Patent Application
20070261590
1. Field of the Invention
The present invention relates in general to a trolley wheel and, more particularly, to an improved trolley wheel having improved, superior heat resistant, wear and anti-contamination characteristics.
2. Description of the Prior Art
Animal carcasses are transported in a meatpacking plant typically through the use of a trolley system. A carcass or container of meat is typically secured to a wheel by a strap or other connection means to form a trolley. The trolleys move along a track to transport the meat from place to place. Each trolley typically includes a wheel having a recessed rolling surface which rides along the track system, and a pair of perimeter flanges to prevent the wheel from “jumping the track.” A meatpacking operation may employ hundreds or thousands of such trolleys.
Prior art trolleys are typically constructed of iron, or similarly soft material, so as not to cause excessive wear on the more expensive track system. The wheels are typically provided with brass or other type of bushing to allow the wheels to turn upon an axle. While the iron construction of the wheels does reduce the amount of wear on the track, iron tends to rust. Over time, this rust begins to flake off the wheel. If rust flakes off the wheel and onto the animal carcass hanging below, contamination is a significant concern. An additional drawback associated with prior art wheels is the difficulty in cleaning such wheels.
To clean the wheels and remove rust flakes, the entire trolley is typically washed in hot caustic. The caustic aids in removing rust flakes, while the temperature of the caustic, typically 180 degrees, kills bacteria on the wheel. Heat also serves to aid in the drying of the trolley when the trolley exits the caustic. A light coating of oil is applied to prior art trolleys to reduce oxidation and rust. After the trolleys exit the hot caustic, the oil cannot be applied until the trolley is dry. Although the heat of the trolley exiting the caustic agent dries the trolley very quickly, the freshly clean metal is exposed to the atmosphere for a short time before the oil is applied. During this short period of time, oxygen in the atmosphere oxidizes the trolley to form a thin coat of rust over the trolley. While most of this rust is removed during the next cleaning cycle, the constant rusting and rust removal subjects the trolley to premature wear.
Still another downside associated with the prior art is the likelihood of contamination as the light coating of oil slides down the trolley and drips down to contaminate the animal carcass. Another drawback associated with the prior art is the short lifespan of the trolley wheel. The trolley wheel is constructed of iron, is continually moved over a steel or otherwise hard surface, and is constantly worn down. The typical lifespan of a trolley wheel is short, averaging a year or less, depending on the amount and severity of use.
Tn addition to the wear associated with typical trolley wheels, in a “smokehouse” or other curing facility, trolleys are often used to transport containers of meat weighing five hundred to fifteen hundred kilograms or more per load. The trolleys typically enter an oven where they are subjected to temperatures of one-hundred eighty to two hundred degrees for a period of six to twelve hours. After the curing, the trolleys are typically subjected to a blast chill, which may or may not incorporate the application of chilled brine. This heating, cooling and application of brine works to wear the trolleys even more than the trolleys in a typical meatpacking operation.
These conditions are especially aggressive toward the bearings or other materials provided within the trolley to facilitate movement. For a sealed bearing system, the temperatures are so high for so long, the grease or other lubricant typically boils out of the trolley. For open bearing situations, the grease or lubricant typically leaves the trolley to contaminate the meat very quickly, and application of grease is required after every cure. While the bearings may be provided with oil, grease or other lubricant to facilitate rotation, the curing process often removes the lubricant which may drip down onto and contaminate the meat under the trolley. In situations where the bearings are not lubricated, the aggressive conditions often cause premature wearing on the bearings, causing the trolley to “slide” rather than rotate, thereby drastically decreasing the lifespan of the trolley.
The drawbacks associated with the prior art noted hereinabove are substantially eliminated by the present invention.
The present invention provides an improved trolley wheel assembly having a wheel provided around a plurality of spindles which, in turn, are provided around a hub. An axle is provided through the hub and retainers are provided on either side of the wheel to prevent the trolley from becoming dislodged from the rail system. Preferably, the wheel is provided with a highly abrasion-resistant, heat-resistant plastic and the interior is constructed of steel. The plurality of spindles are preferably constructed of a highly abrasion-resistant, heat-resistant plastic, while the hub is typically constructed of stainless steel. The axle and retainers are also preferably constructed of stainless steel. In the preferred embodiment, the perimeter of the wheel is grooved to provide more contact area with the rail, which is curved to provide mating engagement with the perimeter of the wheel.
With reference to the drawings, a trolley is indicated generally as (10) in
As shown in
As shown in
While any suitable number of bearings may be used, in the preferred embodiment, the number of bearings is preferably greater than three and less than twenty, more preferably greater than five and less than fifteen, and most preferably eleven. While in the preferred embodiment the spindles (46) are cylindrical in shape, the spindles may be of any suitable shape, including, but not limited to, an hourglass shape, a football shape, spherical or rounded cylindrical shape. Additionally, spindles (46) of different sizes, shapes and materials may be used together.
As shown in
Provided around the hub (50) is a pair of thrust washers (56) and (58). The thrust washers (56) and (58) are preferably constructed of nylon but may be constructed of any suitable material known in the art. As shown in
When the wheel assembly (12) is assembled, four securement pins (60) are provided for suitable insertion into the securement holes (62) provided in the endplates (26) and (28). The securement pins (60) may be secured within the securement holes (62) by deforming the ends of the securement pins (60), or by riveting, bolting, welding or otherwise securing the securement pins (62) by any means known in the art.
As shown in
Although the wheel assembly (12) of the present invention can be constructed of any desired dimensions and configurations, in the preferred embodiment the tire (30) is preferably 0.625 inches wide, the endplates (26) and (28) are preferably 0.190 inches wide, and the thrust washers (56) and (58) are 0.260 inches wide. The hub (50) is preferably 1.530 inches wide, while the ring (40) and spindles (46) are preferably 1.010 inches wide. The hub (50) is preferably provided with an inner race (44) diameter of 0.630 inches and an outer race (42) diameter of 1.0 inch. The spindles (46) are preferably 0.375 inches in diameter and the ring (40) is preferably provided with an inner race (44) diameter of 1.786 inches and an outer race (42) diameter of 2.000 inches. The tire (30) is preferably 3.75 inches in diameter at its widest point.
Prior art trolleys are typically cleaned with a hot caustic solution to remove any flaking rust. By constructing the wheel assembly (12) out of substantially non-reactive materials, rusting is substantially eliminated. Accordingly, the wheel assembly (12) of the present invention can be cleaned with a non-caustic, antibacterial detergent. Additionally, since the spindles (46) are non-metallic there is no need to oil or otherwise lubricate the spindles (46) after cleaning, and are resistant to freezing that typically occurs with prior art brine chilling processes. The novel construction of the wheel assembly (12) also eliminates potential carcass contamination from falling rust and oil.
Although the trolley (10) can be retrofitted into existing plants, preferably the trolley system (80), which includes the trolley (10) and a curved, stainless steel track (36). Alternatively, the system (80) can be retrofit into an existing plant by constructing the wheel assembly (12) with a tire (30) without a radius (32) and running the trolley (10) on the prior art track.
Although the invention has been described with respect to a preferred embodiment thereof, it is to be understood that it is not to be so limited, since changes and modifications can be made therein which are within the full, intended scope of this invention as defined by the appended claims. For example, it is anticipated that the wheel assembly (12) may be constructed of any material suitable to withstand a load greater than one thousand pounds and, more preferably, a load greater than two thousand pounds, and to withstand temperatures between 180 degrees and 200 degrees Fahrenheit for in excess of six hours, and subsequent quick chilling processes.
