(Not Applicable)
(Not Applicable)
1. Field of the Invention
The present invention relates generally to the field of cement trucks and more particularly to a lift elevator for assisting an operator with lifting heavy items up to the mouth of a cement truck's mixing drum.
2. Description of the Related Art
Traditionally, in order to deposit additives into the mixing drum of a cement truck, it has been necessary for an individual to manually carry a bucket full of additive, commonly weighing over 50 pounds, up a ladder to a height of about 15 feet to dump the additive into the mouth of the mixing drum. It is well known that performing such a task can expose an individual to the risk of serious injury. For example, an individual may experience severe upper body strain or may fall from the ladder while attempting to carry the heavy bucket with one hand and climb the ladder with his or her other hand. Likewise, a bystander may be struck by a bucket that is accidentally dropped by the individual while attempting to perform the task.
In view of the foregoing, it would be advantageous to provide a means for assisting an individual with lifting a container of additive to the mouth of a cement truck's mixing drum that allows the individual to use both of his or her hands to climb the cement truck's ladder. It would further be advantageous to provide such a means that is integral with a cement truck. It would further be advantageous to provide such a means that takes up a minimal amount of space and that is generally unobtrusive when not in use.
In accordance with the present invention, there is provided a cement truck lift elevator for assisting an operator with lifting heavy items, such as containers filled with cement additives, to the mouth of a cement truck's mixing drum. The preferred lift elevator includes an elongated, tubular lift housing that is rigidly mounted to a cement truck. The lift housing has a guide slot formed in its wall that extends vertically from adjacent the surface upon which the cement truck sits to a point adjacent the mouth of the truck's mixing drum. A drive winch, which is preferably a 12 Volt electric winch, is mounted to the cement truck adjacent the lift housing. The drive winch is operatively connected to a steel lift cable that extends into the lift housing and engages a pair of transmission pulleys that redirect the lift cable downwardly to a cylindrical lift carriage. The lift carriage is axially rotatable and vertically moveable relative to the lift housing. A shelf member is connected to the lift carriage by a mounting arm that extends through the guide slot in the lift housing.
By operating the drive winch, such as with a conventional, wash-down-protected control pad, an operator can spool or unspool the lift cable to raise and lower the shelf member along the length of the lift housing between a “down” position, wherein the shelf member is adjacent the lower end of the lift housing, and an “up” position, wherein the shelf member is adjacent the upper end of the lift housing. As the shelf member is raised and lowered, the mounting arm travels vertically within the guide slot of the lift housing. Limit switches can be installed within the lift housing and operatively connected to the drive winch for causing the shelf member to automatically stop at the “up” and “down” positions.
A lower pivot notch is preferably formed in the lift housing adjacent the “down” position of the shelf member. The lower pivot notch extends perpendicularly from the guide slot for accepting the mounting arm and allowing the shelf member to be pivoted about the axis of the lift carriage between an operating position, wherein the mounting arm is in the guide slot, and a stowed position, wherein the mounting arm is in the lower pivot notch. In the stowed position, the shelf member is nearer the body of the cement truck and is therefore less obtrusive than when the shelf member is in the operating position. The shelf member is preferably securely fastened in the stowed position when the lift elevator is not in use, such as when the cement truck is in transit.
An upper pivot notch that is similar to the lower pivot notch is preferably formed in the lift housing adjacent the “up” position of the shelf member. Like the lower pivot notch, the upper pivot notch allows the shelf member to be rotated about the axis of the lift carriage to a dump position that is nearer the body of the cement truck than the operating position. An operator is thereby not required to move an item, such as a heavy bucket of color additive, very far from the shelf member to dump its contents into the mouth of the cement truck's mixing drum.
Typical use of the lift elevator involves an operator first rotating the shelf member from the stowed position to the operating position and placing an item to be lifted on top of the shelf member. The operator then manipulates the control pad of the drive winch to spool the lift cable, thereby hoisting the shelf member from the down position along the lift housing to the “up” position. Next, the operator climbs to the top of the cement truck's ladder and pivots the shelf member to the dump position, where the shelf member is preferably secured by a removable fastener. The operator then removes the bucket from the shelf member and dumps the contents of the bucket into the mouth of the mixing drum. The operator then replaces the bucket on the shelf member, rotates the shelf member back to the operating position, climbs down the ladder and uses the control pad to lower the shelf member to the “down” position. The shelf member can then be stowed or used again in the manner described above.
In describing the preferred embodiment of the invention which is illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific term so selected and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.
Referring to
Referring to
A narrow, elongated guide slot 24 is formed in the wall of the lift shaft 20. The guide slot 24 extends along the entire length of the lift shaft 20 and preferably measures about three-eighths of an inch wide. A first, lower pivot notch 26 is formed in the wall of lift shaft 20 about a foot from the bottom end of the lift shaft 20. The lower pivot notch 26 extends leftward (as shown in
Still referring to
The lift carriage 34 is positioned inside the lift shaft 20 in a substantially coaxial relationship therewith, with the radially outwardly-facing surfaces of the guide wheels 42 and 44 resting against the wall of the lift shaft 20. The lift carriage 34 can thus travel vertically along the interior of the lift shaft 20, with the guide wheels 42 and 44 engaging and riding along the interior of the lift shaft's wall. The guide wheels 42 and 44 do not prohibit significant rotation of the lift carriage 34 relative to the lift shaft 20, but, due to their single axis of rotation, do not promote such rotation. The guide wheels 42 and 44 instead promote smooth, longitudinal movement of the lift carriage 34 within the lift shaft 20, while still permitting rotation of the lift carriage 34 relative to the lift shaft 20 at certain points along the lift shaft's length, as described in greater detail below, provided a sufficient torque is applied to the lift carriage 34.
The transmission pulleys 36 and 38 are conventional fixed pulleys that are rigidly mounted to the interior of the transmission shaft 22 adjacent the ends of the horizontally oriented segment of the transmission shaft 22. The drive winch 14 is a conventional, 12V electric winch, similar to those commonly found on all terrain vehicles (ATVs), although it is contemplated that a similarly sized pneumatic or hydraulic winch can be substituted for the drive winch 14. For example, an industrial hoist can be substituted for the ATV winch. The lift cable 40, which is preferably formed of conventional steel cable, is operatively connected to the drive winch 14 in a conventional manner. The lift cable 40 extends from the drum of the drive winch 14 upwardly, into the transmission shaft 22, and traverses and operatively engages both of the transmission pulleys 36 and 38. The lift cable 40 is thereby redirected downwardly, into the lift shaft 20, and is connected to the lift carriage 34, preferably without contacting the sidewalls of the housing through which it passes. This configuration allows the lift carriage 34 to be raised and lowered through operation of the drive winch 14, as will be described in greater detail below.
Referring to
The mounting arm 47 of the conveyor platform 16 is formed of a segment of L-shaped (in section) steel angle measuring about 16 inches in length, although it is contemplated that the mounting arm 47 can alternatively be formed of various other types of elongated brackets, bars, or plates of similar size and strength. Importantly, the mounting arm 47 has a height that is less than the height of the pivot notches 26 and 28 in the lift shaft 20 (described above). The mounting arm 47 extends horizontally from a first end located below the shelf member 45, through the guide slot 24 of the lift shaft 20 (as best shown in
The floor 49 of the shelf member 45 is mounted to the mounting arm 47 with conventional removable fasteners for allowing the shelf member 45 to be conveniently removed and replaced as desired. For example, the shelf member 45 can be replaced by a similar shelf member if the original shelf member 45 becomes worn or damaged. Alternatively, the shelf member 45 can be replaced by other types of platforms, shelves, or containers of different sizes and shapes for better accommodating particular items that are to be placed thereon.
Referring to
Referring to
The vertical edges of the lift shaft's wall that define the guide slot 24 are relatively closely spaced to prevent significant horizontal movement of the mounting arm 47 along the majority of the lift shaft 20, thereby preventing significant axial rotation of the lift carriage 34 within the lift shaft 20. However, when the conveyor platform 16 is moved to the “down” position, the mounting arm 47 is horizontally aligned with the lower pivot notch 26 in the lift shaft 20 where the guide slot 24 is deliberately made very wide. The conveyor platform 16 and the lift carriage 34 can therefore be pivoted horizontally about the axis of the lift carriage 34 between a stowed position (shown in
In the stowed and dump positions, the conveyor platform 16 is positioned near the body of the cement truck 59 and is prevented from moving vertically by the horizontally-oriented edges of the pivot notches 26 and 28, respectively, which limit the vertical movement of the mounting arm 47. In the operating position, the mounting arm 47 is positioned in, and can move freely within, the guide slot 24, thereby allowing the conveyer platform 16 to be moved vertically along the lift shaft 20 between the “up” position and the “down” position.
Referring to
The electrical components of the preferred embodiment of the present invention are shown schematically in
Typical operation of the elevator 10 will now be described with reference to
Next, the operator depresses the UP button on the control pad 52 of the drive winch 14 to spool the lift cable 40, thereby hoisting the lift carriage 34, the conveyor platform 16 and the bucket 76 upwardly, along the lift shaft 20. The operator continues to elevate the conveyor platform 16 until it reaches the “up” position, with the mounting arm 47 horizontally aligned with the upper pivot notch 28 in the lift shaft 20. Next, the operator climbs to the top of the ladder 61 in a conventional manner. The operator then manually pivots the conveyor platform 16 to the dump position and connects the chain 72 to the conveyor platform 16 in the manner described above. Next, the operator removes the bucket 76 from the shelf member 45 and dumps the contents of the bucket 76 into the mouth of the mixing drum. The operator then replaces the bucket 76 on the shelf member 45, straps the bucket 76 down, disconnects the chain 72 from the conveyor platform 16, and rotates the conveyor platform 16 to the operating position. Finally, the operator climbs down the ladder 61 and depresses the DOWN button on the control pad 52 to lower the conveyor platform 16 to the “down” position. The elevator 10 can then be used again in the manner described above, or the conveyor platform 16 can be secured in the stowed position so that it is out of the way.
Referring to
Although the apparatus shown and described herein is preferred, other structures are contemplated for accomplishing the same or similar purposes. For example, it is contemplated that, instead of a driven cable, a different drive linkage, such as a screw drive, can be used. In this alternative, a threaded shaft in the pipe is drivingly linked to a prime mover, such as an electric, pneumatic or hydraulic motor, at the lower end to drive the lift carriage vertically by the shaft rotating about its central axis within a threaded bore mounted to the lift carriage. Alternatively, although it is preferred for the conveyor platform to lift only the container of material to be added to the mixture of concrete and the person climbs a ladder on the truck, it is contemplated that a conveyor platform can be constructed to lift the person and the container of material. In this embodiment, the drive mechanism preferably extends lower than on the preferred embodiment so the lift platform can be accessed from ground level.
This detailed description in connection with the drawings is intended principally as a description of the presently preferred embodiments of the invention, and is not intended to represent the only form in which the present invention may be constructed or utilized. The description sets forth the designs, functions, means, and methods of implementing the invention in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and features may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention and that various modifications may be adopted without departing from the invention or scope of the following claims.
This application is a continuation-in-part of U.S. patent application Ser. No. 11/895,916 filed Aug. 28, 2007, which is incorporated herein by reference.
Number | Date | Country | |
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Parent | 11895916 | Aug 2007 | US |
Child | 12774098 | US |