This invention pertains generally to the automatic labeling of produce items. Demand for labeling of produce items has increased significantly over the last several decades. As the demand has increased, it has become more important to increase the speed of the labeling machines. The top speed of prior art automatic labeling machines known to applicants is approximately 700 pieces of produce per lane per minute. Typical labeling systems in commercial packhouses utilize 8 to 10 lanes.
Along with the demand for higher labeling speeds, the produce owners have demanded that labeling machines be capable of applying labels of different sizes. To apply labels of different sizes, time consuming changes typically have to be made in the drive mechanism for rotary heads and/or label cassettes. These changes not only take considerable amounts of time, but typically require costly downtime of the rotary drive and require that the user have the appropriate parts necessary to adapt the rotary head drive mechanism and/or the label cassette to a different label size.
The prior art has provided various designs and techniques to increase labeling speed. The Anderson et al U.S. Pat. No. 6,047,755 (the '755 patent) is the closest prior art known to applicants. The '755 patent teaches the use of a single stepper motor for driving two direct drive gear trains; a first gear train driving the rotary head and a second gear train driving the cassette label carrier strip. We have found that the direct gear drive of the '755 patent creates an inherent limitation in the speed at which the label carrier strip can be reliably advanced by the stepwise, rotational speed imparted to the carrier strip by the stepper motor. We have found that at labeling speeds above 700 labels per minute, the label carrier strip either tears or otherwise fails as the stepper motor indexes, or steps, and jerks the label carrier strip. As described below, the present invention has overcome this limitation of the prior art.
One prior art technique for adapting the labeling machine to apply different size labels is taught by the Anderson et al '755 patent noted above. As shown in
Accordingly, there is a significant and growing demand for labeling machines capable of both higher speed and a “quick-change” capability for applying labels of different sizes.
The present invention accomplishes both of the above stated goals. It provides a labeling speed of approximately 1,000 labels per minute for a given lane, a quantum increase of over 40% greater speed than labelers known to applicants. The invention also provides a “quick-change” system which significantly reduces the time necessary to adapt the labeler to a different size label.
As shown and described below, the present labeler provides a “Geneva” wheel assembly in the drive mechanism for the label carrier strip. The “Geneva” wheel assembly reduces the jerk applied to the label carrier strip as the stepper motor steps or indexes, and then provides a momentary “boost” or acceleration of the label carrier strip, increasing the label dispense speed for a portion of the label dispense cycle while maintaining the timing of the label dispensing. As described below, we have found that the jerk applied to the label carrier strip is the primary reason that the prior art '755 patent mechanism either tears the label carrier strip or allows slippage of the label carrier strip at speeds above 700 labels per minute. The labeling prior art includes a Geneva movement in U.S. Pat. No. 2,528,856, but the present invention utilizes a Geneva wheel assembly in a substantially different way than that prior art.
With respect to using labels of different sizes, the prior art typically requires a modification to the rotary head drive. The present invention eliminates the need to change or adjust parts in the rotary head drive mechanism, which requires labeling down time and often takes considerable time. The present invention allows the operator to simply change a pulley wheel and belt in the label cassette and adjust a scallop wheel in the label cassette. This can be done in a fraction of the time required by known labelers. For example, in a typical packhouse with an 8 or 10 lane prior art labeling system, in order to change all 8 or 10 lanes to apply different size labels, a downtime of all 8 or 10 lanes of about 8 to 10 hours would be typically required. Using the present invention, all 8 or 10 lanes can be converted in about 10 to 15 minutes, only about 3% of the time required in prior art systems. Labeling machine downtime often results in large amounts of produce being downgraded. A labeling system with 8 lanes is capable of labeling about 336,000 produce items per hour, or about 2,500,000 produce items in an 8 hour shift, if running at full capacity. Reducing labeling machine down time prevents such economic losses.
The present invention also provides an improved cassette label carrier strip tensioning mechanism which helps to facilitate a labeling speed of about 1,000 labels per minute per lane. The improved tensioning system helps to prevent the label carrier strip from slipping or tearing, either of which can cause costly down time of the labeler. The improved mechanism holds the label carrier strip against a scallop pulley more firmly and over a larger arc of the scallop pulley circumference, reduces inertia of the tensioning mechanism and reduces unwanted jerking of the label carrier strip.
The present invention provides a system that has the same floor footprint of prior art systems, allowing the new system to be installed in the same location, using the same floor space as prior art systems.
The present invention also eliminates a cam typically used in known labeling systems for lifting the stripper plate each time a label is transferred from the label strip to the tip of a bellow. This feature further reduces the number of moving parts in the label drive. A typical known stripper plate is shown and described in La Mers U.S. Pat. No. 4,217,164.
A primary object of the invention is to provide an automatic produce labeling machine capable of applying 1,000 labels per minute per lane, while minimizing slippage and tearing of the label carrier strip by substantially reducing jerk imparted to the label carrier strip.
Another object is to provide a “quick change” feature to the labeling system allowing the use of different size labels, wherein the label cassette may be opened and parts changed in a few minutes, all without having to stop operation of the rotary head.
A further object is to provide an improved tensioning system that helps minimize tearing or slipping of the label carrier strip.
A further object is to eliminate a cam utilized to cause oscillation of the tip of the label stripping plate by replacing said cam with an adjustable set screw which allows motion of the tip of the stripping plate.
Further objects and advantages will become apparent from the drawings and the following description.
The invention may be used on any standard type labeling machine used in the produce labeling industry for automatically applying adhesive labels to produce, such as the standard Sinclair RM6 (as shown and described in La Mers U.S. Pat. Nos. 4,217,164; 4,303,461; 4,454,180; 4,547,252; and Briggs et al U.S. Pat. No.4,896,793, all of which are incorporated by reference as though set forth in full) or SPRM6 labeling system. The RM6 labeling system is used in the conventional way to apply labels to produce. The Sinclair model RM6 machine is commercially available from Sinclair Systems International, LLC, 3115 South Willow Avenue, Fresno, Calif. 93725.
Geneva wheel assembly 200 includes a Geneva input wheel 210 and Geneva output wheel 220. Input wheel 210 has 80 teeth (not shown for clarity) around its perimeter 211. Input wheel 210 carries a pair of Geneva drive pins 215, 216 which pins are positioned 180° from each other. Input wheel 210 rotates in a counterclockwise direction as viewed in
Output wheel 220 carries a cassette drive pulley 230. Drive pulley 230 has 16 teeth (not shown for clarity). A belt 240 transfers rotary drive power from Geneva output wheel 220 to a cassette scallop pulley 250. Scallop pulley 250 is a “quick change” pulley to adapt the cassette drive mechanism to apply different sized labels, as shown and described further below. Scallop pulley 250 is carried by shaft 255 (
As shown in
As shown in
The dashed line 250 illustrates the speed imparted to the label drive, and to the label carrier strip, by a prior art system (such as shown by the '775 patent) without the present invention during a single cycle of about 17 milliseconds (1,000 labels per minute), wherein the prior art system is attempting to achieve a labeling speed of 1,000 labels per minute per lane. In the first 1-3 milliseconds, the rotational speed increases from zero to about one foot per second by a stepper motor drive such as in the '755 patent, and remains constant until the last few milliseconds, when it drops back to zero. The significant aspect of line 250 is the large acceleration, or “jerk,” early in the cycle, shown as 251. This large acceleration causes tearing and/or slipping of the label carrier strip.
Line 260 illustrates the speed imparted to the label drive, and to the label carrier strip, by the Geneva wheel assembly 200 of the present invention during each step of the stepper motor, wherein the label carrier strip is advanced the length of a label, constituting a label dispense cycle. The labels are transferred to the bellows of the rotary head as known in the art. A much lower acceleration is imparted in the first several milliseconds of the cycle, shown as 261, significantly reducing the amount of jerk applied to the label carrier strip. The reduced initial acceleration or jerk, shown as 261, as the stepper motor “steps,” is substantially reduced and believed to be more than 40% less than the jerk 251 imparted to the label carrier strip 320 in the absence of the present, improved Geneva drive assembly. The present invention minimizes the jerk imparted to the label carrier strip 320 as the stepper motor steps, or indexes. The speed shown by line 260 rises with rapid acceleration during the next portion of the cycle to roughly twice the speed of line 250, which compensates for the lower speed achieved by line 260 early in the cycle. The Geneva wheel assembly, in effect, greatly reduces jerk imparted to the label carrier strip early in each cycle, but achieves greater acceleration and rotational speed in mid-cycle, to achieve greater overall labeling speeds.
As shown in
As shown in
We believe the jerk of the label carrier strip with the present system is reduced at least 40 percent compared to known produce labelers of Sinclair Systems International, LLC, and compared to the system of U.S. Pat. No. 6,047,755.
As shown in
The pulley and scallop wheel replacement can be done in a matter of minutes prior to placing the cassette on the applicator, reducing down time of the applicator.
As tension is applied to label carrier strip 320, the nip roller 340 and tension roller 330 move, in a counter-clockwise direction to the positions shown in phantom as 340′ and 330′. As the nip roller 340 and tension roller move to the phantom positions, the amount of frictional contact between label carrier strip 320 and the surface of scallop wheel 310 drops from about 260 degrees to about 200 degrees of the scallop wheel circumference. This motion of nip roller 340 and tension roller 330, when driven by a prior art drive system at speeds of about 1,000 feet per minute causes a jerking of the label carrier strip that can tear the strip and/or cause slippage of the strip on the surface of scallop wheel 310. Both of the scenarios almost always cause extensive labeling down time.
The improved tensioning system of
Motor gear 720 drives an idler gear 730. Idler gear 730 has 48 teeth (not shown) and rotates clockwise as shown by arrow 731.
Idler gear 730 drives output gear 740, which in the preferred embodiment has 72 teeth (not shown) and rotates counterclockwise, as shown by arrow 741. Output gear 740 drives the rotary head (not shown).
The diameter of the bellows is preferably reduced, in order to reduce the volume of air needed to extend each bellow, facilitating increased labeling speed. The cross-sectional diameter of a retracted bellow is reduced by approximately 25% from a diameter of about 60 mm to a preferred diameter of between 40 mm and 50 mm.
The foregoing description of the invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications and variations are possible in light of the above teaching. The embodiments were chosen and described to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best use the invention in various embodiments and with various modifications suited to the particular use contemplated.
This application claims the benefit of and priority from U.S. provisional application Ser. No. 62/043,748 filed Aug. 29, 2014.