Patent ID: 7645000
Filing Date: 2010-01-12
Classification: A47B,F16D

Abstract:
1. A driving mechanism for use on a storage unit movable about a floor surface, said driving mechanism comprising: a frame; at least one driving wheel for engaging the floor surface, said driving wheel rotatably carried by said frame; a rotary first braking member rotatably carried by said frame and operatively connected to said driving wheel so as to rotate in synchronism therewith, said first braking rotary member defining at least one first interlock member; a gravity-biased second braking member defining at least one second interlock member and movably mounted to said frame so as to be movable between a standby position in which said second interlock member clears said first interlock member, and a braking position in which said second interlock member is interlocked with said first interlock member to block rotation of said rotary first braking member and thus of said driving wheel, said second braking member being biased under the action of gravity towards said braking position when it is in said standby position; a brake control member mounted to said frame, said brake control member movable between: wherein said second braking member is free of any mechanical structural link with said brake control remember wherein said second braking member is pivotable relative to said frame about a pivot axis between said standby and braking positions, and defines a center of gravity horizontally offset relative to said pivot axis in said standby position; wherein said first braking member is mounted on a shaft rotatably mounted to said frame; wherein said first braking member is a toothed wheel mounted to said shaft and rotating as one therewith, said toothed wheel comprising a number of radially-oriented peripherally spaced-apart teeth, with a gap being formed between each two consecutive teeth, said teeth and said gaps forming said at least one first interlock member; wherein said second braking member is a braking block pivotally mounted to said frame adjacently to said toothed wheel, said braking block defining a free outer end forming said second interlock member, and wherein when said brake control member is moved to said release position, said braking block is forced towards said braking position under the action of gravity whereby said braking block free outer end comes into gravity-borne interlocking engagement in one of said gaps formed between two consecutive ones of said toothed wheel teeth wherein said braking block is L-shaped and is pivotally attached to said frame at an inner end located opposite said free outer end; wherein said brake control member is a linkage assembly carried by said frame and comprising a connecting rod defining a distal end destined to project outwardly of the storage unit, and a proximal end pivotally connected to a retaining member, said retaining member being in turn pivotally carried by said frame; wherein said connecting rod can be axially moved between a first position and a second position relative to said frame, the axial movement of said connecting rod controlling the pivotal movement of said retaining member; and wherein when said connecting rod is in said first position, said retaining member engages said braking block and retains it in said standby position against the action of gravity, and when said connecting rod is moved to said second position, said retaining member is pivoted away from and clears said braking block to allow gravity-borne interlocking engagement thereof with said toothed wheel.