| 摘要 |
A vertically adjustable overbed table including a pedestal, a horizontal table top mounted at the top of the pedestal and a horizontal roller-equipped base platform at the lower end of the pedestal. The pedestal includes an upper outer column which telescopes over a lower inner column, and a pair of constant force springs which are mounted within the columns to maintain the telescoping columns in equilibrium. A clutch assembly is mounted within the top of the upper column which includes a rotatable clutch drum, a clutch spring around the clutch drum and a rotatable spool wound with cable, the spool being connected to the clutch drum so that both rotate together. A depending loop is formed at an intermediate portion of the table which engages a pulley wheel at the lower end of a vertical shaft extending below the clutch assembly within the columns. One point of the depending cable is rigidly affixed to the inner column so that the two columns can be moved telescopically only when the cable spool is free to rotate to pay out and take up equal amounts of cable. Lever means are provided for releasing the tension on the clutch spring so that the clutch drum and the spool are free to rotate so that the table can be lowered. An override assembly is also provided in conjunction with the clutch spring which releases the clutch spring tension when a sufficient downward force is placed on the table top so that the table top can be lowered without utilizing the tension releasing lever means. The table top can be raised by exerting an upward force on the table top sufficient to overcome the equilibrium effect of the constant force spring.
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