Patent GB-1132976-A (GB)
Title: Gear drive mechanism
IPC: F16H29/00
Filed: 1965-11-24
Abstract: 1,132,976. Toothed gearing; variable-speed ratchet gearing. CANADA MACHINERY CORP. Ltd. 24 Nov., 1965 [24 Nov., 1964 (2)], No. 50036/65. Headings F2D and F2Q. [Also in Division B3] In a drive mechanism comprising two output shafts driven from a common main input shaft, the output shafts are respectively connected to first and second elements of an epicyclic gear arrangement and an auxiliary input drive operative during only a first part of one revolution, or a series of revolutions, of one of the output shafts is operative to rotate, by a given but adjustable amount, a third, carrier, element of the epicyclic gear arrangement through one-way clutch means to change the amount of rotation of one or both of the output shafts during said first revolution part of said one output shaft, the arrangement being such that the two output shafts rotate in synchronism during a second revolution part of said one output shaft. The two output shafts are used to drive respectively a machine feeding continuous lengths of material and a following machine performing repeated operations on material fed thereto, such machines respectively including, e.g., a pinch roll stand or roller leveller, and a shearing, stamping, pressing, processing, fabricating, forming or printing machine for metal strip, paper, plastics, rubber or synthetic rubber. In Fig. 1, an input shaft 42 drives a shear drive shaft 39 through gears 43, 44, and a pinch roll stand drive-shaft 38 through the gears 43, 44 and a three-element epicyclic gear 46. The epicyclic casing 48, forming the third epicyclic element, is fast with a control shaft 47 which is arranged to be cyclically rotated, during a first part of a revolution of the shaft 39, through a rack and one-way clutch 52, 51 ratchet drive, by a cylinder motor 53 on receipt of a signal from a signal generator 54 actuated by the shaft 39, to add or subtract rotation to or from the shaft 38. A back-stop 55 prevents reverse rotation of the shaft 47. During the second part of the revolution of the shaft 39 the shaft 47, together with the epicyclic easing 48, is braked, to synchronize the shafts 38, 39, by a brake 56 controlled by the shaft 39. The rack stroke is adjustable by action on the cylinder motor or rack/one-way clutch connection. In Fig. 2 (not shown), the control shaft 47 is cyclically rotated by the shaft 39 through two offset crank/connecting rod/one-way clutch adjustable ratchet drives. In Fig. 3 (not shown), the two ratchet drives are connected to the control-shaft 47 through a further threeelement epicyclic gear. In alternative embodiments, the pinch roll stand drive-shaft 38 may be directly driven and the shear drive-shaft speed cyclically varied. A brake (47a), imparting a constant drag on the control shaft 47, is spring-loaded and thereby locates the control shaft against a back-stop during the period when no motion is applied to the control shaft. In Fig. 4, the mechanism comprises two interconnected three-element epicyclic gears 111, 119 respectively comprising a casing element 113 and two elements connected to gears 115, 116, and a casing element 121 and two elements connected to gears 123, 122, the latter respectively meshing the gear 116 and a gear 114 fast on the casing 113. Input from a motor 110 is to the gear 115. Drives to shear drive and pinch roll stand shafts 107, 108 are respectively taken from the gears 122, 116. A control shaft 120 fast with the casing element 121 is arranged to be cyclically rotated during a first part of a revolution of the shaft 107 through a variable ratchet drive. The latter comprises a crank 129 fast on the shaft 107 and acting via a link 128 on a rockable post 130. A rack 132 adjustable along and pivoted to the post 130 meshes a gear 134 connected to the shaft 120 through a oneway clutch 133. Rotation of the control shaft 120 adds and subtracts rotation simultaneously to the shafts 107, 108 or vice versa. During the second part of the revolution of the shaft 107, the shaft 120, together with the casing 119, is braked, to synchronize the shafts 107, 108, by a brake 135 actuated by a cam 136 on the shaft 107. To prevent runaway of the shaft 108, gear element overrun, unloading of the gear trains, or backlash when the strip is cut, a constant drag is imposed on the shaft 108 by a drag generator or stabilizer brake 140, and, additionally, the roll stand 106 or leveller can function as a constant load. The epicyclic gear 111 is shown (Fig. 5, not shown), as comprising bevel planets rotatably carried in the casing 113 and meshing side wheels integral with the gears 115, 116. In Fig. 9 (not shown), the gears 115, 122 are connected together via the gear 126 fast with the shaft 107, the input is to the casing 113, and the control shaft 120 is cyclically rotated in response to rotation of the shaft 108 via a variable ratchet drive comprising an eccentric (152) driven by the shaft 108 and acting via a connecting-rod (156), a link (154) and a one-way clutch (144). A speed control arm (155) connected to the connecting-rod (156) has a pivot (151) arcuately adjustable to vary the ratchet drive. The cyclic rotation of the control shaft may be effected independently of the output drive-shafts by a power source independently controlled.