Tow truck

Claim 2

In a combination truck, the improvement comprising, in combination: a frame; a horizontal bed supported on the frame; the frame including means defining a longitudinally extending well below the bed; a boom disposed longitudinally in the truck and being pivoted at its forward end to the frame below the bed, the rearward end of the boom being adapted to be pivoted about the pivot between a lowered position within the well and a raised position; scissors jack linkage means mounted to the frame at a location between the pivot and the rearward location of the rear axle of the truck for raising and lowering the boom, the scissors jack linkage means being further constructed and arranged to receive a downwardly directed load applied to the boom and to direct the load to the frame along a direction which is forward of the rear axle of the truck; the scissors jack linkage means further comprising: upper linkage means pivoted at its upper end to said boom; lower linkage means pivoted at its lower end to said frame; the free ends of said upper and lower linkage means being pivoted to each other at a common pivot, said common pivot being disposed rearwardly of said upper pivots; and means mounted to the frame of the truck for operating said linkage means and comprising a hydraulic cylinder pivoted at its rearward end to the frame of the vehicle and having a substantially forwardly extending piston rod, said piston rod being pivoted to said lower linkage means at a location within the angle defined between said common pivot and said upper and lower pivots.

Claim 3

A truck as defined in claim 1 further comprising: said hydraulic cylinder and scissors jack arrangement being so constructed so that the axis of the hydraulic cylinder does not exceed an angle of 45* with the horizontal through its operating range.

Claim 4

A truck as defined in claim 1 further comprising: said boom being of telescopically extendible construction and including: a substantially tubular boom member pivoted at its forward end to the frame within the well; a slidable boom extension within said tubular member and being slidable axially and inwardly and outwardly thereof; and means mounted within said boom for effecting said movement of said boom extension.

Claim 5

A truck as defined in claim 3 wherein said means for effecting extension and retraction of the boom extension comprises: an hydraulic cylinder mOunted within the forward end of the tubular boom member, said hydraulic cylinder having a rearwardly extending piston rod, said boom extension being hollowed to receive said piston rod; and means connecting the end of the piston rod to the extension member.

Claim 6

In a combination truck, the improvement comprising, in combination: a frame; a horizontal bed supported on the frame; said frame including means defining a longitudinally extending well below the bed; a boom disposed longitudinally in the truck and being pivoted at its forward end to the frame below the bed, the rearward end of the boom being adapted to be pivoted about the pivot between a lowered position within the well and a raised configuration; scissors jack linkage means mounted to the frame within the well and at a location between the pivot and the rearward location of the rear axle of the truck, said scissors jack linkage means being connected to said boom for raising and lowering said boom; said scissors jack linkage means being constructed and arranged to receive a downwardly directed load applied to said boom and to direct said load to said frame along a direction which is forward of the rear axle of said truck; means mounted to the frame of the truck and being operatively connected to said scissors jack linkage means for raising and lowering the boom; the scissors jack means comprising upper linkage means pivoted at its upper end to said boom and lower linkage means pivoted at its lower end to said frame, the free ends of said upper and lower linkage means being pivoted to each other at a common pivot, said common pivot being disposed rearwardly of said upper and lower pivots; said means for operating said linkage means comprising an hydraulic cylinder pivoted at its rearward end to the frame of the truck and having a substantially forwardly extending piston rod, said piston rod being pivoted to said lower linkage means at a location within the angle defined between said common pivot and said upper and lower pivots; said boom being of telescopically extendable construction and including a substantially tubular boom member pivoted at its forward end to the frame within the well, a slidable boom extension within the tubular member and being slidable axially and inwardly and outwardly thereof and means mounted within said boom for effecting said movement of said boom extension; means at the rear lower end of the truck frame for attachment of a tow bar; means enabling the boom extension to be extended outwardly and rearwardly slightly while the boom is in a substantially lowered position; and means enabling direct attachment of a tow strap arrangement to the rearwardly projecting end of the boom extension whereby the tow straps may be retained substantially firmly in a downwardly and rearwardly inclined attitude to enable the straps to act in wedge-like manner when the tow truck is backed up.

Claim 7

In a combination truck, the improvement comprising, in combination: a frame; a horizontal bed supported on the frame; said frame including means defining a longitudinally extending well below the bed; a boom disposed longitudinally in the truck and being pivoted at its forward end to the frame below the bed, the rearward end of the boom being adapted to be pivoted about the pivot between a lowered position within the well and a raised configuration; scissors jack linkage means mounted to the frame within the well and at a location between the pivot and the rearward location of the rear axle of the truck, said scissors jack linkage means being connected to said boom for raising and lowering said boom; said scissors jack linkage means being constructed and arranged to receive a downwardly directed load applied to said boom and to direct said load to said frame along a direction which is forward of the rear axle of said truck; means mounted to the frame of the truck and being operatively connected to said scissors jack linkage means for raising and lowering the boom; the scissors jack means comprising upper linkage means pivoted at its upper end to said boom and lower linkage means pivoted at its lower end to said frame, the free ends of said upper and lower linkage means being pivoted to each other at a common pivot, said common pivot being disposed rearwardly of said upper and lower pivots; said means for operating said linkage means comprising an hydraulic cylinder pivoted at its rearward end to the frame of the truck and having a substantially forwardly extending piston rod, said piston rod being pivoted to said lower linkage means at a location within the angle defined between said common pivot and said upper and lower pivots; said boom being of telescopically extendable construction and including a substantially tubular boom member pivoted at its forward end to the frame within the well, a slidable boom extension within the tubular member and being slidable axially and inwardly and outwardly thereof and means mounted within said boom for effecting said movement of said boom extension; means at the rear lower end of the truck frame for attachment of a tow bar; means enabling the boom extension to be extended outwardly and rearwardly slightly while the boom is in a substantially lowered position; and means enabling direct attachment of a tow strap arrangement to the rearwardly projecting end of the boom extension whereby the tow straps may be retained substantially firmly in a downwardly and rearwardly inclined attitude to enable the straps to act in wedge-like manner when the tow truck is backed up.

Claim 8

A truck as defined in claim 5 wherein the means enabling the boom to be extended rearwardly while in a substantially lowered position comprises: said truck including a rear panel which enclose the rear end of said well, said panel having a cutout in alignment with the boom, when the boom is in a lowered position, said boom being extendible rearwardly through said cutout.

Claim 9

A truck as defined in claim 1 further comprising: said bed including a portion covering said well, said portion being separable from the remaining portions of said bed and being secured to said boom for pivotal movement therewith.

Claim 10

A truck as defined in claim 1 further comprising: means defining an opening at the rear end of the well to enable the outer end of the boom to be extended beyond the rear end of the truck at least when the boom is lowered fully.