Two Lid Counterbalance Mechanism

Abstract

A cover mounting combination hinge and counterbalance mechanism, wherein two lids or covers may be carried and counterbalanced by a single mechanism.

Description

SUMMARY OF THE INVENTION

The present invention is primarily directed towards a mechanism adapted to hingedly support a pair of lids on a cabinet for swinging movement in opposite directions between horizontally disposed closed and vertically disposed open positions, wherein the torque effects of gravity on the lids may be counterbalanced.

In the preferred form of the present invention, both lids are counterbalanced and their swinging movements dampened by a common friction device. Counterbalancing of lids having substantially varying gravity induced torque effects, due to weight and/or size considerations, may be effected by employing a pair of coil type compression springs, wherein a first spring is employed to counterbalance a first or relatively heavy lid and both springs working in opposition to one another are employed to counterbalance a second or relatively lightweight lid.

While the cover mounting combination hinge and counterbalance mechanism of the present invention will be primarily described with reference to a two lid construction, it will be understood that the mechanism incorporates novel features having utility in a single lid construction.

DRAWINGS

The nature and mode of the present invention will now be more fully described in the following detailed description taken with the accompanying drawings wherein:

FIG. 1 is a side elevational view of the preferred embodiment of the lid mounting combination hinge and counterbalance mechanism of the present invention;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a sectional view taken generally along line 4--4 in FIG. 2;

FIG. 5 is a view similar to FIG. 4, but showing the first lid in open position;

FIG. 6 is a view similar to FIG. 4, but showing the second lid in open position; and

FIG. 7 is a graphical comparison of the torque effect curves of the lids and the mechanism of the present invention without snubbing effects.

DETAILED DESCRIPTION

Reference is now made particularly to FIGS. 1-3, wherein the lid mounting combination hinge and counterbalance mechanism of the present invention is generally designated as 10. Mechanism 10 includes a stationary or base hinge part 12, which is to be suitably fixed to a cabinet, not shown; a first moveable hinge part 14 for supporting a first or front cabinet opening covering lid 16; a second moveable hinge part 18 for supporting a second or rear service cabinet opening covering lid 20; a counterbalance and motion snubbing assembly 22; and a single hinge pin 24 for simultaneously supporting hinge parts 14 and 18 on hinge part 12, whereby lids 16 and 20 are supported for independent vertical swinging movements in opposite directions from essentially horizontally disposed lid closed positions into essentially vertically disposed lid opened positions. For any given installation, one or more of mechanisms 10 may be employed, depending on the weights and/or dimensions of lids 16 and 20.

As will be apparent from viewing FIGS. 1, 2 and 4, the upper end of stationary hinge part 12 is bifurcated in construction, thereby to define parallel side flange members 26, which are formed with aligned bearing openings for receiving opposite ends of hinge pin 24 and aligned horizontally elongated slot openings 28 for receiving opposite ends of a second hinge pin 30. Moreover, facing surfaces of flange members 26 are shaped to define shoulder abutments or stops 32, only one being shown in FIGS. 4-6; and front end edge surfaces of flange members 26 define abutments or stops 34.

First hinge part 14 is best shown in FIGS. 1-3 as being of generally inverted U-shaped cross sectional configuration including a top or connecting flange portion 36 and a pair of identically configured depending leg flange portions 38. Leg flange portions 38 are formed adjacent their forward ends with aligned cutouts 40 for use in supporting the front end of assembly 22; whereas the rear ends of the leg flange portions are formed with aligned aperatures to receive hinge pin 24 and adapted to engage with shoulder abutments 32 to define the full opening position of lid 16. First hinge part 14 may be suitably fixed to lid 16, as by fastener devices, not shown, which extend through side flanges 38a carried by each of leg flange portions 38.

Assembly 22 is best shown in FIGS. 4-6 as including first and second coil type compression springs 42 and 44, respectively, which are arranged concentrically of a stepped-diameter bolt 46 having a screw threaded intermediate portion 48. Spring 42 is arranged to bear adjacent its opposite ends on a spring plate or adjustment nut 50 threaded onto bolt portion 48 and a cup retainer 52; cup retainer 52 in turn bearing on one end of a resiliently deformable, plastic brake shoe 54, which is arranged concentrically of and in frictional engagement with the front end portion of bolt 46. The forwardly facing end of shoe 54 is arranged in engagment with the converging inner or bearing walls of a through bored, cup shaped member 56, which is in turn received within opening 58 of a U-shaped mounting plate 60. The specific construction of shoe 54 forms no part of the present invention; such shoe having been previously described in commonly assigned U.S. Pat. No. 3,187,374.

As best shown in FIGS. 1 and 3, opposite ends of mounting plate 60 are formed with dimpled ears 62, which extend outwardly through cutouts 40 and serve to support the forward end of assembly 22 on leg flange portions 38 for relative vertical pivoting or tilting movements. As will be apparent from viewing the drawings, bolt 46 passes freely through member 56 and mounting plate opening 58 and thus is free to reciprocate, tilt and undergo rotary adjustment movements relative to first hinge part 14.

The rear end portion of bolt 46 is rotatably received with a bore opening 64 formed in a connector 66; the latter being pivotally mounted by second hinge pin 30 and formed with a guide extension or finger 68 arranged to extend co-directionally with bore opening 64.

Again referring to FIGS. 4-6, it will be seen that spring 44 is arranged to bear adjacent its opposite ends on a stop plate 70, which normally lies in engagement with connector 66, and on a washer 72, which lies in engagement with bolt shoulder 74 adjacent threaded portion 48; stop plate 70 and washer 72 being apertured to freely receive bolt 46. Both stop plate 70 and spring plate 50 are formed with top edge opening slots 76, which are dimensioned to slidably receive guide extension 68. The construction is such that upon rotations of bolt 46 with mechanism 10 in its inoperative or lid closed condition shown in FIG. 4, spring plate 50 is constrained by guide extension 68 for reciprocating movements lengthwise of the bolt for the purpose of varying the extent to which spring 42 is initially compressed, whereby permitting adjustments of its counterbalancing effects on both of lids 16 and 20. It will be appreciated that in the preferred form of the invention, adjustments of spring 42 do not directly effect spring 44, and that spring 44 is subject to compression stress only during opening and closing movements of lid 20 after stop plate tabs 70a have been placed in constrained engagement with stops 34.

Again referring to FIGS. 2, and 4-6, it will be understood that in the preferred form of the invention connector 66 is also coupled to hinge part 18 by means of a pair of parallel links 80, which are joined intermediate their ends by a cross piece 82. Specifically, forward ends of links 80 are pivotally supported relative to connector 66 by second hinge pin 30, whereas the rearward ends of the links are pivotally supported by a third hinge pin 84 carried by second hinge part 18. In this construction, hinge pins 24, 30 and 84 are maintained essentially parallel.

Operation of mechanism 10 will now be described with reference to FIGS. 4-7. With both of lids 16 and 20 in their closed positions illustrated in FIG. 4, spring 42 is subject to maximum compression, as determined by prior adjustments of spring plate 50, and spring 44 is preferably loose or in a non-compressed state. The moments produced by spring 42 are however, less than the torque effects of gravity on lids 16 and 20, as indicated in FIG. 7, and thus the lids are normally maintained by gravity in a tightly closed condition.

When it is desired to open lid 16, an operator must initially apply sufficient lifting force to counterbalance gravity induced torque effects not compensated for by spring 42, until a lid open angle of about 5.degree.-15.degree. is reached. Thereafter, the variable moment produced by spring 42 is sufficient to completely counterbalance the progressively decreasing lid torque until upward movement of the lid is arrested by engagement of leg flange portions 38 with shoulder abutments 32, as shown in FIG. 5. Throughout the range of movements of lid 16, second hinge pin 30 is maintained adjacent the front end of slots 28 by the weight of lid 20 acting through hinge part 18 and links 80.

When it is desired to open lid 20, an operator must again initially apply sufficient lifting force to counterbalance gravity induced torque effects not compensated for by spring 42 until a lid open angle of between about 5.degree. and 15.degree. is reached; spring 44 being ineffective until stop plate tabs 70a are moved into engagement with stops 34, as a result of rearward movement of connector hinge pin 30 within slots 28. Thereafter the variable moment produced by springs 42 and 44 working in opposition is sufficient to counterbalance the lid. By employing springs 44 of various spring constants and by varying the point at which stop plate tabs 70a engage stops 34 during opening movement of lid 20, the counterbalance curves may be precisely tailored to the torque curves of both lids, even though the weight of lid 16 may be considerably in excess of that of lid 20. During opening movements of lid 20, the weight of lid 16 maintains the front end of assembly 22 relatively stationary and second hinge pin 30 is permitted to move rearwardly within slots 28 until it engages the rear ends of such slots, thereby to define the full open position of lid 20. As a practical matter, in the arrangement illustrated lids 16 and 20 may not be raised simultaneously.

While the effect of "snubbing action," which is produced by frictional engagement of shoe 54 with rod 46, on the spring torque curves is not depicted in FIG. 7, it will be understood by reference to above-mentioned U.S. Pat. No. 3,187,374, that such "snubbing" action always opposes movement of the lids. Thus, the "snubbing" action cooperates with the springs to define a counterbalance envelope for each of the lids. When the torque curve of a given lid falls within its associated envelope it is "balanced" and prevented from coasting towards either of its open or closed positions. However, when for instance a portion of the torque curve of a given lid is disposed about its associated envelope, as is preferred during the last degrees of lid closing movement, the lid is not "balanced" and gravity is permitted to force same into a tightly closed position.

Various modifications of the present mechanism are anticipated including the deletion of spring 44 in cases where lids 16 and 20 have similar moments or torque curves. Further, in cases where lid 20 is seldom used or is extremely lightweight, counterbalancing thereof may be dispensed with by deleting links 80 and modifying the base hinge part to prevent lateral displacements of second hinge pin 30. Moreover, for single lid installations, hinge part 18 may be completely dispensed with.

Claims

I claim:

1. A combination counter balance and hinge mechanism for supporting a pair of lids on a cabinet for vertical swinging movements in opposite directions between essentially horizontal closed and essentially vertical open positions, said mechanism comprising:

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

a first movable hinge part adapted to carry a first of said lids;

a second movable hinge part adapted to carry a second of said lids;

means for pivotally connecting said first and second hinge parts to said stationary hinge part whereby to permit independent vertical swinging movements of said lids in opposite directions;

a counter balance assembly; and

means coupling opposite ends of said assembly to said first and second hinge parts, said assembly establishing first and second moments tending to counterbalance the torque effects of gravity on said first and said second lids, respectively, throughout at least a substantial portion of the vertical swinging movements thereof.

2. A mechanism according to claim 1, wherein the torque effect of gravity on said first lid is greater than on said second lid; and said assembly includes a pair of compression springs, a first of said springs establishing said first moment, and said first and second springs working in opposition establishing said second moment.

3. A mechanism for use in counterbalancing first and second lids supported for vertical swinging movements in opposite directions relative to a cabinet between essentially horizontal closed and essentially vertical open positions, said mechanism comprising:

a stationary hinge part;

a first movable hinge part;

a second movable hinge part;

hinge pin means for pivotally connecting said first and second hinge parts to said stationary hinge part whereby to permit independent vertical swinging movement thereof in opposite directions, said first and second hinge parts being coupled to said first and second lids respectively for conjunctive vertical swinging movements when said first and second hinge parts are swung relative to said stationary hinge part as aforesaid;

an elongated bolt extending transversely of said hinge pin means;

first means for providing a slide support for one end of said bolt while permitting relative vertical swinging movements of said one end relative to said first hinge part;

second means for providing an end bearing support for another end of said bolt while permitting relative vertical swinging movements of said other end relative to said second hinge part;

means carried by said bolt intermediate the ends thereof;

a first compression spring disposed about said bolt to bear adjacent opposite ends thereof on said bolt carried means and said first means, whereby to continuously maintain said first compression spring in a compressed state;

a second compression spring disposed about said bolt intermediate said second means and said bolt carried means and being maintained thereby in no more than a minimum state of compression;

stop means positioned for engagement by said second compression spring upon vertical swinging movement of said second part from said horizontal position whereby to effect compression of said second spring intermediate said stop means and said bolt carried means, said first compression spring establishing a first moment tending to counterbalance gravity induced torque effects on said first lid during vertical swinging movements thereof, and said first and second compression springs working in opposition establishing a second moment tending to counterbalance gravity induced torque effects on said second lid during vertical swinging movements thereof.

4. A mechanism according to claim 3, wherein said first and second lids are fixedly carried by said first and second movable hinge parts, and said hinge pin means is a single hinge pin.

5. A mechanism according to claim 4, wherein said second means includes a connector member forming an end bearing support for said other end of said bolt, first pivot pin means, slot means defined by said stationary hinge part, said slot means extending transversely of said hinge pin means and slideably and rotatably receiving said first pivot pin means, second pivot pin means, and link means, said first and second pivot pin means pivotally connecting opposite ends of said link means to said connector member and said second hinge part for relative vertical swinging movement.

6. A mechanism according to claim 3, wherein said bolt carried means includes first and second members, said first member being arranged in bearing engagement with said first compression spring and being threadably carried by said bolt for movement lengthwise thereof whereby to adjustably vary the compression of said first compression spring, said second member being arranged for engagement with said second compression spring and constrained by said bolt for movements lengthwise thereof towards said first member, and said second means end supports said bolt for rotation relative thereto about an axis extending lengthwise of said bolt.

7. A mechanism according to claim 6, wherein said first and second lids are fixedly carried by said first and second movable hinge parts, said hinge pin means is a single hinge pin, said second means includes a connector member forming an end bearing support for said other end of said bolt, first pivot pin means, slot means defined by said stationary hinge part, said slot means extending transversely of said hinge pin means and slidably and rotatably receiving said first pivot pin means, second pivot pin means, and link means, said first and second pivot pin means pivotally connecting opposite ends of said link means to said connector member and said second hinge part for relative vertical swinging movement.