Counterbalancing
First Claim
1. Counterbalancing apparatus comprising,a weight W to be counterbalanced movable along a first axis,means for supporting said weight W to be counterbalanced and movable along said axis,at least one upper lever means for pivotal connection to said means for supporting at its upper end,at least one lower lever means for pivotal connection at its lower end to an intermediate pivot point and pivotally connected at its upper end to the lower end of said upper lever means,spring means for providing a counterbalancing force,and means for coupling said spring means to an inside pivotal connection such that a force from said spring means lies along a second axis through said lower lever means in a direction intersecting said first axis,the spring rate RT of said spring means, the weight W to be supported on said means for supporting and the distance L between said inside pivotal connection and said lower level means lower end being related by the equation RT =2W/L,whereby said counterbalancing apparatus comprises a self-contained counterbalance mechanism that, neglecting minimal effects of friction, manufacturing inaccuracies and strains, substantially exactly counterbalances said weight W over the linear range of travel of said weight along said first axis.
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Abstract
A counterbalancing mechanism allows a weight or constant force to be counterbalanced for any practical linear range of travel, including means for effortlessly adjusting the mechanism for a constant force or load of any practical magnitude. A load support slides along an axis substantially passing through a fixed lower pivot point. The load support member is pivotally connected to the top end of an upper lever arm. The upper lever arm is pivotally connected by a horizontal link to the upper end of a lower lever arm that is pivotally connected to the fixed point. A pully that may swivel about its swivel axis embraces the axis and guides a cable connected to the horizontal link at one end to a spring assembly at the other end. The spring assembly may be adjusted.
64 Citations
19 Claims
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1. Counterbalancing apparatus comprising,
a weight W to be counterbalanced movable along a first axis, means for supporting said weight W to be counterbalanced and movable along said axis, at least one upper lever means for pivotal connection to said means for supporting at its upper end, at least one lower lever means for pivotal connection at its lower end to an intermediate pivot point and pivotally connected at its upper end to the lower end of said upper lever means, spring means for providing a counterbalancing force, and means for coupling said spring means to an inside pivotal connection such that a force from said spring means lies along a second axis through said lower lever means in a direction intersecting said first axis, the spring rate RT of said spring means, the weight W to be supported on said means for supporting and the distance L between said inside pivotal connection and said lower level means lower end being related by the equation RT =2W/L, whereby said counterbalancing apparatus comprises a self-contained counterbalance mechanism that, neglecting minimal effects of friction, manufacturing inaccuracies and strains, substantially exactly counterbalances said weight W over the linear range of travel of said weight along said first axis.
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18. Counterbalancing apparatus in accordance with claim and further comprising a pantagraphic linkage for coupling said upper lever means to said means for supporting.
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19. Counterbalancing apparatus comprising,
a source of a force source providing a force W to be counterbalanced movable along a first axis, means for supporting said force source providing said force W to be counterbalanced and movable along said first axis, at least one first lever means for pivotal connection to said means for supporting at a first end of said first lever means, at least one second lever means for pivotal connection at a first end of said second lever means to an intermediate pivot point and pivotally connected at a second point of said second lever means to a second point of said first lever means, spring means for providing a counterbalancing force, and means for coupling said spring means to an inside pivotal connection such that a force from said spring means lies along a second axis through said second lever means in a direction intersecting said first axis, the spring rate RT of said spring means, the force W and the distance L between said inside pivotal connection and said second lever means first end being related by the equation RT =2W/L, whereby said counterbalancing apparatus comprises a self-contained counterbalance mechanism that, neglecting minimal effects of friction, manufacturing inaccuracies and strains, substantially exactly counterbalances said force W over the linear range of travel of said force source along said first axis.
Specification