjustment element 208 from the first end 182 of the body 178 toward the second end 202. Position of the adjustment element 208 within the internal cavity 180 controls the compression of the spring 214. For example, moving the adjustment element 208 toward the first end 182 of the body 178 (i.e., tightening the adjustment element 208) increases the compression of the spring 214 and the amount of force the spring 214 exerts on the pin 192. In other words, compression of the spring 214 increases the force that must be exerted on the pin 192 to displace the pin 192 toward the second end 202 of the body 178 in order to compress the spring 214. Conversely, moving the adjustment element 208 toward the second end 202 of the body 178 (i.e., loosening the adjustment element 208) decreases the compression of the spring 214 and the amount of force the spring 214 exerts on the pin 192. A locking element, such as a lock nut 220, may be provided to prevent movement of the adjustment element 208 once a desired position is set. The lock nut 220 may be threaded onto the adjustment element 208 such that the lock nut 220 engages the second end 202 of the body 178 when fully tightened. Various other locking devices may be provided to prevent the adjustment element 208 from inadvertently moving from its set position.
Referring back to
The governor inertia carrier 146, the housing 102, and/or the detent plate 22 may be made from any high-strength material having desirable strength, wear, and anti-corrosion properties. In some embodiments, the governor inertia carrier 146, the housing 102, and/or the detent plate 22 may be made from metal or plastic. Non-limiting examples of materials suitable for use in forming the governor inertia carrier 146, the housing 102, and/or the detent plate 22 include, but are not limited to, the art-recognized metals, such as high strength steel, stainless steel, aluminum, and alloys thereof, and art recognized high-strength plastics, such as nylon composites, and ultra-high molecular weight polyethylene. Various coatings or surface treatments may be applied to any surface of the governor inertia carrier 146, the housing 102, and/or the detent plate 22. For example, various surfaces of the governor inertia carrier 146, the housing 102, and/or the detent plate 22 may be chrome plated, nickel plated, or heat treated for localized hardening. With reference to
When the limit speed of the elevator installation is reached or exceeded, the governor rope 60 is stopped due to the locking of the governor sheave 50 (
Although the disclosure has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the disclosure is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements. For example, it is to be understood that the present disclosure contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.
