Counterbalance mechanism

• US 4,091,502 A
• Filed: 11/10/1976
• Issued: 05/30/1978
• Est. Priority Date: 11/10/1976
• Status: Expired due to Term

• Current Assignee: Weber Knapp Company
• Original Assignee: Weber Knapp Company
• Inventors: Little, Carl H.
• Primary Examiner(s): Kee Chi, James
• Application Number:
  US05/740,430
• Time in Patent Office: 566 Days
• Field of Search: 16/190, 16/180, 16/1 C, 16/85, 16/141, 16/142, 16/144, 16/145, 49/386, 217/60 R
• US Class Current: 16/273
• CPC Class Codes: E05D 11/1064 with a coil spring perpendicular to the pivot axis
• CPC Class Codes: E05F 1/1261 for counterbalancing
• CPC Class Codes: E05Y 2900/20 for furnitures, e.g. cabinets

Abstract

A counterbalance mechanism including a cabinet mounted stationary hinge part; a movable hinge part pivotally mounted on the stationary hinge part and connected for conjunctive vertical swinging movement with a cabinet lid; and a counterbalance assembly including an adjustable compression spring arranged to bear adjacent its opposite ends on the hinge parts characterized in that the counterbalance assembly is constrained from swinging movements relative to the lid connected hinge part whereby to minimize mechanism installation space requirements.

Claims

1. A mechanism for use in counterbalancing the weight of a lid supported on a cabinet for vertical swinging movements between closed and open positions, said mechanism comprising:

a stationary hinge part adapted to be fixed to said cabinet;

a movable hinge part;

hinge pin means for pivotally connecting said movable hinge part to said stationary hinge part for vertical swinging movements relative to said cabinet about an essential horizontal hinge axis, said movable hinge part being adapted to be coupled to said lid for conjunctive vertical swinging movements when said movable hinge part is swung about said hinge axis;

one of said hinge parts defining cam means, said cam means including a pair of aligned cam elements having cylindrical surface portions arranged in a parallel offset relationship relative to said hinge axis;

the other of said hinge parts being of generally U-shaped configuration including a connecting portion and a pair of parallel leg portions extending therefrom, said connecting portion having a through opening, said leg portions having aligned openings to receive said hinge pin means;

a connector defining cam follower means, said cam follower means including a pair of parallel flange members arranged to straddle said one of said hinge parts, said flange members defining aligned cam follower surfaces arranged for bearing surface-to-surface sliding engagement one with each of said cylindrical surface portions, said cam follower surfaces being planar;

mounting means for mounting said connector for reciprocating movement relative to said other of said hinge parts, said mounting means including a bolt having one end received for bearing engagement within an opening formed in said connector and an opposite end movably supported within said through opening of said connecting portion and a pair of aligned guide pin elements fixed to said connector and slidably received one within each of a pair of aligned guide slots formed in said leg portions, said guide pin elements being arranged essentially parallel to said hinge axis and to intersect the axis of said bolt, said guide slots extending co-directionally with said axis of said bolt and having open ends for receiving said guide pin elements, said axis of said bolt being arranged to intersect the line of said surface-to-surface engagement when said lid is in said closed position; and

spring means arranged to bear adjacent opposite end thereof on said connector and said connecting portion for biasing said cam follower surfaces into surface bearing engagement with said cylindrical surface portions whereby to establish a moment acting about said hinge axis and tending to counterbalance the torque effects of gravity on said lid during said vertical swinging movements thereof.

2. A mechanism according to claim 1, wherein said cam elements are covered with friction reducing plastic sleeves serving to define said cylindrical surface portions, said sleeves being formed with rim portions arranged to engage with facing surfaces of said flange members.