Adjustable hand truck

Claim 2

In a tiltable hand truck having a pair of main wheels rotating on an axle, a support platform, and at least two upwardly extending frame rails, the improvement which comprises: a. a generally V-shaped secondary frame means having its bifurcated ends pivotally mounted about an axis of rotation parallel to the axle supporting said main wheels, said secondary frame being substantially parallel to the ground when said secondary frame is in use and with said bifurcated ends lying inwardly of said main wheels, b. at least one auxiliary wheel operatively connected to said secondary frame, c. an upwardly extending support rail mounted on said truck parallel to said upwardly extending frame rails, d. adjustable gripping means for reciprocating along and fixably gripping said support rail at a plurality of points along said support rail, e. linkage means linking said adjustable gripping means to said secondary frame at the junction of said bifurcated ends to securely fix said secondary frame means at a specific angle to said parallel frame rails at a specific point along said support rail, said angle being varied as the gripping means reciprocates along said support rail.

Claim 3

A tiltable hand truck as claimed in claim 1 wherein said adjustable gripping means further comprises a. a housing extending around said support rail, b. at least one locking ring having an aperture of the same configuration and slightly larger dimension than the cross-section of said support rail, said at least one locking rinG being pivotally attached to said housing, said ring being perpendicular to said support rail when said gripping means is reciprocating along said support rail, and c. resilient means mounted between said housing and gripping means to pivot said at least one locking ring about a pivot point and cause the ring to wedge securely between said support rail and said housing when said gripping means is in its fixed position.

Claim 4

The apparatus of claim 2 wherein said adjustable locking means comprises two said locking rings which are superimposed one on top the other, said housing defining a pivot for said locking rings, and first and second spring means each urging a respective one of said rings into a locking position relative to said support rail.

Claim 5

A tiltable hand truck as claimed in claim 1 wherein said auxiliary wheel comprises a castor wheel which is free to rotate in any direction.

Claim 6

A tiltable hand truck as claimed in claim 4 wherein said castor wheel is mounted on a third frame means, said third frame means reciprocating relative to said secondary frame means to adjust the distance between said auxiliary wheel and said pair of wheels mounted on said hand truck.

Claim 7

A tiltable hand truck as claimed in claim 1 wherein said support rail defines a plurality of notches along its longitudinal dimension, and said gripping means defines a pivotable locking means to engage said notches and lock said gripping means in place at each notch location.

Claim 8

A tiltable hand truck as claimed in claim 1 which further comprises resilient means for urging said secondary frame means towards said parallel frame rails, said movement being resisted by said linkage means when said secondary frame means is in use.

Claim 9

A tiltable hand truck as claimed in claim 1 wherein said upwardly extending support rail is located midway between said upwardly extending frame rails.

Claim 10

In a tiltable hand truck having a pair of wheels, a support platform, and at least two upwardly extending frame rails, the improvement which comprises a. a secondary frame means mounted on said truck to pivot about the axis of rotation between said wheels and said upwardly extending frame rails, said secondary frame being substantially parallel to the ground when said secondary frame is in use, b. an upwardly extending support rail mounted on said truck parallel to said upwardly extending frame rails, c. adjustable gripping means for reciprocating along and fixably gripping said support rail at a plurality of points along said support rail, d. linkage means linking said adjustable gripping means to said secondary frame to securely fix said secondary frame means at a specific angle to said parallel frame rails at a specific point along said support rail, said angle being varied as the gripping means reciprocates along said support rail, and e. a third frame means which reciprocates relative to said secondary frame means and an auxiliary castor which is supported on said third frame means whereby the distance between said auxiliary castor and said wheels may be varied.

Claim 11

In a tiltable hand truck having a pair of wheels, a support platform, and at least two upwardly extending frame rails, the improvement which comprises a. a secondary frame means mounted on said truck to pivot about the axis of rotation between said wheels and said upwardly extending frame rails, said secondary frame being substantially parallel to the ground when said secondary frame is in use, b. an upwardly extending support rail mounted on said truck parallel to said upwardly extending frame rails, c. adjustable gripping means for reciprocating along and fixably gripping said support rail at a plurality of points along said support rail, d. linkage means linking said adjustable gripping means to said secondary frame to securely fix said secondary frame means at a specific angle to said parallel frame rails at a specific point along said support rail, said angle being varied as the gripping means reciprocates along said support rail, and e. a third frame means which reciprocates relative to said secondary frame means and an auxiliary castor which is supported on said third frame means whereby the distance between said auxiliary castor and said wheels may be varied.