Power transmission belt and a process for its manufacture
View Patent ↗An endless power transmission belt having a internal lubricating agent-containing fabric element extending along at least the pulley-engaging, power-transmitting surface of the belt, as well as processes for manufacturing same. More particularly, an endless toothed belt having a wear-resistant fabric cover element that comprises at least one internal lubricating agent in the form of one or more clusters within at least a portion of the total thickness of the fabric element.
1. A method for producing a power transmission belt possessing a belt length and a flexible body portion, comprising the steps of:
a) applying to a fabric element possessing a first surface and a second, opposite surface an internal lubricating agent to form a treated fabric, and;
b) disposing said treated fabric against a material for forming said flexible body portion; characterized in that the method further comprises the step of;
c) causing at least a portion of said internal lubricating agent to form at least one cluster of said internal lubricating agent within at least a portion of the total thickness of the fabric; wherein said lubricating agent is applied as part of a mixture further comprising a carrier constituent in substantial absence of a binder constituent.
2. The method of claim 1 wherein said mixture further comprises a rheology-modifying agent.
3. The method of claim 2 wherein said rheology-modifying agent is added in a quantity sufficient to adjust the viscosity of said mixture to within the range of from about 3000 cp to about 10,000 cp.
4. The method of claim 1 further comprising the step of causing at least a substantial portion of the carrier constituent to liberate from said fabric element after application of said mixture to said fabric element.
5. The method of claim 1 further comprising the step of applying the internal lubricating agent so as to effect an imbalanced concentration of internal lubricating agent within the fabric element, with a higher concentration of internal lubricating agent proximal said first surface of the fabric element, and a lower concentration thereof at least a point within the total thickness of the fabric element.
6. The method of claim 5 wherein said step of applying the internal lubricating agent within the fabric element comprises at least one of
(a) knife-coating or roll-coating said internal lubricating agent onto only one of the two surfaces thereof, and
(b) dipping said fabric element in a vessel containing said internal lubricating agent and causing said fabric element to be drawn about at least one roller member.
7. The method of claim 1 further comprising the step of applying to at least a second surface of the fabric element an adhesive treatment comprising at least one adhesive ingredient.
8. The method of claim 1 further comprising the step performed at any point prior to application of said fabric element to said material for forming said body portion, of applying to at least said first surface of the fabric element an outer layer comprising at least one of a rubber ingredient, a resin ingredient, a plastic ingredient, and a second lubricating agent.