TEMPERATURE INDICATOR FOR A CRANKSHAFT FILLED WITH A SEMI-FLUID SYNTHETIC GREASE DESCRIPTION OF THE INVENTION This invention is generally directed to a novel temperature indicator to provide a visual indication to an operator when a vehicle crankshaft such as a trailer crankshaft, filled with a semi-fluid synthetic grease to lubricate the wheel bearings has reached an unsafe temperature. More particularly, a form of the present invention is directed to a novel temperature indicator that can be retrofitted to crankshafts of existing vehicles without modification of the crankshaft design. Conventional bucket trucks with bucket / bearing designs have moved towards using a semi-fluid synthetic grease lubricant to lubricate the wheel bearings instead of gear oil as was commonly used in old bucket / bearing designs. trailer. Synthetic semi-fluid grease is more advantageous because it is not as sensitive to a less perfect wheel seal, and therefore it is less likely to leak than with a crankcase filled with oil. When the leakage occurs with a crankcase filled with oil, the oil spreads or sprinkles around the crankshaft, saturating everything in that area. This can result in a fire from the hot brake pads and the drums that are covered with oil if the seal fails. When the leakage is presented with a crankcase filled with semi-fluid synthetic grease, because the semi-fluid synthetic fat is more solid than the oil, the semi-fluid synthetic grease does not spread or spray around the crankshaft like oil. Synthetic semi-fluid grease simply pushes beyond the seal and either falls cleanly or remains around the immediate area, thus preventing fires. An advantage of using a crankshaft filled with oil is that such buckets are easy to monitor with a window on the bucket cover that has a filling line. If the user finds that the oil is low (this is below the filling line), a plug is simply pulled over the hub cup and oil is added until the level of the filling line is reached. With a crankcase filled with semi-fluid synthetic grease, however, the semi-fluid synthetic grease does not flow through the bearings, but tends to remain in the grease chamber in the bucket even when the wheel is stopped. This occurs especially in cold weather since synthetic semi-fluid grease is used. At low temperatures, the viscosity of the semi-fluid synthetic grease is heavy as a grease, but at higher temperatures, the semi-fluid synthetic grease begins to flow like a heavy liquid.
. X Due to this characteristic of the semi-fluid synthetic grease, a windowless bucket cup is used to prevent the mechanic from mistakenly thinking that the bucket is low in oil since the oil level is not shown in the window. Because the window used with the oil does not work with a bucket filled with semi-fluid synthetic grease, usually a simple metal or solid plastic cup is used. The problem that results is that the mechanic can not monitor the crankshaft to determine if there is an adequate amount of lubricant. It is well known that if a wheel bearing is operated for a long time without proper lubrication, the bearing will heat up markedly and cause the hub to also heat up as the bearings press on the wheel / hub. This can result in a catastrophic bearing failure if this condition is left undetected. The present invention features a novel temperature indicator to provide a visual indication to an operator of when a vehicle crankshaft, such as a towing crankshaft, filled with a semi-fluid synthetic grease for the lubrication of the wheel bearings has reached a dangerous temperature. An existing form of the temperature indicator according to the present invention can easily be adjusted in existing trucks, without modification of the trailer. Other features and advantages of the present invention will be apparent upon reading the appended specification, in combination with the study of the drawings. A general object of the present invention is to provide a novel temperature indicator to provide a visual indication to an operator of when the crankshaft of a vehicle such as a towing crankshaft, filled with a semi-fluid synthetic grease for the lubrication of the bearings. wheel has reached a dangerous temperature. An object of the present invention is to provide a novel temperature indicator that can be retrofitted to the crankshafts of existing vehicles without modification of the crankshaft design. Another object of the present invention is to provide a novel temperature test that can be used in combination with a filling hole in a vehicle crankshaft. Briefly, and in accordance with the foregoing, the present invention features a novel temperature indicator to provide a visual indication to an operator of a vehicle crankshaft, such as the crankshaft of a trailer, filled with a semi-fluid synthetic grease for lubrication the wheel bearings where it has reached a dangerous temperature.
In one embodiment the temperature test is provided through a wheel hub of a conventional wheel mounting apparatus. The wheel mounting apparatus includes a crankshaft with a plurality of wheel bearings, and a chamber provided between the wheel hub and the crankshaft to accommodate the semi-fluid synthetic grease to lubricate the wheel bearings. The temperature test consists of an indicator pin mounted in a housing. When the bearings reach a dangerous temperature, the indicator pin comes out of the housing and the wheel hub to alert the user that a dangerous temperature has been reached in the bearings. In another embodiment and in the preferred embodiment, a temperature test is provided in one of the hub cup bolts or fastening members of a conventional wheel mounting apparatus that is used to mount a hub cup to the hub of the wheel. The temperature test consists of an indicator pin that is mounted in a housing. When the crankshaft reaches a dangerous temperature, the indicator pin comes out from the housing and from the hub cup to warn the user that a dangerous temperature has been reached in the crankshaft. BRIEF DESCRIPTION OF THE DRAWINGS The organization and manner of the structure and operation of the invention, together with other objects and advantages thereof, can be better understood with reference to the following description, made in connection with the accompanying drawings, wherein the numbers reference • similar identify the similar elements in which: Figure 1 is a cross-sectional view of a wheel mounting apparatus and a crankshaft having a novel temperature attached thereto incorporating the characteristics of a first embodiment of the invention that temperature test is in a first position that indicates to the user that the crankshaft is at a safe temperature; Figure 2 is an enlarged view of Figure 1 showing a portion thereof; Figure 3 is an enlarged cross-sectional view of a portion of the wheel mounting apparatus of Figure 1 having the temperature test attached to it, such a temperature test being in a second position indicating to the user that the bearings have reached a dangerous temperature; Figure 4 is a cross-sectional view of a wheel mounting apparatus and a crankshaft having a novel temperature indicator attached thereto, incorporating the features of a second embodiment of the invention, such as a temperature indicator in a first position indicating to the user that the crankshaft is at a safe temperature;
Figure 5 is an exploded view of the temperature indicator of Figure 4 which is formed of a temperature test and a hub cup bolt or fastener member shown in a cross section; Figure 6 is an enlarged view of Figure 4 showing a portion thereof; and Figure 7 is an enlarged cross-sectional view of a portion of the wheel mounting apparatus of Figure 4 having the temperature test attached to it, such a temperature test being in a second position indicating to the user that the crankshaft is at a dangerous temperature. Although the invention may be susceptible to the embodiment in different ways, it is shown in the drawings and a specific embodiment will be described in detail with the understanding that the present disclosure is to be considered as a non-limiting example of the principles of the invention, and that it is not intended to limit the invention to what is illustrated and described herein. The present invention provides a novel temperature indicator 20, 120, for an assembly using bearings lubricated with semi-fluid synthetic grease 48, such as a transmitting band assembly or a vehicle, for example a trailer, to visually indicate a user when a dangerous temperature has been reached by the bearings 48 during operation. As shown in the drawings, the temperature indicator 20, 120 is provided on a wheel mounting apparatus 24 of a trailer. It is to be understood that the present invention can use a variety of mechanical assemblies, as long as the assembly includes bearings between two movable components to allow one component to rotate with respect to the other component. A first embodiment of the invention is shown in Figures 1-3. A second embodiment of the invention is shown in Figures 4-7. Each is shown in a wheel mounting apparatus 24. The wheel mounting apparatus 24 is used to mount a wheel (not shown) in the vehicle. The wheel mounting apparatus 24 generally includes the crankshaft 22, a wheel hub assembly 26 and a brake assembly 28. The crankshaft 22 is fixedly mounted on the body of the vehicle by a suitable means and is formed of a hollow tube 30. having ends (only one is shown) having a hollow spindle 32 attached thereto by means of, for example, a weld 34. The spindle 32 is a hollow tapered member having a threaded end 36. The hollow tube 30 and the cylindrical spindle 32 define a volume thereof. The crankshaft 22 is formed with a suitable rigid material sufficiently strong. The brake assembly 28 is of known construction and as such will not be described in detail herein. The brake assembly 28 is mounted on the crankshaft 22 and generally includes a brake drum 38 and a brake shoe 40. The wheel hub assembly 26 is mounted on one end of the crankshaft 22 and generally surrounds the spindle 32. The assembly of wheel hub 26 includes a metal wheel hub 42 having a wall 44 defining a space, cavity or chamber 46 between wheel hub 42 and spindle 32, a plurality of wheel bearings 48 and a hub cup 50 The wheel hub 42 is attached to the brake drum 38 by known suitable means, such as bolts 52. A semi-fluid synthetic fat bath 54 is contained within the wheel hub chamber 46. The semi-fluid synthetic grease. 54 lubricates the wheel bearings 48 and the crankshaft 22 during vehicle operation. A seal 56 of the sliding ring type is provided between the wheel hub 42"the crankshaft 22 to prevent the semi-fluid synthetic grease 54 from leaking out of the chamber 46 at the intersection of the wheel hub 42 and the crankshaft 22. The Wheel bearings 48 are mounted between the wheel hub 42 and the spindle 32 by a bearing cup 58 and a bearing cone 60. An internal adjusting nut 62 is threaded into the threaded end 36 of the spindle 32 and is supported against the bearing cone 68 and a shoulder 64"formed in the spindle 32 to position the wheel bearings 48. The adjusting nut 62 is locked on the spindle 32 by the thread of a washer 66 and an outer capping nut 68 on the threaded end 36. The wheel bearings 48 allow the wheel hub assembly 26 and the brake drum 38 to rotate relatively with respect to the fixed crankshaft 22. The bearings 48 are mounted on both sides of the chamber 46 and are lubricated. rich in the semi-fluid synthetic fat bath 54 contained within the chamber 46. The hub cup 50 includes a first solid cup member 70 attached to the end of the wheel hub 42 by a plurality of metal bolts or fastening members 72. , which are discussed in more detail in the present. A second solid cup member 74 attached to the outer face of the first cup member 70 by suitable means, and a sintered metal plug 76 attached to the center of the second cup member 74 by suitable means to prevent the formation of pressure within the wheel hub 42 can force the semi-fluid synthetic grease 54 through the sliding ring seal 56. The hub cup 50 seals the outer end of the hub chamber 46 and prevents the semi-fluid synthetic grease 54 from leaking of the end of the wheel hub assembly 26. The pins 72 preferably are in number of six, are spaced apart radially outwardly from a central line of the crankshaft 22. Each bolt 72 includes a threaded rod 178 that is five-sixteen inches in diameter (about .8 cm) and that depends on a head 180. A plurality of threaded holes is formed in the cup member 70 in positions that are approximately 1/8 inch (.32 cm) away from the bearing cups 58. Likewise a plurality of threaded blind holes are formed in the wheel hub 42 in positions approximately 1/8 of an inch out of the bearing cups 58. The holes and blind holes are aligned with each other and the threaded rod 178 of the respective pins 72 are threaded through them respectively to fix the cup of hub 50 on the wheel hub 42. The head 180 of each pin 72 sits against the outside of the cup member 70. The pins 72 only hold the cup member 70 to the end of the hub. wheel hub 42. There is no tear load applied to bolts 72. During vehicle operation, such as the wheel, wheel hub, 42, hub cup 50 and brake drum 38 rotate, heat is generated. This causes the semi-fluid synthetic fat 54 within the chamber 46 to increase in temperature. Also during operation some semi-fluid synthetic grease 54 may leak to the hub cup 50 through the space between the bearing cup 58 and the bearing cone 60 where the wheel bearings 48 are located and may escape through the seal of sliding ring 56.
With respect to the first embodiment of the invention as shown in Figures 1-3 in order to visually alert an operator that a dangerous temperature has been reached by the bearings 48 and the crankshaft 22, the visual indicator means are provided. novel features of the present invention. The bearings 48 and the crankshaft 22 can reach a dangerous temperature as a result of a variety of conditions. For example, the semi-fluid synthetic fat bath or bath 54 in chamber 46 overheats as a result of heating-up conditions. operation within the wheel mounting apparatus 24, due to a loss of grease 54 in the chamber 46, by contamination of the grease 54 or by a failure of the bearing cup 58 and / or the bearing cone 60. As shown in FIG. shown in Figures 1-3, the temperature test 20 forming the visual indicator means is removably mounted in a port 78 provided through the wall 44 of the wheel hub 42. The port 78 is threaded and is in communication with the chamber 46. When the temperature test 20 is removed from coupling with the port 78, the port 78 is used as a filling hole to fill the chamber 48 with semi-fluid synthetic fat 54. As best shown in the Figures 2 and 3, the pru Temperature probe 20 includes a housing such as cup 80, indicator pin 82, a spring 84 and a quantity of weld 86 mounted within housing 80. Housing 80 has a closed end and an open end at the opposite end thereof. A shoulder 88 is provided along the length of the interior wall of the housing. The indication pin 82 has a head 90 and a rod 92 extending therefrom. The rod 92 is inside the housing 80 and has a barbed end 94 which is inserted into the weld 86 that is provided at the closed end of the housing 80. The tines at the end 94 of the rod 92 ensure that the indicator pin 82 does not prematurely disengage from the weld 86. One end of the spring 84 sits against the shoulder 88 and the opposite end of the spring 84 sits against the head 90 of the indicator pin 82. The temperature test 20 is mounted securely on the a recess of a brass plug 98. The temperature test 20 is suitably determined within the brass plug 98, by means of a friction fit or by an adhesive. The brass plug 98 is threadedly mounted on the port 78. The brass plug 98, and thus the temperature test 20, can be removed from the coupling with the wall 44 of the wheel hub.42 by unscrewing the buffer 98. When the plug 98 and temperature test 20 are removed from the wheel hub 42, the semi-fluid synthetic fat 54 can be added to the chamber 46 through the open port 78. When the wheel, the wheel hub assembly 26 and the drum of brakes 38 rotate with respect to the crankshaft 22, heat is generated. If the bearings 48 are suitably lubricated during operation (a sufficient amount and quality of semi-fluid synthetic grease 54 is present in the chamber 46) or if a failure of the stroke does not occur, the head 90 of the indicator pin 82 remains in against the open end of the housing 80 as shown in Figures 1 and 2. If an insufficient quantity or quality of the semi-fluid synthetic fat 54 is present in the chamber 46 during operation so as not to adequately lubricate the bearings 48, or if a ring failure results, a temperature increase occurs within the chamber 48. When the temperature reaches a predefined level, (for example, the normal operating temperature of the crankshaft 22 is 83 ° C and 121 ° C. the weld 86) sufficient heat is transmitted to the weld 86 through the brass plug 98 to melt the weld 86. Once it has been fused, the barbed end 94 of the pin indicated r is released and the spring 84 guides the pin 82 out of the housing 80 until the barbed end 94 makes contact with the shoulder 88 within the housing 80. Once the operator sees the head 90 of the pin 82 moved away of "burst out" of the housing 80 as shown in Figure 3, you will know that it is necessary to conduct an investigation. The operator will remove the plug 98 and thus the temperature test 82 by unscrewing the plug 98 of the wheel hub 42 to perform a check as described herein, and add semi-fluid synthetic fats 54, if necessary to prevent a catastrophic failure of the bearings that would result if this condition were left undetected. As a technician will understand, the temperature test 20 can take many forms as long as the visual indication is provided to the user that a dangerous temperature has been reached in the crank 22. For example, the indicator pin 82 could be guided inwardly. . The plug 98 can be welded through a port in the wheel hub 42 and a second filler hole (which will have a closure member associated with it) can be provided to fill the chamber 46 with semi-fluid synthetic fat 54. Additionally, the plug 98 and the temperature test 20 can be designed as an integral member. With respect to the second embodiment of the invention shown in Figures 4-7, in order to visually alert the operator that a dangerous temperature has been reached by the bearings 48 and the crankshaft 22, the novel visual indicator means of the present invention is provided. Again, the crank 22 can reach a dangerous temperature as a result of many conditions, for example, the semi-fluid synthetic fat bath 54 in the chamber 46 has been overheated as a result of heating conditions within the wheel mounting apparatus 24, due to loss of grease 54 in chamber 46, or due to contamination of grease 54 or due to failure of bearing cup 58 and / or bearing cone 60. As shown in the drawings, the indicator of temperature 120 includes a temperature test 181 which is mounted on one of the bolts 72, which is preferably a cube cup bolt of degree 8. In this embodiment, port 78 of Figures 1-3 is replaced by a port Standard filling (not shown). As shown in Figure 5, a 3/16 inch, soft blind hole 182 is drilled in one of the pins 72. The blind hole 182 is aligned with the center line of the pin 72. The temperature test 181 is fixed by adhesive 184 within blind perforation 182. preferably adhesive 184 is applied as an 1/16 inch diameter urethane bead and temperature test 181 is twisted as it is inserted into blind perforation 182 in the pin 72. As best shown in Figures 6 and 7, the temperature test 181 includes a housing such as cup 186, a pin indicator 188, a spring 19Q and a quantity of weld 192 mounted within the housing 186. The housing 186 has a closed end and an open end at the opposite end thereof. A shoulder 194 is provided along the length of the interior wall of the housing 186. The indication pin 188 has a head 196 and a rod 198 extending therefrom. The rod 198 is inside the housing 186 and has a barbed end 200 that is embedded in the weld 192 that is provided at the closed end of the housing 186. The barbs at the end 200 of the rod 198 ensure that the indicator pin 188 does not prematurely disengage from the weld 192. One end of the spring 190 sits against the shoulder 194 and the opposite end of the spring 190 sits against the head 196 of the indicator pin 188. When the wheel, the wheel hub assembly 26 and the Brake drum 38 rotates with respect to the crank 22, heat is generated. If the bearings 48 are properly lubricated during operation (a sufficient quantity and quality of semi-fluid synthetic grease 54 is present in the chamber 46) or if there is no failure of the race of the bearing cup 58 and / or the bearing cone 60, head 196 of indicator pin 188 remains against the open end of housing 186 as shown in Figures 4 and 6. If insufficient quantity or quality of grease 54 is present in chamber 46 during operation for not being able to properly lubricate the bearings 48, or if a ring failure results, a temperature rise occurs within the chamber 46. When the temperature reaches a predefined level, (for example, the normal operating temperature of the crankshaft 22 is 83 ° C and 121 ° C. from welding 92) sufficient heat is transmitted to the weld 192 through the metal wheel hub 42 and the metal bolt 72 to melt the weld 192. Once the weld 192 has been fused, the barbed end 200 of the pin indicator 188 is released from it and spring 190 alters pin 188 out of housing 186 until the barbed end 200 makes contact with shoulder 194 within housing 186. Once the operator sees the head 196 of the indicator pin 188 moved away from or "popped out" of the housing 186 as shown in Figure 7, you will know that an investigation is necessary. The operator will perform a check as described herein, and add semi-fluid synthetic grease 54, through a wheel hub port 42, if necessary to prevent a catastrophic failure of the bearings that would result if this condition were left undetected. As a technician appreciates, the temperature test 181 can have different shapes as long as the visual indication is provided to the user that a dangerous temperature has been reached in the crank 22. For example, the indicator pin 188 could be guided inwardly. Bolt 72 and temperature test 181 can be designed as an integral member. Also if desired, the temperature test 181 could be provided in more than one pin 72. One benefit of providing the temperature test 181 in one of the pins 72, is that this invention can be easily retrofitted to the existing apparatuses, such as a wheel mounting apparatus 24, without the need to modify the existing structure. Although a preferred embodiment of the present invention has been shown and described, it is apparent to the artisan that numerous modifications of the present invention exist without departing from the spirit and scope of the claims. The invention is not intended to be limited by the foregoing description.