Meter base drive assembly

Abstract: A meter base drive assembly (4) is a part of a postage meter base (2), to which a postage meter is mounted. The assembly includes envelope drive (62), a tape dispenser (86) and a print head drive (84) mounted to a base frame (12). The drive assembly includes a motor drive (6), pivotally mounted (10, 14) to the frame, which drives a pulley (8) in a first rotary direction. First, second and third driven pulleys (16, 18, 56) are operably coupled to the envelope drive, print head drive and tape dispenser respectively. A dual pulley (20), including first and second pulley elements (28, 53), is pivotally mounted (34, 36 ; 102, 104) to the frame. One side (30) of a first drive belt (26) engages the drive pulley and one of the first and second driven pulleys. The second side (32) of the first drive belt engages the first pulley element. A second drive belt (52) engages the second pulley element and the other of the first and second driven pulleys, so that the first and second driven pulleys are rotated in opposite rotary directions.

Description: Various types of metering products are in common use. The most common type is used to dispense postage by printing directly on an envelope or onto a tape which is adhered to the envelope or package. Metering products are also used by package delivery services to signify expenditure of money for the package delivered. Most metering products can be thought of as including three basic components: a meter, a meter base and a scale. The meter typically includes a rotatable print head and the necessary electrical and mechanical components which set the print wheels carried by the print head, rotate the print head for each impression and account for the postage or other shipping charges. One conventional postage meter is disclosed in U.S. Patent Number 4,658,122 dated April 14, 1987, entitled POSTAGE METER STEPPER MOTOR MODULE, the disclosure of which is incorporated by reference. The meter itself is mounted to the meter base. The meter base provides the driving force for rotating the print head in the meter as well as providing the necessary structure for delivering letters past the print head during each print cycle. The scale may be mounted to the meter base or be a separate component from the meter base. The scale may be connected directly to the meter, which eliminates separate entry of postage amounts into the meter, or not, which requires the postage amounts to be separately entered. The present invention is directed to a meter base drive assembly used with meter bases, such as a postage meter base, to which a postage meter or other type of meter is mounted. The meter base typically includes a base frame to which an envelope drive and a print head drive are mounted. The meter base may also include a tape dispenser as well. A meter drive assembly defined according to the preamble of claim 1 is known from US 4 787 311. In this known assembly, the tension belt device actuates only one of the two drive belts. The aim of the invention is to provide a means for actuating both drive belts by means of one tension belt device. This problem is solved by the assembly according to claim 1. The design of metering products, such as postage meters, is a complicated, time consuming and thus expensive job. By using a single basic meter base which can be relatively easily modified to accomodate various other components, such as different types of meters, tape drives, letter feeders and so forth, economies in design and production can be realized. To do so, the drive assembly carried by the meter base must be inherently flexible to accomodate different driven components and various arrangements of the components. This is accomplished in a reliable, accurate and yet flexible manner through the use of the drive assembly discussed above to provide positive, accurate drive. Flexibility is achieved since to change the various driving speeds or drive ratios one needs merely to change the size of the driving or driven pulleys, an easily accomplished procedure. The motor drive, together with its associated drive pulley, are preferably pivotally mounted to the meter base frame to provide a clutched action in the event the load on the drive belt becomes too great. In addition to the override aspect of the pivotal mounting of the motor drive and drive pulley, the motor drive mounting platform can be spring biased to provide an adjustable tension on the first drive belt. The tensioning or loading of the first drive belt thus is a result of the weight of the motor drive, the torque exerted by the motor drive and the adjustable spring force on the mounting platform. The drive belts are preferably toothed drive belts which positively drive the driven pulleys. Other features and advantages will appear from the following description in which the preferred embodiments have been set forth in detail in conjunction with the accompanying drawings. Fig. 1 is a partial perspective view of a meter base showing a meter base drive assembly made according to the invention. Fig. 2 is a schematic side view of the meter base drive assembly of Fig. 1. Fig. 3 is a simplified schematic representation of the main drive elements of a meter base shown coupled to the driven pulleys in conjunction with portions of a print head shown in dashed lines. Fig. 4 is a partially exploded isometric view of a portion of an alternative embodiment of the meter base drive assembly of Fig. 2 in which the first and second pulley elements are positioned on a common shaft spaced apart from one another with the common shaft biased to provide a proper tension on the second drive belt. Referring now to Fig. 1, a meter base 2 is shown with its rear cover removed to illustrate the configuration of a meter base drive assembly 4 made according to the invention. Assembly 4 is shown to include a motor drive 6 which drives a drive pulley 8 (see Fig. 2) both of which are supported by a mounting platform 10. Platform 10 is pivotally supported by the frame 12 of meter base 2 at a pivot axis 14. Drive assembly 4 also includes a number of pulleys and belts coupled to drive pulley 8 so to drive the various components of meter base 2, as will be discussed below with additional reference to Fig. 3. Assembly 4 includes a first driven pulley 16, a second driven pulley 18, a dual pulley 20 and a pair of idler rollers 22, 24. A first, toothed drive belt 26 passes around drive pulley 8, second driven pulley 18, past idler roller 22, around a first pulley element 28 of dual pulley 20, past idler pulley 24 and back to drive pulley 8. Drive belt 26 is a dual sided, toothed belt having a first side 30 which engages complementarily toothed drive and driven pulleys 8 and 18. Second side 32 is also toothed and engages complementarily configured first pulley element 28. Pulley 16, 18, 22, 24 are all at fixed positions relative to frame 12 of meter base 2. Dual pulley 20 is mounted to one end of a pivot mount bar 34 which is connected to frame 12 at pivot 36. Tension is applied to first drive belt 26 in three ways. The weight of motor drive 6 pivots mounting platform 10 in the direction of arrow 38 (see Fig. 2); the reaction torque from motor drive 6 tends to pivot mounting platform 10 in the direction of arrow 38 as well. Finally, mounting platform 10 has an adjustable spring biasing force applied to it in the direction of arrow 38 by a tension adjuster 40. Tension adjuster 40 includes an adjustment screw 42 mounted to frame 12, and over which a spring 44 is mounted to press against mounting platform 10. The force of spring 44 on platform 10 is adjusted through an adjustment nut 46 to provide the user with a means for adjusting the tension on drive belt 26. While second driven pulley 18 is rotated in the direction of arrow 48, counterclockwise in Fig. 2, first pulley 16 is rotated in the direction of arrow 50, clockwise in Fig. 2, by a second, toothed drive belt 52 which passes around the first driven pulley 16 and a second pulley element 53 of dual pulley 20. This reverse rotation between first and second driven pulleys 16, 18 is achieved by driving second driven pulley 18 with first side 30 and first pulley element 28 of dual pulley 20 with second side 32. The tension on second drive belt 52, since dual pulley 20 is movably mounted to frame 12, is also determined by the biasing force applied to drive pulley 8. A third driven pulley 56 is coupled to a supplemental pulley 58 mounted integrally with and coaxially to second driven pulley 18 through a drive belt 60. The construction and operation of the various components driven by drive assembly 4 are conventional, are not a part of the invention and thus will not be described in detail. However, for a better understanding of the invention, various operating elements will be discussed in simplified form with reference to Figs. 1 and 3. First driven pulley 16 is seen to be operably coupled to an envelope drive 62 and a pressure roller 78. Envelope drive 62 includes, typically, a bump feed roller 64 and a pair of drive rollers 66, 68 on either side of an envelope sealer 70. An envelope 72 is driven through meter base 2 first through the operation of bump feed roller 64 which letter 72 then passes between an idler roller 74 and drive roller 66, past envelope sealer 70 and between idler roller 76 and drive roller 68. The envelope then continues past pressure roller 78 where an impression is made by a rotating print head 80. Print head 80 is driven by second driven pulley 18. Print head 80 is driven through the rotation of a print head drive shaft 82 and a print head drive gear 83. Gear 83 is driven by a meter drive gear 84 supported by frame 12. Note that print head 80, print head drive shaft 82 and print head drive gear, shown in phantom in Fig. 3, are part of a meter, not shown, which is mounted to meter base 2. Other types of mechanical drive connections between meter base 2 and the meter, instead of the use of meter drive gear 84, can be used as well. Different drive configurations are relatively easily accommodated by simply modifying the meter drive components downstream of second driven pulley 18. Third driven pulley 56 is coupled to and drives a tape dispenser 86, which dispenses tape segments when envelopes 72 are not being used for the impression. In some situations it is desirable to isolate first driven pulley 16 from envelope drive 62 and pressure roller 78 through a clutch 88 as shown in Fig. 4. This requires that first and second pulley elements 28, 53 be spaced apart from one another. In the embodiment of Fig. 4 this is accomplished through a drive spacer 90 having lugs 92 which engage corresponding slots 94 formed in pulley elements 28, 53, the combination being mounted on a shaft 96. Shaft 96 passes through and is supported within openings 98 formed in the laterally upstanding legs 100 of a generally U-shaped pivot support 102. Support 102 is supported by a pivot shaft 104 which passes through openings 106 in legs 100 and corresponding openings formed in a bulkhead 108 and an L-shaped support bracket 110. It is necessary to insure that sufficient tension is applied to second drive belt 52 to keep belt 26 from slipping. This is accomplished using a tension adjuster 112 including a J-bolt 114 hooked at its lower end to support bracket 110 and extending through a through hole 116 formed in the base 118 of U-shaped pivot support 102. Tension adjuster 112 includes a spring 120 which passes over threaded portion 122 of J-bolt 114 and is biased against base 118 by a nut and washer combination 124 mounted to threaded portion 122. Note that in the embodiment of Fig. 4 many of the elements shown in Fig. 1 are omitted for clarity. In use, drive assembly 4 has the various pulleys sized to accommodate the desired drive ratios for the components of the meter base 2 and the postage meter used. The postage meter is mounted to meter base 2 and is driven through meter drive gear 84. Adjustment of the tension on drive belts 26, 52 is achieved through tension adjuster 40 while in the embodiment of Fig. 4 the tension on second drive belt 52 can be further adjusted through tension adjuster 112. Rotation of the first, second and third driven pulleys 16, 18, 56 drive their respective envelope drive 62/pressure roller 78, print head 80 and tape dispenser 86 at the correct speeds and in the proper rotary directions. Modification and variation can be made to the disclosed embodiments without departing from the subject of the invention as defined in the following claims. For example, only first drive pulley 16 is driven in the opposite rotary direction as is drive pulley 8. If desired, more than one driven pulley could be so driven through the engagement of second side 32 of first drive belt 26.

Claims: A meter base drive assembly for use with meter bases having an envelope drive (62) and a print head drive (84), said meter base drive assembly comprising a motor drive (6), a drive pulley (8) driven by the motor drive, a first driven pulley (16) drivingly coupled to the envelope drive, a second driven pulley (18) drivingly coupled to the print head drive, a dual pulley (20) including first and second pulley elements (28,53), a first drive belt (26) engaging the drive pulley, the first pulley element (28) of the dual pulley and a selected one of the first or second driven pulleys, a second drive belt (52) engaging the dual pulley and the other of the first and second driven pulleys, and a belt tension device (40) for applying a tension to a drive belt, characterized in that said dual pulley has an axis movably mounted so that the tension applied by the belt tension device to the one of the first or second drive belts is also applied to the other of first and second drive belts. The assembly according to claim 1, wherein said dual pulley (20) is rotably mounted to one end of a pivot mount bar (34). The assembly according to claims 1 or 2, wherein said drive pulley (8) is mounted to and supported by the motor drive (6). The assembly according to claim 3, wherein said belt tension device comprises means (10) for pivotally mounting the motor drive (6) to a frame (12) of the machine for pivotal movement about a pivot axis (14) spaced apart from its output shaft, and means (40) for biasing the driven pulley (8) for biasing the motor drive and drive pulley therewith against the first drive belt (26). The assembly according to claim 4, wherein said biasing means includes an adjustable spring biasing mechanism (44). The assembly according to any one of claims 1 to 5, wherein said dual pulley (20) includes first and second pulley elements (28,53) spaced apart on a common shaft (96). The assembly according to any one of claims 1 to 6, further comprising a third driven pulley (56) drivingly coupled to a dispenser (86) and a third drive belt (52) engaging said third driven pulley and to a supplemental pulley (58) itself coupled to the second driven pulley (18).

Inventors: HENDRICKSON RICHARD, PAYN WARD, HENDRICKSON, RICHARD, PAYN, WARD
Applicants: NEOPOST IND, NEOPOST INDUSTRIE
Application year: 1990
Main classification: G07B17
IPC codes: G07B17