Handling: hand and hoist-line implements – Hand forks and shovels – Attachments
Reexamination Certificate
2001-03-20
2002-04-16
Kramer, Dean J. (Department: 3652)
Handling: hand and hoist-line implements
Hand forks and shovels
Attachments
C254S131500
Reexamination Certificate
active
06371542
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to load lifting accessories, and particularly relates to load lifting accessories which are used with manual shovels for handling heavy loads such as snow, sand and soil. The load lifting accessory of the present invention is designed in such a manner that when it is in use with the manual shovel, the user is relieved of severe vertebral and back muscle strains which are associated with shovelling heavy loads. Furthermore, the load lifting accessory of the present invention is such that it may be easily removably attached to the shaft of the manual shovel so as to provide the user the flexibility to transfer the load lifting accessory to the shaft of any conventional manual shovel.
BACKGROUND OF THE INVENTION
Shovelling heavy loads such as snow, sand and soil has been one of the leading causes of back strain injuries. In fact, gardeners and other individuals who are required to shovel heavy loads on the job are reported to be the most susceptible victims to such injuries. For many others, shovelling snow throughout the winter months often results in vertebral and muscle strains.
Indeed, shovelling snow has been compared to weightlifting by some kinesiologists. It requires a lot of exertion and it is a multi-joint movement exercise. A variety of muscles are used during the activity, both large and small muscles-large muscles such as leg muscles and small muscles such as those found in the region of the lower back. The small muscles are particularly prone to strain injuries because these small muscle groups are not used as often as the large leg muscles. For those persons who are naturally weak or for those who don't usually get much exercise, shovelling heavy loads may be a health risk.
A conventional manual shovel is, in fact, not a very efficient tool to lift heavy loads since a relatively large effort needs to be exerted by the user to overcome the resistance of each load. Generally, the user grips the shaft of the shovel with one hand at a point which is relatively low along the length of the shaft, and uses his other hand to effectively lever the shaft about that point. A conventional manual shovel is a typical example of a third class lever. The effort is applied by the one hand which is positioned near the load, and the fulcrum is situated at the other hand which is distal from the blade of the shovel. Physiologically, the spinal vertebrae and the associated back muscles act as a cantilever to resist the weight of the load in each shovelling motion. Since the back of the user is typically bent forward to load and lift the shovel, the whole weight of his torso, shoulders, arms and head adds additional strain to his back. The spine is stressed in compression and the muscles in tension to resist the bending of the back, and thus often leads to fatigue, soreness, and injuries.
Although powered shovels may be employed as an alternative, they are considered to be too expensive for many consumers. Furthermore, most powered shovels are difficult for storage and are not portable. In areas where access is limited, shovelling with a powered shovel may also pose difficulties since most powered shovels are bulky and heavy to manoeuver.
The present inventor herein has provided a load lifting accessory which is adapted to be affixed to the shaft of a conventional manual shovel. The load lifting accessory of the present invention is simple, economical, portable, lightweight and compact. In addition, the load lifting accessory of the present invention is such that it may be easily removably attached to the shaft of the manual shovel so as to provide the user the flexibility to transfer the load lifting accessory to the shaft of any conventional manual shovel. Most importantly, the load lifting accessory of the present invention is designed in such a manner that when it is in use with the manual shovel, the user is relieved of severe vertebral and back muscle strains which are associated with shovelling heavy loads.
The load lifting accessory of the present invention generally comprises a bracket, a support arm and a retractor arm. The bracket is adapted to embrace the underside of the shaft of the shovel when the shovel is oriented in a normal shovelling position in such a manner that the region of the midpoint of the underside of the shaft of the shovel is rested against the inner surface of the bracket. The support arm is attached to the outer surface of the bracket by attachment means which permits pivotal movement of the support arm. When the shovel is in a non-operative position, the support arm is contiguous to the outer surface of the bracket. However, when the shovel is in an operative position, the support arm extends substantially vertically downwardly from the bracket to the ground.
When the load lifting accessory of the present invention is affixed to the shaft of the shovel, the conventional shovel becomes a first class lever, thus making the accessorized conventional shovel substantially more effective in overcoming large resistance since a relatively small effort is required for the operation of a first class lever. Here, the support arm of the load lifting accessory of the present invention operates as the fulcrum while the effort is applied by both hands of the user. Normally, lifting forces are applied by the user to the shaft of the conventional shovel having no load lifting accessory. However, with the implementation of the load lifting accessory to the conventional shovel, lifting forces are no longer required. Instead, the user needs only to apply downward forces to the shaft of the shovel since the support arm of the load lifting accessory provides the necessary upward lifting forces. To that end, the user may easily shovel heavy loads without bending his back, thus greatly reducing the usual spinal and back muscle strains and stresses.
DESCRIPTION OF THE PRIOR ART
Several prior art patents are noted, which relate particularly to shovelling tools and the like utilizing fulcrum type aids. They include the following:
BRUNO U.S. Pat. No. 4,130,953 issued Dec. 26, 1978;
KRUG U.S. Pat. No. 5,863,084 issued Jan. 26, 1999;
YANG U.S. Pat. No. 4,537,433 issued Aug. 27, 1985;
VROEGINDEWEY U.S. Pat. No. 5,669,651 issued Sep. 23, 1997;
LIGHTHIZER U.S. Pat. No. 4,722,512 issued Feb. 2, 1988;
PRATT U.S. Pat. No. 3,119,596 issued Jan. 28, 1964; and
CONANT U.S. Pat. No. 3,035,816 issued May 22, 1962.
Several other patents which relate more to the load lifting accessory, include the following:
EVERTSEN U.S. Pat. No. 4,881,332 issued Nov. 21, 1989 teaches an elongate, ground contacting member which is pivotally attached to an intermediate point along the handle of the shovel or similar tools. The elongate, ground contacting member has attachment means which permits rotation of the ground contacting member about its own axis. When the shovel is loaded, it is raised to the hip level of the user by drawing back and lowering the end of the handle opposite the shovel head while the ground contacting member acts as a fulcrum between the load and the user's applied force. The shovel head is then permitted to move sideways to deposit the load where desired. There are no means to stabilize the uncontrolled swinging of the elongate, ground contacting member when it is extended to the ground, and furthermore the device taught in this patent is not readily detachable from the primary tool.
In U.S. Pat. No. 4,198,090 issued Apr. 15, 1980 to GUTMAN, the inventor has provided a shovel which utilizes an adjustable type fulcrum member in combination with an adjustable hand gripping member for purposes of easing the shovelling of a load. The adjustable lever mechanism is releasably secured and movably displaceable in a direction substantially normal to the shaft of the shovel so as to provide an adjustable height above a base surface when the blade of the shovel is in contact with the base surface. The adjustable grip mechanism is releasably secured and movably displaceable with respect to the shaft and extends above such a shaft so as to provi
(Marks & Clerk)
Kramer Dean J.
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