Patent GB-191312943-A (GB)
Title: Improvements in Variable Speed Power Transmission Devices.
Inventor: WEISS CARL WILLIAM
IPC: F16H61/664
Filed: 1913-06-04
Granted: 1914-06-04
Abstract: 12,943. Weiss, C. W. June 4. Variable-speed gearing. - A variable-speed power - transmission mechanism depends essentially upon the action of a nutatory intermediate member in relation to a concentric co-operating member, one of the members having an internal or external spherical bearing-surface, and the other having rolling elements with a lateral clutch-like action co-operating with the spherical bearing-surface. The clutch-like action constrains the rolling elements always to travel in a direction perpendicular to their axes and therefore when impelled by the nutating movement to trace zigzag paths around the bearing- member, the rotary component of the zigzag motion being transmitted from one or the other member to the element to be driven. By adjustment of the inclination of the nutatory member, the form of the zigzag path traced and the consequent rotary component of the motion tu be transmitted may be varied. In the arrangement shown in Figs. 2 and 5, the nutatory member i carries the rolling clutch-like elements k which engage the internal spherical bearing- surface h of the co-operating member, constituting in this case the fixed casing parts h<1>, h<2>. The nutatory member i is connected to the driving-shaft a by means of an adjustable inclined crank-arm g, and to the driven shaft m by means of a universal joint m<3>, m<5>. The rollers k are mounted on ball bearings on spindles k<2> and are arranged in radial slots i<6> in the member i. The spindles k<2> are supported upon rollers k<3> mounted on spindles k<4> and arranged in a circumferential groove in the member i. The rollers k are therefore capable of a lateral movement in the radial slots i<6> which sets up a wedging clutch-like action with the fixed spherical bearing-surface h thereby preventing any degree of movement of the rollers k except in a direction perpendicular to their axes. The crank g, actuating the nutatory member i, is arranged in a slot a<4> in the enlarged head a<1> of the driving-shaft a and is pivoted in the end of an axially adjustable rod c carried in the bored end of the shaft a and arranged to rotate therewith. The outer end of the crank g is forked and carries the trunnions i<4> of a two-part sleeve i<2> which embraces a cylindrical stud secured at i<1> to the nutatory member i, the sleeve being held on the stud by a large-headed screw secured in the end of the stud. When the driving-shaft a is rotated, the outer end i<4> of the crank g rotating in a circle imparts a simple nutatory movement to the member i. Under the influence of the nutatory motion, the rollers k, being constrained always to travel in a direction at right-angles to their axes, travel in zigzag paths around the fixed spherical bearing-surface h, thus imparting a forward rotation to the nutating member i, which is transmitted to the driven shaft m. When the adjustable nutatory member i is at right-angles to the axis of the driving-shaft a, no motion is transmitted, the speed of the shaft m gradually increasing with the obliquity of the member i to the neutral position of perpendicularity. The obliquity of the nutatory member i is determined by axial adjustment of the rod c in the shaft a, this being effected by means of a forked lever f carrying a collar e engaging a grooved sleeve d connected to the rod c by pins c<1> passing through longitudinal slots a' in the shaft a. Axial movement of the shaft a in the bearing-support b is prevented by the head a<1> and a collar a<2>. In the modified arrangement shown in Fig. 8, the rolling clutchlike elements comprise balls k in a cage k<7>, each ball resting upon a short flattened peripheral portion of the nutatory member i to effect the lateral clutching action. In this arrangement, the nutatory member, instead of being directly jointed to the driven shaft m, is itself formed with an internal spherical bearing- surface i<7> co-operating with a second series of balls m<9> mounted in a cage m<10> and resting on flattened peripheral portions of the member m' carried by the shaft m. By this means, the rotary movement of the nutatory member i, derived as in the previous arrangement, is directly conveyed to the shaft m through the clutching-elements m<9>, together with an additional forward rotary motion of the shaft m resulting from the nutating movement of the spherical bearing - surface i<7> upon the non- nutatory rolling elements m<9>. Other modifications shown in this Figure consist in pivoting the crank member g directly in the end a<4> of the driving - shaft a and rendering the shaft itself axially adjustable by means of the lever f. The crank g is counterbalanced at g<2> and is formed with a toe g<1> which bears against the nutatory member i to facilitate adjustment from the neutral position shown in Fig. 8, subsequent adjustment being effected through the sleeve i<2> on the stud i<1> as in the previous arrangement. The co-operating member h<3>, having the internal spherical bearing-surface h, instead of being rigidly fixed, is held between parts h<4>, h<5> of the casing, which are drawn together adjustably by springs h<7> on bolts h<6>, providing means whereby the member h<3> may slip under excessive strain to obviate breakage. In a further modification having a double set of rolling elements as shown in Fig. 8, cylindrical rollers, as previously described, are used but are differently mounted, the spindles of the rollers being mounted in ball bearings in rings, which are axially slidable in semicylindrical seatings formed on the periphery of the nutatory member i and on the co-operating member secured to the shaft m, respectively. In the arrangement shown in Fig. 10, the internal spherical bearing-member h<8> is arranged within a casing comprising a cylindrical shell h<10> and end members h<9>, h<11>, and is normally secured thereto between friction plates h<12>, h<13> by means of an adjustable head h<14> pressed into action by spring-controlled studs h<15>, as shown in Fig. 11, but capable of being withdrawn to release the member h<8>, whereby the drive is no longer transmitted to the shaft m. The head h<14> is withdrawn by means of a lever h<17> having screwthreaded engagement with the boss or hub thereof. Means are also shown in Fig. 10 to clutch the parts together to effect a direct drive. For this purpose, the plate h<13> is secured to the bearing-member h<8> and is arranged between a plate m<11> keyed to the shaft m, and a looselymounted plate m<12>. The hub of the plate m<11> is formed with an annular shoulder m<13>, and the nutatory member i is formed with an annular rim i<8>, so that when the member i is adjusted to its extreme position, the rim i<8> engages the shoulder m<13>, pressing the plates m<11>, m<12> together to grip the plate h<13> to effect a direct drive, the clamping-head h<14> having been previously withdrawn. In the arrangement shown in Fig. 11, the rollers k are not axially displaceable but are yieldingly supported by the nutating member which is formed with cuts or slots extending from its rim nearly to its base. Within the nutating member is arranged a carrier n, held in position by a stud n<1> engaging an axial recess therein. A series of balls n<3> are arranged in shallow tapered pockets in one or both members and act as wedging elements to expand the nutatory member to effect an' efficient frictional gap between the rollers and the spherical bearing-surface.