Loader linkage

Claim 2

A material handling device comprising support means, lift arm means pivotally connected to said support means; a bucket pivotally carried by said lift arm means, means for raising and lowering said lift arm means, first means for pivoting said bucket relative to said lift arm means, linkage means extending between said support means and said bucket for automatically limiting the maximum rollback of said bucket to a level position when said lift arm means are raised, said linkage means including a first portion pivotally connected to said first means and to said lift arm means and defining the position of said first means relative to said lift arm means in response to operation of said first means and a second portion having one end pivotally connected to said support means, another end pivotally connected to said bucket, and being pivotally connected intermediate its ends to said first means and defining the pivotal position of said bucket in response to the positions of said lift arm means and said first means relative to said lift arm means.

Claim 3

A material handling device as claimed in claim 1 wherein said first portion of said linkage means includes a first link, first pivot means pivotally connecting one end of said first link to said first means, and second pivot means pivotally connecting the other end of said first link to said lift arm means; and said second portion of said linkage means includes second, third and fourth links, said first pivot means pivotally connecting said second link intermediate its ends to said first means, third pivot means pivotally connecting one end of said third link to said support means, fourth pivot means pivotally connecting one end of said fourth link to said bucket, and additional pivot means pivotally connecting the other ends of said third and fourth links, respectively, to opposite ends of said second link.

Claim 4

A material handling device as claimed in claim 1 wherein said first means comprises hydraulic motor means including a hydraulic cylinder, a piston slideable in said cylinder and having a piston extending out one end thereof and pivotally connected said lift arm means, whereby relative sliding movement of said piston in said cylinder pivots said bucket relative to said lift arm means between maximum rollback and dump positions, and means pivotally connecting said cylinder to said linkage means to limit the maximum rollback of said bucket to a level position when said lift arm means are raised.

Claim 5

A material handling device as claimed in claim 3 wherein said linkage means includes a plurality of pivotally interconnected constant length links.

Claim 6

A material handling device as claimed in claim 4 wherein two of said links are pivotally connected together and to said cylinder, and wherein one of said two links is pivotally connected to said lift arm means.

Claim 7

A material handling device as claimed in claim 5 wherein the other of said two links is pivotally connected to additional links, wherein one of said additional links is pivotally connected to said support and another of said additional links is pivotally connected to said bucket.

Claim 8

A material handling device comprising support means, lift arm means, a bucket pivotally carried by said lift arm means, first means pivotally connecting said lift arm means to said support means, first hydraulic motor means for raising and lowering said lift arm means, second means pivotally connecting said first hydraulic motor means to said lift arm means, third means pivotally connecting said first hydraulic motor means to said support means, second hydraulic motor means for pivoting said bucket relative to said lift arm means between maximum rollback and dump positions including a cylinder having a piston slidable therein and a piston rod extending out one end thereof pivotally connected to said lift arm means; said second hydraulic motor means arranged to apply maximum power during rollback of said bucket and maximum speed during dumping of said bucket, mechanical linkage means extending between said support means and said bucket for leveling said bucket when rolled back and for preventing rollback of said bucket past its level position when said lift arms are raised comprising a positioning link, a connecting link, a bucket control link, a leveling link, fourth means pivotally connecting one end of said positioning link and said connecting link to said cylinder, fifth means pivotally connecting the other end of said positioning link to said lift arm means, sixth means pivotally connecting one end of said leveling link to said support means, seventh means pivotally connecting one end of said bucket control link to said bucket and eighth and ninth means connecting the opposite ends of said leveling and bucket control links, respectively, to opposite ends of said connecting link.

Claim 9

A material handling device comprising support means, lift arm means, a bucket pivotally carried by said lift arm means, first means pivotally connecting said lift arm means to said support means, first hydraulic motor means for raising and lowering said lift arm means, second means pivotally connecting said first hydraulic motor means to said lift arm means, third means pivotally connecting said first hydraulic motor means to said support means, second hydraulic motor means for pivoting said bucket relative to said lift arm means between maximum rollback and dump positions including a cylinder having a piston slidable therein and a piston rod extending out one end thereof pivotally connected to said lift arm means; said second hydraulic motor means arranged to apply maximum power during rollback of said bucket and maximum speed during dumping of said bucket, mechanical linkage means extending between said support means and said bucket for leveling said bucket when rolled back and for preventing rollback of said bucket past its level position when said lift arms are raised comprising a positioning link, a connecting link, a bucket control link, a leveling link, fourth means pivotally connecting one end of said positioning link and said connecting link to said cylinder, fifth means pivotally connecting the other end of said positioning link to said lift arm means, sixth means pivotally connecting one end of said leveling link to said support means, seventh means pivotally connecting one end of said bucket control link to said bucket and eighth and ninth means connecting the opposite ends of said leveling and bucket control links, respectively, to opposite ends of said connecting link.

Claim 10

A material handling device as claimed in claim 7 wherein said first means is located above said second means, said sixth means is located between said first and second means, said eighth means is disposed above said ninth means and said fourth means is disposed therebetween.

Claim 11

A mAterial handling device as claimed in claim 7 wherein said leveling link causes said connecting link to rotate about said fourth means to pivot said bucket towards dump position in response to the raising of said lift arm means.