COUNTERWEIGHT SYSTEM

Abstract: A counterweight system for a device (10) having two spaced apart frame members (13) on which is supported a removable component (34). Extending toward one another from a bottom portion (20) of each frame member (13) are projections (22), these being positioned a spaced distance beneath said component (34). Supported on these projections (22) are a plurality of thin removable counterweights (26). The number, and hence total weight, of these counterweights (26) may easily be changed upon removing the component (34). The present invention provides a variable weight counterweight system yielding a lowered center of gravity and is especially applicable to battery powered lift trucks (11) and the like.

Description: De.s.cri ion Counterweight System Technical Field This invention relates generally to counter- weights for load lifting vehicles and more particularly to counterweights for battery-powered lift trucks. Background Art It is well known that the center of gravity of any vehicle must be maintained within the vertical projection of an area whose perimeter is defined by the outermost wheels of that vehicle, failing which the vehicle lacks stability. Preventing this is a matter to which great attention is paid in the design and opera¬ tion of load lifting vehicles. Such vehicles, lift trucks, for example, must by 'their very nature lift loads positioned outside the area in which their center of gravity must be maintained. Lifting such a load results in a shift of the center of gravity bringing about a lessening of stability. Should the operator attempt to lift too large a load the vehicle will become unstable. One means of alleviating this problem involves the use of counterweights. Weights not otherwise required for the operation of the vehicle are placed on a side of the vehicle opposite the load to counter¬ balance the load resulting in a more stable, albeit heavier, vehicle. Typical counterweight systems for lift trucks are disclosed in U.S, Patent 3,061,034 issued to Eoyt on October 3.0, 1962, U.S. Patent 3,367,4-41 issued to Schuster et al on February 6, 1968, U.S. Patent 3,787,086 issued to Cosby on January 22, 1974, and U.S. Patent 4,067,415 issued to Samide on January 10, 1978. Known counterweight systems used to date have generally served to position counterweights as far from, the load lifting portion, of the lift truck as possible, See, for example, U.S t Patent 3,367,441. While this serves to mitigate potential decreases in the longi-* tudinal stability of the vehicle, it does not necessar*-- ily help alleviate possible lessening of stability in a direction transverse to the longitudinal axis of the vehicle. This side-to-side instability of presently available lift trucks is a problem. It would be bene¬ ficial to position a counterweight so as to- optimize both longitudinal and transverse stability. Many existing counterweight systems, such as that disclosed in previously cited U.S. Patent -4,067,415, have only a single counterweight which may be detached. Were a lift truck to be in use solely for transporting light objects, a heavy counterweight would not only be unnecess ' ary but could prove detrimental. It would be advantageous to have a counterweight system in which the counterweight would be of selectively variable weight. It would be further advantageous if such variation could be made without affecting the outer dimensions of the vehicle. U.S. Patent 3,367,441 discloses a counter- weight box in which scrap iron may be placed. While this does provide for a counterweight of variable weight it does not provide for a compact counterweight of readily and accurately alterable weight. The present invention is directed to over¬ coming one or more of the problems as set forth, above. Disclosure of the Invention In one aspect of the present invention a frame has two spaced apart members. Each of these members has an upper surface portion and a bottom portion with an inwardly extending projection thereon. A component is \3ϊ -E A CT removably supported on the upper sur ace portions and at least one counterweight is supported on the proje.cti.ons- beneath the component. Brief Description of the Drawings Fig. 1 is a diagrammatic side elevational view of a lift truck having a portion broken away therefrom incorporating an embodiment of the present invention; and Fig. 2 is a transverse diagrammatic sectional view of the bottom portion of the lift truck of Fig. 1 taken along line II-II of Figure 1. Best Mode for Carrying Out the Invention Referring to the. drawings a counterweighted device is generally indicated by the reference numeral 10. For the purposes of illustratio -a lift truck 11 is shown, however the present invention is also suited for incorporation in many other types of counterweighted vehicles and stationary devices. The lift truck 11 has a frame 12 which in- eludes two spaced apart longitudinally extending frame members 13 running substantially parallel one to the other. These frame members 13 are preferably of hollow substantially rectangular cross section and are each formed of two elongated L-shaped plates, an inner plate 14 and an outer plate 16, joined by welding or other means. .This is best shown in Figure 2. The frame members 13 each, have an upper surface portion 18 and a bottom portion 2Q. Each frame member 13 has a projection 22 extending inwardly from, said bottom portion 20. Pref¬ erably, this projection 22 is an end portion 23 of said outer plate 16. These projections horizontally extend from an innermost upwardly projecting face 24 of each -Λ- frame member 13 toward the. other frame member 13. The frame members 13 are so situated that the two upper surface portions* 18 and the two projections 22 are, respectively, coplanar. These projections. 22 support a- plurality of counterweights 26 placed between the frame members 13, Preferably the counterweights 26 are thin, flat plates of metal. The counterweights 26 have apertures 28 through, which an attachment means such as a plurality of bolts 30 can be used to secure the counter¬ weights 26 to the projections 22. Attaching the counter¬ weights 26 to the frame members 13 in such a fashion also serves to strengthen the frame 12. Alternatively, one or more of the counterweights 26 can be welded to the frame members 13 or simply allowed to rest freely thereon. A sufficient vertical space is provided between the projections 22 and their corresponding frame member upper surface portion 18 to allow the placement of all ~ the counterweights 26 which may potentially be needed without the uppermost portion of the uppermost counterweight 32 reaching an elevation higher than that of the upper surface portion 18. Of course, additional counterweights 26 may be placed elsewhere on the lift truck 11, Resting upon the upper surface portions 18 of the frame members 13 is a vehicle component 34 such as a battery unit. There is preferably no contact between the battery unit and either a, counterweight 26 o -the bolts 30, In the best application of the present invention the vehicle component 34 is readily removable so as to provide ready access to the counterweights 26, It is to be noted that the frame members 13 extend a longitudinal distance, sufficient to support said battery unit 34, a front axle 36 and a rear axle 38, The counterweights. 26 may be advantageously posi¬ tioned at an elevation on said lift truck 11 lower than the elevation of, said axles 36 and 38, these elevations being with respect to the ground upon which the lift truck 11 rests. It should be understood that the present invention can differ as would be obvious to one skilled in the art without departing from the claims. Industrial Applicability The present invention provides a low profile counterweight or auxiliary counterweight system best suited for applications requiring space conservation, a low center of gravity, and simplicity and swiftness in altering the degree to which a device is counterweighted. By placing the counterweights 26 in the space elevationally bounded by the frame member upper surface portion 18 and the bottom portion 20, the counterweights 26 are positioned as low as is possible on the vehicle 10 relative to the surface upon which the vehicle 10 rests without altering the ground clearance thereof. The center of gravity of the vehicle 10 is thereby maximally lowered per unit weight of counterweight 26 added-. Additionally, these counterweights can be placed as far rearwards on the vehicle 10 as is possible to improve longitudinal stability. It is generally most economical, as is well known in the art, to utilize as light a vehicle 10 as possible for a given application. Counterweighting should therefore be kept to the minimum possible con- sistent with safety. For example, a lift truck 11 moving cartons of volleyballs may require no counter- weighting while one transporting bricks could require massive counterweights. The described embodiment of the present invention permits relatively simple, alteration of the degree to which the lift truck.11 is counter¬ weighted by advantageously positioning these counter¬ weights 26 beneath the battery unit 34. The batteries of most current lift trucks are readily removable. This allows easy access to the counterweights of the present invention. It is envisioned that the same hoisting device utilized for removing and installing the batteries could be used for adding or removing counterweights. Other objects, aspects,- advantages and uses of this invention can be obtained from a study of the drawings, the disclosure and the appended claims. " • r. υ -.t '

Claims: Claims 1, A counterweighted device (.101 comprising; a frame (12). having two longitudinally ex¬ tending spaced apart structurally supportive frame members (.131 each having an upper surface portion (18') 5 and a projection (_22) extending in a direction toward the other of said frame members (131; a component (34) removably supported on said ' upper surface portions (181; and at least one counterweight (26) supported by Q said projections (22) and positioned beneath said component (.34) . 2. The counterweighted device (10) of claim 1 wherein: at least one of said counterweights (26) is removably positioned on said frame (12) . 3. The counterweighted device (10) of claim 1 wherein: at least one of said counterweights (26) is removably attached to said frame (12) by attachment means (30) , 4, The counterweighted device (10) of claim .2 wherein: said counterweights (26) have at least one aperture (281; and said attachment means (30) includes bolts (30) passing into said apertures (.28). 5. The counterweighted device (.10) of claim 1 wherein said counterweighted device (10) is a vehicle. 6. The counterweight device (10) of claim 1 wherein: said counterweighted device (.101 is a lift truck (11) , Ol.IPI 7. The counterweighted frame (.101 of claim 1 wherein: said component (.34) is a battery unit- S. The counterweighted device (10). of claim 1 wherein at least one counterweight (.26) is positioned between and rigidly affixed to said structurally sup¬ portive frame members (131, 9. The counterweighted device CIO) of claim 1 wherein at least one counterweight (.261 is removably rigidly affixed to said structurally supportive frame members (13) , 10. The counterweighted device (101 of claim I wherein a plurality of counterweights (26) one on the other are supported by said projections (22) with each of said counterweights (26) being at an elevation lower than said upper surface portions (18).. 11. A counterweighted vehicle (11) comprising: a frame (12) having two longitudinally ex¬ tending spaced apart structurally supportive frame members (13) ; a front axle (36) and a rear axle (38) sup¬ ported by said frame (12) ; and at least one counterweight (26) supported by said frame (12) and positioned between said axles (36,38), 12, The counterweighted vehicle (.11) of claim II wherein at least one said counterweights C26) is elevationally lower than said axles (.36 and 381.. 13. The counterweighted vehicle (111 of claim. 12 wherein; at least one of said counterweights (.261 s removably positioned on sai frame 02L, 14. The counterweighted. vehicle (111 of claim 13 wherein said counterweighted vehicle (11) is a counterweighted lift truck, 15. The counterweighted vehicle (11) of claim 11 or claim 12 or claim 13 wherein each of said struc¬ turally supportive frame members (131 has an upper surface portion (18) and a projection (22) extending in a direction toward the other of said frame members (13) with said counterweights (26) supported upon said projections (22) , and a component (34) removably sup¬ ported on said upper surface portions (18) . OMPI

Inventors: HAMKO ANDREW S
Applicants: HAMKO ANDREW S, TOWMOTOR CORP
Application year: 1980
Main classification: B62D25
IPC codes: B62D25, B62D49, B66F9