Screws, Timing

Timing Screws, info

To keep your packaging line running smoothly and safely at peak efficiency, split second timing and accuracy in containing handling is critical.

The major function of any timing screw is to provide the smooth flow of containers into or between packaging machines, but today's highly sophisticated timing screws can do more than just feed containers into the packaging machine.

Using different design variations, the timing screw can halt or position containers for packaging operations and can serve as a line-control device. They can also accelerate, decelerate, divide or combine the container flow. The key to peak performance is dependent on the precise "form fit" between the container and timing screw.

To provide direct insight into timing screw specification, let us examine some of the more widely used timing screw configurations and discuss their specific packaging purposes.

Straight-Root Designs

The basic straight-root design (Figures 1-4) is formed when the lines of the inside diameter are parallel to the shaft.

In the common form of this design, thread height is gradually increased to the outside diameter to create a smooth container infeed. Variations on this and other screw designs, numbers and placement, enable timing screws to divide and merge containers. They can accelerate, decelerate or even stop the motion of containers for special packaging operations.

Inverse-taper-infeed: This configuration accepts randomly fed containers more readily than the straight-root design and is also more effective in separating square containers, a design in which the initial pocket of the screw is formed at the maximum outside diameter, then it tapers gradually to the root diameter.

Transfer (Figure 1): Particularly useful on high speed lines, this screw accepts containers at the discharge end of one machine and positively controls the container to the infeed of the next machine. This prevents container contact, thus eliminating scratching and spillage of the contents. The pitch of the screw can remain the same of be varied as called for by the machine pitch requirements.

Figure 1. Transfer

180-degree discharge (Figure 2): Known as the dual-flight, or double-lead screw, this design will maximize container output by means of two threads cut into the screw. These threads discharge containers every 180° of rotation instead of the normal 360° standard. This effectively doubles the output. Use for this screw is limited, however, since not all packaging machines are capable of functioning with this timing arrangement.

Figure 2. 180 Degree Discharge

Multiple dwell (Figure 3): This screw design, known as stop-position, can stop a container one or more times to perform different functions. The screw has a vertical section in the screw pitch that momentarily halts the container in its forward motion. It is useful for such actions as banding, sleeving, labeling, cottoning, leaflet placement, in-line filling, closing, plugging operations.

Screw design can vary the number of dwells and the degree of dwell time over wide limits to suit packaging requirements.

Figure 3. Multiple Dwell

Grouping (Figure 4): When multiple containers must be collated into a grouping, this design performs the operation smoothly by picking up two or more containers in a single pocket and then spacing the collation by a full pitch from the next group. This group of containers can them be discharged closely spaced to enable banding or overwrapping of needed.

Figure 4. Grouping

Custom Timing Screws

Turn-A-Round Screws: have revolutionized the timing screw world and because of this, Ernst has answered this call by making sure we can produce the smoothest running screws on the market. Ernst has been making Turn-A-Round Screws for 30 years, long before the competition even cut their first Straight Root Screw. Turn-A-Round Screws can be cut to discharge on any degree needed (45° , 90° ,210° etc.). All T.A.R. Screws can be run on Ernst Drive Systems.

Orienting (Figure 5): This requires a custom-designed shape to enable precise positioning of oddly shaped containers that could normally travel in two positions but, with this screw design, can be made to travel with either a point or a flat surface facing the screw.

Figure 5. Orienting

Twisting: Usually performed on found containers to accomplish air cleaning, bottle washing, bottom coding, labeling or cartooning. Using specially shaped guide rails in conjunction with the timing screw, a vertical container can be twisted from an upright position with the opening at the top to an inverted position with the opening at the bottom. A container can be taken from a vertical to a horizontal position to run from along side to on top of the timing screw.

Turning (Figure 8): This configuration utilizes a pair of equal length of staggered length screws also known as rotational orienting or turn-around designs. They can orient containers in any required axial position between 0° and 360°.

Used for turning of containers in group fillers to occupy less space, this design enables filling spouts to be grouped on shorter centers. This same action can be used to assist in labeling operations. It can also turn containers between such operations as primary labeling and the attachment of secondary labels of literature.

Figure 8. Turning

Body and neck stabilizing: Timing screws can be mounted one above the other to increase the stability of tall and unstable bottles, particularly those with multiple cross sections such as a square body with a round neck.

For example, using a larger screw on the bottom and a smaller screw in the cap or neck area, both screws are kept running uniformly in pitch. Where the control of the tall, unstable container becomes even more critical is in such functions as labeling, coding and video inspection.

Shingling (Figure 9):This function is performed by a pair of screws of different lengths with equal infeeds, that will offset a square or rectangular container.

Because of their sharp corners and little or no radius, square of rectangular containers must first be offset to enable a thread form to better separate, accelerate and control this type of container.

Figure 9. Shingling

Form fitting (Figures 11,12 and 13): Form fitting the timing screw to the container is especially helpful in controlling oval, elliptical and tear-shaped containers at faster operating speeds. For example, Ernst Timing Screws makes timing screws which can be cut to match the contour of the containers, no matter what the shape or size.

Figure 11. In a form fit timing screw the sam container remains stable.

Figure 12. Unusual container shapes require form fitting timing screws for proper handling

Figure 13. Non-form fitting timing screws allow for unwanted container play

Multiple Systems - Combining & Dividing

Combining (Figure 6): A particularly useful design when the output of two lines is needed to be made into one. Some examples are when two unscramblers are needed to supply a single packaging line, the merging of two products into combination packages or the merging of two lines into one or more packaging operations. This design is accomplished by pairing two screws of the same configuration, allowing two lines of containers to be merged into one.

While these two screws are identical, their axial positions are 180° apart, thus enabling alternate container feeds from two different converging lines.

Figure 6. Combining

Dividing (Figures 7 and 10): One of the most functional designs, this pair of timing screws can evenly distribute a single line of containers into multiple lanes. This screw configuration can also divide a supply of containers between machines of lesser capabilities. For example, a multiple case packing operation requiring a single line can be divided at high speeds into multiple lanes.

Figure 7. Dividing

Ernst timing screws