Cơ giới hóa công tác vận chuyển người và hàng hóa cho toà nhà chung cư, văn phòng cho thuê và siêu thị

Features of escalators and moving walks Because escalators and walks shout serve people of all ages and abilities, they must be inherently safe. It has been determined that escalators are generally safer than stairs and comparable statistics for moving walkways have not been compiled. Escalator safe has been the result of experience, with much research and development. Early escalators, for example, had wide step cleats with grooves of about ½ in. (13 mm). Well-designed modern escalators have cleats no more than ¼ in. ( 6 mm) wide and grooves not less than 3/8 in. (9 mm) deep as required by the A17.1 code. These cleats and grooves are “combed” as they move at the top or lower landing to dislodge soft shoe soles and debris to avoid accidents ( figure 9.10). The A17.1 code requires the same type of combing action on moving walks. Escalator step risers are also cleated so that people who ride with their does against the riser will not have their soft shoe soles drawn between the steps as they straighten out (figure 9.10). The footwear shown in the illustration may be dated but the hazard is amply illustrated. As the lower step rises to meet the upper step at the exit of an up escalator, the friction of the material against the moving step riser will cause the shoe material to be drawn into the gap between the steps. The combing action will oppose this downward motion. The same hazard exists as the side of the steps travels along the skirt panel. Some people ride with their feet pressed against the side of an escalator. As the steps fltaten there is a possibility of a soft shoe such as a sneaker or rainwear being drawn between the step and the side. If this occurs, a switch actuated by the deflection of the side should stop the escalator ( figure 9.11). escalator and walk brakes must be designed to stop the fully loaded treadway as quickly as possible to minimize personal injury. A promising development of raised treads adjacent to the skirts discourages riders from pressing their feet against the skirt. The treads need only be raised about 1/8 in. (3 mm). In addition the treads adjacent to the skirt and at the leading and trailing edges of each step can be marked in a high visibility color such as yellow or orange so that riders will avoid these hazardous areas. All escalators and walkways should be reversible so that their capacity can be utilized in either direction. Reversing switches are key operated and generally located at the top or bottom landing in the newel post. An emergency stop switch is required for escalators and walkways and its location is prescribed by A17.1. To discourage mischief, a hinged plastic cover can be used over the stop switch. Lifting the cover sets off an alarm and the stop switch can be then operated. The alarm can also be monitored at a security station so emergency personnel can be alerted. The loading and exiting levels of escalators and walks should be extended so that passengers can grasp the handrail and become adjusted to the speed of the steps as they board. Two and one – third flat steps should be provided as a minimum before the incline begins, 2 and 1/3 flat steps are not a manufacturer’s standard and need to be specified. Illumination under the steps which shines through the gap between steps is an effective safety feature to provide tread delineation of the points of embarcation. Balustrade treatments have undergone radical changes since the early days of escalators. A wide variety of materials is a vailable for the balauctrading of both escalators and walkways, including stainless steel, bronze, glass ( also called crystal balystrading ), aluminum in various colors, laminated plastics, tinted glass, lighted glass panels, and fiberglass material. Haindrail are now being made in variety of colors. The basis oval section of the handrail has remained unchanged, as this shape seems to provide the firmest and most comfortable gripping surface. The entry of the handrail into the newel is made as inaccessible as possible to minimize hazard, especially to curious children ( figure 9.12). Escalator Operation Escalators are generally manually started and stopped by an attendant using a keyed switch located at the top or bottom of an escalator. The attendant can ensure that no one is on the escalator and start it in the desired direction. Stopping is also done by an attendant who can ensure that no one is riding at the time. The stop can be somewhat harsh since this stop is the same as that used for emergency stopping if the various safety switches are actuated. It is possible to equip escalators with two levels of stopping deceleration, the emergency stop and a controlled stop which extends the stopping distance of the steps and is somewhat gradual. The controlled stop is limited to a deceleration of about 1.5 fpt2 ( 0.46mps2),whereas an emergency stop deceleration is about 3 fps2 ( 0.9 mps2). The controlled stop was introduced in the United States by the consulting engineering firm of Jaros, Baun and Bolles. William S. Lewis, the partner in charge of vertical transportation, became concerned about escalators in an office building during a fire emergency whereby the escalators, if not stopped, could bring people in to a smoke involved floor. By specifying and encouraging the development of a controlled stop, it is now possible to stop the escalators if a smoke detector is actuated, or stop them from a remote control if a fire emergency occurs. The controlled stop has been applied on a number of escalators in various buildings with excellent results. With a controlled stop and with future development of a gradual, controlled start, it becomes feasible to consider escalator that can be automatically started and stopped and to have a single escalator serve traffic in both the up and down directions. This is presently done without controlled starting and stopping and is accomplished by means of floor treadle or mat switches at the top and bottom landings of escalators and may not be in compliance with safety codes. The operation of a stopped escalator is initiated, for example, by a person stepping on the top treadle and starting the escalator in the down direction. When the escalator starts, the passenger can travel down and once he or she steps off and passes the lower treadle, the escalator will shop a preestablished time after the lower treadle switch time after the lower treadle switch is actuated. Similarly, a passenger wishing to go up steps on the lower treadle and starts the escalator in the up direction, and it will stop a short time after the upper treadle switch is actuated. The hazard is that nay person who may have bypassed one of the treadles may be walking on an escalator and the abrupt start or stop will upset that person. With both a controlled start and stop. That hazard could be minimized. A single reversible escalator can provide a cost effective vertical transportation solution to an application where heavy traffic in one direction is expected at any time and in the opposite direction at another tim L¾P §ÆT THANG M¸Y Nh÷ng c«ng t¸c cÇn lµm tr­íc khi l¾p ®Æt thang m¸y. - NghiÖm thu giÕng tha ng; - NghiÖm thu buång ®Æt m¸y; - NghiÖm thu phÇn ®iÖn vµ phÇn tiÕp ®Þa. 2. §­a bé têi kÐo, vËt t­ vµ thiÕt bÞ lªn buång m¸y. Cã hai ph­¬ng ¸n ®Ó ®­a bé têi kÐo, vËt t­ vµ thiÕt bÞ lªn buång ®Æt m¸y. Ph­¬ng ¸n 1: Dïng cÇn trôc ®­a lªn sµn tÇng m¸I vµ ®­a vµo buång m¸y. Ph­¬ng ¸n nµy chØ thùc hiÖn ®­îc khi cÇn trôc cã ®ñ tÇm víi ®Ó ®­a bé têi vµ tñ ®iÖn ®iÒu khiÓn ®Õn tËn cöa cña buång ®Æt m¸y, ®ång thêi cöa ph¶I ®ñ lín ®Ó cã thÓ ®­a ®­îc m¸y vµo, nÕu kh«ng, viÖc ®­a bé têi kÐo qua sµn m¸I vµo buång m¸y sÏ rÊt phøc t¹p, ®Æc biÖt mÆt sµn buång m¸y l¹i cao h¬n sµn m¸I th× l¹i cµng phøc t¹p h¬n. Ph­¬ng ¸n 2: Dïng pal¨ng ®iÖn hoÆc têi ®iÖn, hoÆc têi quay tay ®Ó ®­a bé têi kÐo vµ c¸c thiÕt bÞ vËt t­ lªn buång ®Æt m¸y qua giÕng thang. Ph­¬ng ¸n nµy hoµn toµn chñ ®éng vµ kh«ng phô thuéc vµo ®é cao cña buång ®Æt m¸y. Sµn ®Æt m¸y khi ®æ bªt«ng ph¶I trõ lç ®Ó ®­a bé têi kÐo lªn, kÝch th­íc lç tèi thiÓu ph¶I ®ñ lín ( Ýt nhÊt 1050 x 1200), phô thuéc vµo tõng thang. 3.Giµn gi¸o Theo truyÒn thèng trong l¾p ®Æt thang m¸y, th­êng dïng giµn gi¸o ®Ó phôc vô cho c«ng viÖc l¾p ®Æt trong giÕng thang. Giµn gi¸o cã thÓ lµ giµn gi¸o kim lo¹i hoÆc gç. Tïy theo kÕt cÊu cña giÕng thang vµ kh¶ n¨ng cung øng vËt t­ víi dông cô thi c«ng cña ®¬n vÞ l¾p ®Æt ®Ó chän mét trong hai lo¹i trªn. Giµn gi¸o ®­îc ®Æt tõ d­íi lªn, cø c¸ch mét kho¶ng tõ 2 ®Õn 3 mÐt cã mét sµn thao t¸c. Sµn thao t¸c cã thÓ b»ng thÐp hoÆc b»ng gç, gi÷a c¸c sµn cã thang leo. Khi l¾p giµn gi¸o ph¶I tÝnh to¸n ®Ó cã thÓ thao t¸c tÊt c¶ c¸c c«ng viÖc trong giÕng thang mét c¸ch dÔ dµng, thuËn tiÖn. Kh«ng mÊt æn ®Þnh, kh«ng ¶nh h­ëng tíi vÞ trÝ c¸c d©y däi vµ kh«ng ph¶I dÞch chuyÓn trong suèt c¶ qu¸ tr×nh l¾p ®Æt. Theo kinh nghiÖm bè trÝ giµn gi¸o nh­ h×nh: NÕu giµn gi¸o b»ng gç ph¶I chó ý ®¶m b¶o ®é cøng v÷ng vµ ®é bÒn. Theo tiªu chuÈn TCVN 5744- 1993 giµn gi¸o ph¶I chÞu ®­îc t¶I träng kh«ng d­íi 2,5 KN/ m2 sµn. Còng cã thÓ dïng giµn gi¸o di ®éng ®Ó l¾p ®Æt trong giÕng thang, nh­ng ph¶I hÕt søc chó ý cã biÖn ph¸p an toµn lao ®éng. §Æc biÖt, nh÷ng thang m¸y cã hµnh tr×nh lín th× rÊt cã hiÖu qu¶, gi¶m ®­îc nhiÒu chi phÝ vËt t­ vµ nh©n c«ng. 4.B¶ng däi Tïy theo ph­¬ng ¸n l¾p ®Æt mµ cã c¸c ph­¬ng ¸n lµm b¶ng däi kh¸c nhau. Nh­ng tÊt c¶ ®Òu ph¶I theo mét nguyªn t¾c chung lµ d©y däi ®­îc dïng lµm chuÈn theo ph­¬ng th¼ng ®øng ®Ó lÊy dÊu khoan lç vµo dÇm (v¸ch) bªt«ng phôc vô cho c«ng viÖc l¾p b¶n m· ray cabin, ray ®èi träng vµ l¾p cöa tÇng. VËt t­ dïng ®Ó thi c«ng b¶ng däi cã thÓ lµ: nh÷ng thanh thÐp ®Þnh h×nh, nh÷ng thanh gç hoÆc tÊm gç d¸n cã ®é dÇy, ®é cøng cÇn thiÕt. Trªn c¬ së c¸c kÝch th­íc ®· cho trong b¶n vÏ l¾p ®Æt cña nhµ chÕ t¹o cung cÊp, cô thÓ lµ kho¶ng c¸ch gi÷a t©m ray cabin vµ ray ®èi träng, gi÷a ray cabin vµ mÐp ng­ìng cöa cabin hay mÐp trong cña ng­ìng cöa tÇng ®Ó cè ®Þnh nh÷ng kÝch th­íc chuÈn trªn b¶ng däi. H×nh d­íi ®©y lµ b¶ng däi cho lo¹i thang cã ®èi träng ®Æt phÝa sau cabin, cöa cabin vµ cöa tÇng më chÝnh gi÷a lïa vÒ hai phÝa. Sau khi treo b¶ng däi vµo phÝa sµn ®Æt m¸y, ph¶I c¨n chØnh c¸c kho¶ng c¸ch chÝnh x¸c vÒ c¸c phÝa thµnh giÕng thang, sao cho ®¶m b¶o c¸c kho¶ng c¸ch l¾p ®Æt an toµn. Khi c¸c d©y däi ®· hoµn toµn æn ®Þnh, cã thÓ cè ®Þnh c¸c d©y däi vµo khung ®Æt phÝa d­íi ®¸y giÕng thang. C«ng viÖc l¾p ®Æt tiÕp theo cã thÓ tïy theo ®iÒu kiÖn thùc tÕ ë c«ng tr­êng, thêi tiÕt… ®Ó chän tr×nh tù l¾p tiÕp theo võa cã hiÖu qu¶ cao, võa an toµn. Th«ng th­êng, ë c¸c n­íc trªn thÕ giíi ®Òu l¾p c¸c cöa tÇng tr­íc, sau ®ã míi l¾p ray vµ c¸c bé phËn cßn l¹i trong giÕng thang. L¾p theo tr×nh tù nµy ®¶m b¶o an toµn h¬n, tr¸nh ®­îc nh÷ng rñi ro cho ng­êi vµ thiÕt bÞ do nh÷ng vËt l¹ r¬I vµo giÕng thang. Nh­ng ng­îc l¹i v× kh«ng gian giÕng thang rÊt chËt hÑp vµ bÝ, thiÕu kh«ng khÝ nªn ë ViÖt Nam vµo nh÷ng thêi ®iÓm nãng, oi vµ ®Æt biÖt khi thi c«ng hµn trong giÕng thang th× rÊt cã h¹i cho søc kháe cña c«ng nh©n. V× vËy, còng cã thÓ l¾p ray cabin vµ ray ®èi träng tr­íc sau ®ã míi l¾p c¸c cöa tÇng, nh­ng hÕt søc l­u ý phßng ngõa nh÷ng rñi ro do c¸c vËt l¹ r¬I vµo giÕng thang. e, such as in a train station or a commuter parking garage.