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LAWN RAKE AND CROSS HEAD ASSEMBLY


U.S. PATENT 6,131,381

Issued: October 17, 2000



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ABSTRACT


A lawn rake (100) has a cross head assembly (130) attached to a handle (120). A truncated tee (150) mounted on the cross arm (145) of the cross head assembly (130) receives the handle (120). A plurality of tines (170) is carried by the cross arm (145). The cross arm (145) is tubular and has a plurality of pairs (162) of apertures (164). The apertures (164) are larger than the cross section of the tines (170). The tines (170) are inserted through, and loosely positioned by, the apertures (164). The plurality of tines (170) forms an array (160) that is generally coplanar. The array (160) may form an obtuse angle with respect to the handle (120). Embodiments of the rake include arrays of tines (170) configured to form alternating rows of tines or a curvilinear arrangement of tines. A looped bend (178) formed in the end of each tine (170) distal to the ground engaging tip (176), snaps around the cross arm (145) to pivotally mount each tine (170). The tines (170) are replaceable, and are mountable on and removable from the cross arm (145) by application of finger force. The tines (170) are releasable. During raking action, an impact load directed upwardly on a tip (176) may cause release of the looped bend (178) from the cross arm (145), thereby preventing breakage of the tine (170). The lawn rake (100) can be used in a push mode. The lawn rake (100) may be distributed as a kit of parts. Components of lawn rake (100) are preferably made from a thermoplastic material. In particular the thermoplastic material may be polyvinylchloride.


SUMMARY OF THE DISCLOSURE



The present invention is directed to a species of broom-style lawn rakes defined by a cross head assembly. The cross head assembly is attached to the end of a handle. The cross head assembly further includes a transverse cross arm and a plurality of tines. A truncated tee can be mounted on the tubular cross arm and connects the cross head assembly to the handle. The tines are individually replaceable. Each tine is a self-contained element that has a looped bend formed in the end of the tine opposite the ground engaging tip. The looped bend may form an arc segment of a circle. The tines are mounted onto the cross head be insertion through pairs of aligned apertures. The looped bends of the tines snap into place around the cross arm which retains them of the cross arm, with the apertures holding the tines loosely in place in side-by-side spaced alignment.

The plurality of tines so attached forms an array. The array may be substantially coplanar. The tips of the tines may be so arranged that tip spacing is uniform. Uniform tip spacing may require the medial tines, each adjacent one side of the truncated tee, to converge towards one another. The tines adjacent the two medial tines then must have closer spacing than the remainder of the tines in order to achieve uniform tip spacing.

For an array that is substantially coplanar, the pairs of apertures are colinearly aligned parallel to the axis of the cross arm. Pairs of apertures that are diametrically opposed may assume other configurations that result in two or more alternating rows of tines, or that result in arrays that are curvilinear.

The paired apertures in the cross head are oversized to permit insertion and removal of the tines by finger force and to loosely hold the tines in position on the cross arm. The tines are preferably made from a thermoplastic material to provide flexibility for raking action as well as the necessary flexibility to distend as they are inserted or removed through the paired apertures. The tines may have a circular cross section, as may the apertures. The cross arm and truncated tee may be made from the same class of materials as the tines. The plane of the array of the tines generally subtends an obtuse angle with respect to the handle, but embodiments may be coplanar with the handle. The tines, transverse cross arm, and truncated tee may all be made from the thermoplastic material, polyvinylchloride. In conjunction with a polyvinylchloride handle, the lawn rake may thus be made from one material except for fasteners. Embodiments may include tines that have a flat, rectangular cross section, and/or tines that are metallic, and/or a cross arm that is metallic.

The tines do not require fasteners, clips, or retainers to stay in place or maintain their general position during use of the lawn rake. The tines are, furthermore, releasable during raking action. The oversized apertures allow is freedom of movement of the tines, reducing the moment resistance of the connection of the tines to the cross arm. Thus, stresses in the tines are reduced, greatly minimizing the chance of tine breakage. In the course of raking action, a tine may be subjected to axially directed forces on the end such as might occur when a tine hits a rock when the rake is placed to commence raking action. The oversized apertures, together with the non-rigid, non-fixed, and non-frictional mounting of the looped bend on the cross arm, allow the looped bend to unsnap from engagement with the cross arm, releasing the tine without breaking. However, the tine can be prevented from shooting out of the cross arm. An obtuse angular bend in the tine proximate the ground engaging tip, may serve the purpose of preventing the tine from passing completely through the pair of apertures without application of at least one more force. Thus, the tines are removable, energy absorbing, and releasable.

Even though the tines have considerable lateral flexibility, when the tines are engaged with the ground in raking action, the tines all tend to deflect to the same extent in the same direction, at the same time. Alignment is maintained by the looped bend in each tine which wraps around the cross arm with freedom of movement both perpendicular and parallel to the cross arm. The freedom of movement allows the tines to better withstand loading conditions during the normal course of raking. At the same time, the shifting of the looped bends permits the tines to stay generally aligned in the direction of raking action. Tines that have a circular cross section, together with pivotal mounting of the tines on the cross arm, allow raking action that is laterally directed or arcuate in motion, or that has quick changes in direction, all while the lawn rake remains in contact with the ground.

When the tines are in contact with the ground and deflected during raking action, the back side of each tine is generally in contact with the back edge of its bottom circular aperture. When the tines are released from the ground, the oversized apertures allow the tines to spring forward so that the front of the tines snap against the front of the bottom circular apertures. This snapping action transmits more kinetic energy to the leaves and lawn debris than would occur if the tines merely unbend from their deflected raking position, without a freedom of movement at their mounting as allowed by the oversized apertures.

The tines retain all of the normal functions of gathering and collecting leaves and lawn debris that other rakes provide, in addition to the improvements noted above. The lawn rake embodies an additional, new method of operation by allowing the capability of pushing piles of accumulated leaves and lawn debris. When utilized in the push mode, the tines bend in a direction opposite to the direction in which the tines bend when the lawn rake is used in a conventional raking mode. This capability is inherent in the lawn rake embodiment having a cross head assembly subtending an appropriate obtuse angle with respect to the handle.

The entire rake can be disassembled so that it has the capability of being distributed as a disassembled kit of parts within a relatively compact shipping container such as a mailing tube.

It is understood that both the foregoing summary and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention, as claimed.

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