Spring counterbalance method and apparatus for variably biasing a dock leveler
First Claim
Patent Images
1. A dock leveler, comprising:
- a base assembly;
a ramp assembly configured to rotate from a generally vertical stored position to one or more lowered operating positions, wherein the ramp assembly is pivotally coupled to said base assembly at a pivot point located generally at one end of the ramp assembly; and
,a counterbalance assembly comprising;
a first anchor point;
a second anchor point;
a flexible member and,a biasing member having a central longitudinal axis defining a line of action, wherein the biasing member is coupled at one end to the ramp assembly at said first anchor point and to the flexible member at an other end of the biasing member, and the flexible member is connected to the base assembly or a dock at the second anchor point, and wherein along the line of action, at least one effective anchor point is defined as a point on the line of action proximate to a contact point between the flexible member and a cam surface.
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Abstract
A counter balance mechanism for a mechanically-operated, vertically-storing dock leveler that can upwardly bias the dock leveler at desired angles of rotation and downwardly bias the dock leveler at other angles of rotation, and neutrally bias the dock leveler at yet other angles of rotation. A method for assisting the operation of a mechanically-operated, vertically-storing dock leveler of desirable simplicity is also provided.
44 Citations
16 Claims
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1. A dock leveler, comprising:
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a base assembly; a ramp assembly configured to rotate from a generally vertical stored position to one or more lowered operating positions, wherein the ramp assembly is pivotally coupled to said base assembly at a pivot point located generally at one end of the ramp assembly; and
,a counterbalance assembly comprising; a first anchor point; a second anchor point; a flexible member and, a biasing member having a central longitudinal axis defining a line of action, wherein the biasing member is coupled at one end to the ramp assembly at said first anchor point and to the flexible member at an other end of the biasing member, and the flexible member is connected to the base assembly or a dock at the second anchor point, and wherein along the line of action, at least one effective anchor point is defined as a point on the line of action proximate to a contact point between the flexible member and a cam surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A counterbalance assembly for a mechanically-operated, vertically-storing dock leveler having a rotating ramp assembly, comprising:
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ramp means configured to pivot generally about one end of the ramp means; tension means for counterbalancing the ramp means of a dock leveler, wherein the tension means has a first end and a second end; means for fixedly coupling said first end of said tension means to the ramp means at a first anchor point; means for flexibly coupling said second end of said tension means to a base assembly of the dock leveler at a second anchor point, wherein the first anchor point and second anchor point define a direct line of action; and
,means for camniing configured to selectively engage the means for flexibly coupling along a side of the flexibly coupling means when the ramp means is located such that the tension means is deflected away from the direct line of action when the tension means and the tension means is operatively connected to the means for flexibly coupling and the ramp assembly rotates, wherein counterbalance characteristics of the ramp means change as the position of the ramp means changes and the tension means is deflected away from the direct line of action. - View Dependent Claims (15, 16)
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Specification