STRAIGHT LINE SHEAR

Abstract: The shear has a drive incorporating a pinion (56) for reciprocating racks (48,54) which are secured to slides (24,26) of the shear. The pinion is rotated first in one direction and then in the opposite direction to cause the blades (28,30) of the shear mounted on the slides to first move together and shear a gob, and then move back to the original position. The drive for the pinion may be an electrical servo motor (68) or another type of servo motor.

Description: This invention relates in general to new and useful improvements in straight line shears for cutting glass runners into individual gobs, and more particularly to improved rotary drives for such shears. This invention, in particular, constitutes a modification on the shear drive disclosed in United States Patent No. 4 215 611 to Francis A. Dahms, granted August 5, 1980 assigned to the assignee of the present invention. The disclosure of the aforesaid patent is incorporated herein by reference. It is known to provide a straight line shear wherein there are two slides mounted for guided movement towards and away from one another, and arranged in opposed relation. The slides carry cooperating blades. The slides are driven by racks which are interconnected by a pinion. The drive unit is in the form of a double-acting air cylinder or linear air motor which is coupled to one of the racks between that rack and an associated one of the slides. In accordance with this invention, there is provided a rotary drive which is coupled to a pinion to effect rotation of the pinion which, in turn, will reciprocate both racks in the required opposite direction. On the one hand such a rotary drive unit may be in the form of an electrical servo motor. Such an electrical servo motor will be controlled by a microprocessor together with a servo controller power switching device. On the other hand, the rotary drive unit may be in the form of electric-hydraulic stepping motor or a hydraulic rotary motor with an electric hydraulic control valve. The rotary drive unit may be directly coupled to the pinion or may be coupled thereto by way of spur gears or bevelled gears, When bevelled gears are utilised, the rotary drive unit may be disposed parallel to the drive mechanism. In accordance with the present invention, the double-acting air cylinder normally would be discarded. On the other hand, it is feasible to utilise in conjunction with the double-acting air cylinder a rotary drive unit which would provide the required supplemental torque during the shearing operation. It is also feasible to provide a unidirectional drive unit which would be coupled to a converter having a one direction input and a reversing output. In the drawings, wherein throughout like numerals refer to like parts: Figure 1 is a schematic plan view showing one embodiment of straight line shear utilising an electro servo motor coupled to the drive pinion by a bevelled gear; Figure 2 is a wiring schematic for the servo motor; Figure 3 is a velocity profile for the shear; Figure 4 is a schematic plan view similar to Figure 1 but of an embodiment wherein the rotary drive unit provides a supplemental torque to a double-acting air cylinder; Figure 5 is an enlarged fragmentary vertical sectional view taken generally along the line 5-5 of Figure 4 and shows the specifics of the rack and pinion type drive; Figure 6 is a graph showing the velocity profile of the shear shown in the embodiment of Figure 4; Figure 7 is another schematic plan view of a modified form of shear drive incorporating a one-direction rotation rotary drive unit utilising a direction converter; Figure 8 is a schematic perspective view of the motion converter; Figure 9 is a graph showing the velocity profile of the shear shown in the embodiment of Figure 7; Figure 10 is a fragmentary view showing the rotary drive unit of Figure 1 directly coupled to the pinion of the drive assembly; Figure 11 is a fragmentary view similar to Figure 10 and shows the rotary drive unit connected to the pinion utilising spur gears; Figure 12 is a fragmentary schematic view showing the rotary drive unit as an electric-hydraulic stepping motor; and Figure 13 is another fragmentary schematic view showing the rotary drive unit as a rotary hydraulic motor with an electric-hydraulic control valve. Referring now to the drawings in detail, reference is first made to Figure 1 wherein there is illustrated a straight line shear generally identified by the numeral 20. This shear, in simple terms, includes a support or frame 22 which has suitable guides for a pair of opposed slides 24, 26 which are mounted within the support 22 for simultaneous reciprocation towards and away from one another. The slides 24, 26 carry blades 28, 30 which cooperate with one another for the purpose of shearing a glass runner to form gobs. Although two sets of blades 28, 30 have been illustrated, it is to be understood that the shear may incorporate but a single set or may include as many as three sets or more. The slide 24 has a bracket 32 to which there is connected an actuating rod 34. The slide 26 has a similar bracket 36 to which there is coupled an actuating rod 38. The actuating rods 34, 38 are reciprocated by a drive assembly generally identified by the numeral 40. Reference is now made to Figure 5 wherein there is illustrated a typical drive, such as the drive 40. It will be seen that the support 22 includes a mounting plate 42 which carries a housing 44. The housing 44 has mounted therein a guide tube 46 in which there is guidingly mounted one end of the rod 34. The terminal portion of the rod 34 includes a rack 48. The housing 44 carries a second guide tube 50 in which there is guided for reciprocation an end portion 52 of the rod 38. The end portion 52 is also provided with a rack 54 which opposes the rack 48. A pinion 56 is positioned between the racks 48, 54 and is meshed therewith. The pinion 56 is keyed to a drive shaft 58 which is suitably rotatably journalled within the housing 44. In accordance with the embodiment of the invention illustrated in Figure 1, the housing 44 is provided on one side thereof with an adaptor plate 60 to which there is secured a right angle drive 62 which includes a shaft 64 which may be a continuation of the shaft 58 or directly coupled thereto. The right angle drive 62 has cooperating mitre or bevelled gears which are driven through a drive shaft 66 of an electrical servo motor 68. It is to be understood that the servo motor 68, when actuated, would rotate first in one direction and then reverse its direction of rotation so that the blades 28, 30 will be first advanced together to effect the shearing operation, and then separated to their original positions. Referring now to Figure 2, it will be seen that there is illustrated a schematic of the drive for the electrical servo motor 68. Actuation of the servo motor 68 is primarily by means of a microprocessor which provides the shear motion profile, the microprocessor being identified by the numeral 70. The microprocessor 70 has an output 72 connected to a servo controller 74 which effects power switching. The servo controller 74 has an output 76 connected to a control head 78 of the servo motor 68 for controlling actuation of the servo motor 68. The control system includes a feedback 80 from the control head 78 to the microprocessor 70. There is also a tachometer feedback 82 from the control head 78 to the servo controller. Figure 3 is a graph plotting velocity against time showing that the shear equipped with the servo motor 68 as illustrated in Figure 1 will have a rapid acceleration to a maximum speed, then a constant speed followed by a rapid deceleration. After the cut or shear occurs, the acceleration and deceleration are reversed. Although the servo motor 68 has been illustrated in Figure 1 as being connected to the shaft 58 through a right angle drive, it is to be understood that the servo motor 68 may be at right angles to the position of Figure 1, as is shown in Figure 10, and directly coupled to the pinion shaft 58. On the other hand, the servo motor 68 may be coupled to the pinion shaft 58 by spur gears 84 as is shown in Figure 11. Further, it is to be understood that the servo motor 68 may be replaced by an electro-hydraulic stepping motor system 86, as shown in Figure 12, which includes a rotary hydraulic motor 88 supplied with hydraulic fluid by a pump 90 which is driven by a stepping electrical motor 92. The pump 90 is supplied from a reservoir 94 which receives spent hydraulic fluid from the hydraulic motor 88 through a return line 96. In Figure 13 there is illustrated another utilisation of a hydraulic motor. In this embodiment a rotary hydraulic motor 98 is directly coupled to the pinion shaft and the operation thereof is controlled by an electrical or solenoid control valve 100 which controls flow from a pump 102 of hydraulic fluid under pressure. The pump 102 receives the hydraulic fluid from a reservoir 104 which receives the return from the hydraulic motor 98. Reference is once again made to Figure 5 wherein it will be seen that the rod 38 is actually a piston rod of a double-acting linear air motor or cylinder generally identified by the reference numeral 106. The air motor 106 includes a cylinder 108 in which a piston 110 is mounted, and which piston 110 has a piston rod 112 which is coupled to or may form the rod 38. The piston rod 112 also extends out through the opposite end of the cylinder and is connected to the rod portion 52. From the description of Figure 5, it will be seen that the shear may be actuated utilising the double-acting air motor 106. However, it has been found that beneficial results may be obtained with the shear arrangement shown in Figure 4 and generally identified by the numeral 116. The shear 116 is identical to the shear 20 with the exception of the incorporation of the double-­ acting air cylinder 106. In this embodiment of the shears, the servo motor 68, or similar motor, may be utilised to supplement the drive provided by the air cylinder 106. It is to be understood that the servo motor 68 will be driven in the manner described with respect to the shear 20. In this embodiment of the invention, sufficient air pressure is supplied to the air cylinder 106 to move the shear in excess of the desired cutting velocity. The microprocessor 70 provides a signal to the electric air control valve to apply air to the cylinder to move the shear for the cutting of a gob. However, if the right angle is a locking worm and wheel gear reducer 118, the air motor cannot actuate the shear until the servo motor 68 permits such movement. Thus, the servo motor 68 controls the motion of the cutting stroke and the air motor provides the power. Further, and most particularly, the torque applied to the pinion by the servo motor supplements the force applied to the shear by the air cylinder. It is to be understood that both the air to the air cylinder and the direction or rotation of the servo motor is reversed for the return stroke of the shear. A typical velocity profile for the shear arrangement of Figure 4 is shown in the graph of Figure 6. Reference now is made to the embodiment of Figure 7 wherein there is illustrated a shear generally identified by the numeral 120. The shear 120 will be identical to the shear 20 with the exception of the rotary drive unit. In lieu of the servo motor 68 being coupled to the pinion shaft 58 by way of a conventional right angle drive, there is an oscillating drive 122 between the servo motor 68 and the drive unit 40. The drive 122 may be a purchased item and is best illustrated in Figure 8. The illustrated drive unit 122 may be what is conventionally known as a Ferguson drive, or the equal. The drive 122 will be provided with a one-direction rotational input shaft 114 and an oscillating or reversing rotation output shaft 117. Thus, the servo motor 68 or other type of drive motor need not be of the reversing type. Figure 9 is a graph showing the plotting of velocity against time for the shear 120 illustrated in Figure 7. It is to be understood that the electric servo motor 68 may be replaced with other types of drive motors as previously discussed. It is also to be understood that the specific drives for the various shear arrangements discussed hereinabove provides for high-speed operation with maximum control so that the shearing of gobs may be increased while at the same time the resistance to the movement of the glass runner by the blades of the shear may be decreased.

Claims: 1. A straight line shear for forming glass gobs and the like, said shear comprising a pair of opposed slides (24,26) carrying opposed blades (28,30), guide means mounting said slides for movement along a predetermined path, and drive means (40) for first simultaneously moving said slides together in a shearing operation and then simultaneously moving said slides apart to a starting position, characterised in that said drive means comprising a pair of opposed spaced apart racks (48,54), a pinion (56) meshed with both of said racks whereby when said pinion is rotated said racks move in opposite directions, and a rotary drive unit (68,86,98) coupled to said pinion for first rotating said pinion in one direction through a preselected angle and then rotating said pinion in a reverse direction through the same angle. 2. A shear according to claim 1, characterised in that said rotary drive unit comprises a servo motor (68,86). 3. A shear according to claim 1, characterised in that said rotary drive unit comprises an electric servo motor (68) having a microprocessor motion control (70). 4. A shear according to either one of claims 2 and 3, characterised in that the servo motor (68,86) has rapid acceleration and deceleration with an intermediate maximum speed phase. 5. A shear according to any one of claims 2 to 4, characterised in that the servo motor (68,86) is of the direction of rotation reversing type. 6. A shear according to claim 1, characterised in that said rotary drive unit comprises an electro-hydraulic stepping motor (86). 7. A shear according to claim 1, characterised in that said rotary drive unit comprises a hydraulic rotary motor (98) having an electric hydraulic control valve (100). 8. A shear according to any one of claims 1 to 7, characterised in that there is a direct connection between said pinion (56) and said rotary drive unit (40). 9. A shear according to any one of claims 1 to 8, characterised in that there is a gear coupling (84) between said pinion (56) and said rotary drive unit (40). 10. A shear according to any one of claims 1 to 8, characterised in that there is a bevel coupling (62) between said pinion (56) and said rotary drive unit (40). 11. A shear according to claim 1, characterised in that said rotary drive unit (40) comprises a unidirectional power unit (68) and a one-direction transfer device (122) having a reversing output. 12. A shear according to claim 1, characterised in that said rotary drive unit (40) is a supplement drive, and there is a primary drive in the form of a double-acting linear fluid motor (106) coupled to one of said racks. 13. A shear according to claim 12, characterised in that said rotary drive unit includes a servo motor (68) and a locking worm gear and worm wheel (118).

Inventors: KULIG, CONSTANTINE W.
Applicants: EMHART INDUSTRIES, INC.
Application year: 1986
Main classification: C03B7
IPC codes: B26D1, C03B7