GB2085098A

GB2085098A - Friction Clutches and Brakes

Info

Publication number: GB2085098A
Application number: GB8032046A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-10-04
Filing date: 1980-10-04
Publication date: 1982-04-21

Abstract

A clutch or brake has grooved, interfitting friction surfaces to increase their effective area of contact, the grooves having straight or curvilinear flanks. The friction materials may have coefficients of expansion selected to ensure increased frictional engagement with increasing temperature. <IMAGE>

Description

SPECIFICATION Improvements to Friction Clutch and Brake Mechanism This invention relates generally to clutch and brake mechanisms of such types wherein the frictionally-involved surfaces are controllably engaged under varyingpressure applied perpendicularly to the said surfaces.

Particularly, by this invention, the normally plain friction surfaces, which are typical in the background art, are, instead, variously formed so as to evince alternate ridges and grooves, hereinafter termed corrugations, aligned parallel to the motion with which the respective mechanisms are functionally associated. The said surfaces, so corrugated, are positioned relatively within the respective mechanisms so as to establish, when engaged, an unbroken area of frictional contact greater in extent than that occurring in the engagement of similarlyproportioned, uncorrugated surfaces; but without entailing a corresponding increase in overall, installational dimensions.

This concept is illustrated in Figs. 1, 2, 3 and 4, of the accompanying drawings which, not to scale, are part-cross-sectional representations of different examples, from a substantially infinite geometrically variable range, of engaged corrugated sun'aces, as viewed in a direction tangential to the said functionally associated motion.

In each of these drawings the line N-N represents, for visual comparison, the contact between uncorrugated surfaces such as are characteristic of the types prevailing in the said background art; and when related lengthwise, over any lateral dimension, to the indented or sinuous line denoting the engagement of the corrugated surfaces, the greater extent of the latter is clearly indicated.

Referring now to Figs. 1 and 2, the corrugations depicted are examples of a variable range of generally rectilinear, indented forms suitably modified by radii on the tips and in the roots in order to strengthen these features and to protect them from operational or inadvertent damage. Figs. 3 and 4, depict examples from the similarly variable range of sinuous, curvilinear corrugations.

The forms exemplified in Figs. 1 and 4, inclusive are determined in accordance with functional, material and manufacturing considerations, the interrelationship of these factors being readily ascertainable. The greatest practicable increase in frictional area afforded by this invention is calculable and achieved by equilibrating the maximum practicable depth or amplitude of the corrugations with the closest possible and practicable pitch or spacing thereof.

The frictional materials selected for use in this condition will necessarily possess appropriate coefficients of expansion in order to produce, in operation, a suitable additional degree of lateral, heat-induced engagement between the flanks of the contiguous corrugations and, because of the thinness of the material sections involved, will be of sufficiently high tensile strength to prevent disintegration or any substantial deterioration in durability, resultant from the effects of the maximum operatively-applied pressure. Such materials may be selected from an extensive range of metals, alloys, cermet or other suitable substances.Enhanced durability of these surface materials, due to wider dispersal of functional stresses over the said relatively increased corrugated contact area, whereof the features are, operatively, continually self-regenerative, is a clear corollary.

The corrugations are, when operating under varying degrees of ambient or frictionallygenerated heat, productive of a high factor of component rigidity with a correspondingly low propensity for physical distortion and, due to the generally inherent characteristics of most corrugated surfaces, conducive to a rapid dissipation of the said heat by radiation and conduction.

Manufacture of the frictional components characterized by this invention, either for new assemblies or as replacements for outworn units, is readily achieved by the use of standard production methods and equipment.

The procedure for installing the said replacement components in generally typical drum-brake and plate-ciutch mechanisms is substantially in accordance with existing practice, whilst in the case of disc-brakes of the type incorporating removable hydraulic piston subassemblies or other actuating devices, little, if any, modification of calliper design is needed.

Claims

1. Friction clutch and brake mechanisms as hereinbefore described and illustrated wherein the operationally-engaged friction surfaces are so formed as to possess alternate ridges and grooves, hereinafter termed corrugations, aligned parallel to the direction of the motion with which the respective mechanisms are functionally associated, and positioned relatively in the assembled mechanisms so as to establish an unbroken area of frictional contact under controllably-applied operative pressure.

2. Clutch and brake mechanisms as claimed in Claim 1, and exemplified in Figs. 1, 2, 3, and 4, of the accompanying part-sectional drawings wherein the magnitude of the said area of frictional contact is, though readily calculable, visually indicated by a lengthwise comparison between any particular extent of line N-N, representing an area of plain surface contact such as prevails in the background art, and the line representing the contact between corrugated surfaces across the same lateral extent.

3. Clutch and brake mechanisms as claimed in Claims 1 and 2, wherein all forms of corrugations, selected to be compatible with particular material characteristics, functional requirements and manufacturing considerations, are operationally

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements to Friction Clutch and Brake Mechanism This invention relates generally to clutch and brake mechanisms of such types wherein the frictionally-involved surfaces are controllably engaged under varyingpressure applied perpendicularly to the said surfaces. Particularly, by this invention, the normally plain friction surfaces, which are typical in the background art, are, instead, variously formed so as to evince alternate ridges and grooves, hereinafter termed corrugations, aligned parallel to the motion with which the respective mechanisms are functionally associated. The said surfaces, so corrugated, are positioned relatively within the respective mechanisms so as to establish, when engaged, an unbroken area of frictional contact greater in extent than that occurring in the engagement of similarlyproportioned, uncorrugated surfaces; but without entailing a corresponding increase in overall, installational dimensions. This concept is illustrated in Figs. 1, 2, 3 and 4, of the accompanying drawings which, not to scale, are part-cross-sectional representations of different examples, from a substantially infinite geometrically variable range, of engaged corrugated sun'aces, as viewed in a direction tangential to the said functionally associated motion. In each of these drawings the line N-N represents, for visual comparison, the contact between uncorrugated surfaces such as are characteristic of the types prevailing in the said background art; and when related lengthwise, over any lateral dimension, to the indented or sinuous line denoting the engagement of the corrugated surfaces, the greater extent of the latter is clearly indicated. Referring now to Figs. 1 and 2, the corrugations depicted are examples of a variable range of generally rectilinear, indented forms suitably modified by radii on the tips and in the roots in order to strengthen these features and to protect them from operational or inadvertent damage. Figs. 3 and 4, depict examples from the similarly variable range of sinuous, curvilinear corrugations. The forms exemplified in Figs. 1 and 4, inclusive are determined in accordance with functional, material and manufacturing considerations, the interrelationship of these factors being readily ascertainable. The greatest practicable increase in frictional area afforded by this invention is calculable and achieved by equilibrating the maximum practicable depth or amplitude of the corrugations with the closest possible and practicable pitch or spacing thereof. The frictional materials selected for use in this condition will necessarily possess appropriate coefficients of expansion in order to produce, in operation, a suitable additional degree of lateral, heat-induced engagement between the flanks of the contiguous corrugations and, because of the thinness of the material sections involved, will be of sufficiently high tensile strength to prevent disintegration or any substantial deterioration in durability, resultant from the effects of the maximum operatively-applied pressure. Such materials may be selected from an extensive range of metals, alloys, cermet or other suitable substances.Enhanced durability of these surface materials, due to wider dispersal of functional stresses over the said relatively increased corrugated contact area, whereof the features are, operatively, continually self-regenerative, is a clear corollary. The corrugations are, when operating under varying degrees of ambient or frictionallygenerated heat, productive of a high factor of component rigidity with a correspondingly low propensity for physical distortion and, due to the generally inherent characteristics of most corrugated surfaces, conducive to a rapid dissipation of the said heat by radiation and conduction. Manufacture of the frictional components characterized by this invention, either for new assemblies or as replacements for outworn units, is readily achieved by the use of standard production methods and equipment. The procedure for installing the said replacement components in generally typical drum-brake and plate-ciutch mechanisms is substantially in accordance with existing practice, whilst in the case of disc-brakes of the type incorporating removable hydraulic piston subassemblies or other actuating devices, little, if any, modification of calliper design is needed. Claims

3. Clutch and brake mechanisms as claimed in Claims 1 and 2, wherein all forms of corrugations, selected to be compatible with particular material characteristics, functional requirements and manufacturing considerations, are operationally self-regenerative during their operative lives.

4. Clutch and brake mechanisms as claimed in Claims 1, 2 and 3, wherein the expansion coefficients of any materials from which any of the opposing surfaces is manufactured produces a proportionate amount of lateral frictional activity between the flanks of contiguous corrugations, thus intensifying the initial frictional effect resulting from the perpendicularly-applied operative pressure.

5. Clutch and brake mechanisms as claimed in Claims 1 and 4, inclusive wherein the said materials may be selected from a wide range of metals, alloys, cermet or other substances possessing suitably high degrees of tensile strength.

6. Clutch and brake mechanisms as claimed in Claims 1 to 5, inclusive wherein the said corrugations are, under varying degrees of ambient or frictionally generated heat, conducive to a high factor of component rigidity with a correspondingly low propensity for physical distortion and, due to the inherent characteristics of the corrugated surfaces, to a rapid dissipation of the said heat by radiation and conduction.

7. Clutch and brake mechanisms as claimed in any preceding claim, wherein the manufacture of frictional components characterized by this invention, either for original assembly or replacement purposes in a range of various applications, may be readily achieved by the use of standard production methods and equipment.

8. Clutch and brake mechanisms as claimed and characterized in all preceding claims.