Plastic pallet with sleeved reinforcing rods and associated method for making the same

Plastic pallet with pinch pin and associated manufacturing method.

Field of the invention

The present invention relates to the field of the usual pallets in material handling, and more particularly to a multi-piece plastic pallet designed for use with forklift equipment.

Background of the invention

Pallets are commonly used to transport and store goods. A pallet typically includes an upper platform and a lower platform separated by support blocks. Traditionally the pallets have been built of wood. While they are advantageous in terms of costs, wooden pallets have many disadvantages. For example, they are subject to breakage and therefore can be reused for a short period of time. Wooden pallets are difficult to maintain in a sanitary condition, and therefore their use is limited in applications where healthy transport is important, such as food transport applications.

With the growth of the plastics industry, a wide variety of plastics has been investigated to determine the appropriateness of its use for the production of pallets. Plastic pallets are easily moldable and are stronger and lighter in weight than wooden pallets. They can be made with recyclable material. In addition, plastic pallets have longer life than wooden pallets.

In terms of duration, plastic pallets repeatedly come into contact with the sharp metal bars of a fork lift, which is also called a pallet jack. The support blocks that separate the upper and lower platforms are subject to more intense wear than any other part of the pallet. Additionally, if the pallet jack bars are introduced very far between the upper and lower platforms so that the pallet jack wheels remain resting on the lower platform then the upper platform is separated from the lower platform when the bars of the pallet are raised. pallet jack The resulting damage when the upper platform is separated from the lower platform requires replacing the upper platform, and if the damage is very extensive then the entire pallet is replaced.

If only the support blocks are damaged by the pallet jack, then they can be replaced at a much lower cost than replacing the entire pallet. For example, document nr. US 5,413,052 describes a plastic pallet having an upper platform and a lower platform with replaceable support blocks between them. The support blocks include octagonal posts that have support wall members located under reinforced portions of the upper platform. The posts also have a sleeve with a central pin hole parallel to the support wall members. The lower platform receives the support blocks in lowered seats. The plastic pins are inserted through the upper platform, each post and the lower platform. To hold the pins in position, plastic T-nuts are used.

In document nr. US 4,843,946 a plastic pallet includes identical upper and lower platform interconnected by support blocks. Each support block includes a central core and a bushing that interconnects it by radio. The core has flexible tabs that extend beyond the opposite ends of the bushing and are locked in the base and load layers. The plastic pallet described in US 5,791,261 also describes the use of flexible tongues to hold the base and load layers together. In particular, the plastic pallet comprises support blocks between the upper and lower platforms and interlocking elements at upper and lower pressure extending from the respective upper and lower platform through the support blocks to interlock with each other. US-A-6 021 721 describes a pallet with a snap closure where the upper and lower platform are connected by spacer blocks 14 with spike members 42.43.

While plastic pallets offer several advantages over wooden pallets, there is still a demand to increase the durability and resistance of plastic parents

Summary of the invention

In view of the foregoing background, an object of the present invention is to reduce or limit the damage caused to the plastic pallets by a fork lift and other lifting devices.

This and other objects, advantages and properties according to the present invention are present in a plastic pallet according to claim 1.

Each support block can include rounded edges. Each pressure grip pin may comprise a head to fit into an opening of the pressure grip pin and separate tips extending through the receiving cavity of the pressure grip pin to engage in a rear portion of the inner bushing associated with he.

An advantage of the pinch pins is that they can act as fusible links in the event that excessive separation force is applied between the upper and lower platforms. This force of separation can occur when the wheels of the verbal Jack rest on the lower platform, and the bars that extend from Father's Day are pushed up. This is the cause of the upper platform becoming separated from the lower platform. In the support blocks the tabs on the fusible links will fit or break when the separation force becomes excessive. As a consequence, instead of replacing the entire upper platform, agave pins with broken tabs will be replaced.

Each press grip pin can further comprise a body coupled between the head and the separate tips. The separated tips can extend elastically outward of the body after having passed through the cavity that receives the pinch pin to engage the rear face of the inner sleeve associated therewith.

The separate tips of each pressure grip pin may be angled to facilitate insertion thereof through the cavity that receives the pressure grip pin. The separate tips of each press grip pin comprise a respective lip for engaging in the rear face of the inner sleeve. The respective lips of each pressure grip pin may be configured to break based on a separation force applied between the upper and lower platforms.

Each second connecting member may further comprise ribs that extend between the inner bushing and the receiving cavity of the pinch pin located within it. The ribs can extend radially along a length of the inner bushing and along a length of the receiving cavity of the snap pin. As a consequence, an advantage of the support blocks is that the impact energy when making contact with the bars of the lifting equipment can be dissipated between the following elements: the inner bushing, the outer bushing, the radial ribs and the cylindrical core defined by the receiving cavity of the pinch pin in the inner bushing. The lifting bars impact firstly against the outer bushing, which absorbs most of the impact energy. The impact energy can then be transmitted to the inner sleeve which also absorbs some of the impact force. The greatest absorption of the impact force takes place in the radial ribs. The remaining impact energy then reaches the receiving cavity of the pressure grip pin to dissipate.

Another aspect is directed to a method for making plastic pallets such as those described above and a method such as that described in claim 13. The pressure grip pins may be inserted into pressure grip pin openings in the upper platform. Each pressure grip pin may comprise a head for engaging in a pressure grip pin opening and separate tips that extend through the receiving cavity of the snap grip pin for engaging in a rear portion of the inner bushing associated with he.

Brief description of the drawings

Figure 1 is a top perspective view of a pallet assembled in accordance with the present invention;

Figure 2 is a bottom perspective view of the pallet shown in Figure 1;

Figure 3 is a bottom perspective view of the upper pallet platform shown in Figure 1;

Figure 4 is a top perspective view of the lower pallet platform shown in Figure 1;

Figure 5 is a perspective view of a pressure grip past used in conjunction with each support block according to the present invention;

Figure 6 is a top view of the pinch pin shown in Figure 5;

Figure 7 is a partially sectioned side view of a pallet illustrating a pressure grip pin together with support blocks according to the present invention.

Detailed descriptions of preferred settings

The present invention will now be described in more detail below with reference to the accompanying drawings, in which preferred configurations of the invention are shown. However, this invention can be configured in many different ways, and should not be constructed as limited to the configurations set forth therein. On the contrary, these configurations are presented so that the description will be clear and complete and will lead completely within the scope of the invention to those skilled in the art. Equal numbers refer to equal elements throughout it

Figures 1-4 illustrate top and bottom perspective views of a pallet 10 having upper and lower platforms 12, 14 that are held together using snap-on pins 16. The upper platform 12 is also known as the loading layer and the lower platform 14 is also known as the base layer.

The upper platform 12 includes multiple first joint members extending downwardly from the upper platform, including with each first joint member an outer sleeve 40. The lower platform 14 includes multiple second joint members extending upwardly from the platform bottom, including with each second connecting member an inner sleeve 42. The inner bushing 42 of the second connecting members receives the outer bushing 40 of the first joining members to define support blocks 18, 18a joining the upper and lower platforms 12, 14.

The support blocks 18, 18a define a space 20 between the upper and the lower platform 12, 14 to receive at least one lifting member, such as a bar of a pallet jack. An advantage of the pressurized pressure pin 16 is that they act as fusible links in the event that a separation force is applied between the upper and lower platforms 12, 14 of the pallet 10. This separation force can occur when the wheels of the pallet jack rest on the lower layer 14 and the bars extending from the pallet jack are raised upwards. This is the reason that the upper platform 12 becomes separated from the support blocks 18, 18a. The tab 50 on the fuse links 16 will crack or break when the separation force is too excessive. As a consequence, instead of replacing the entire upper platform 12, the pressurized snap pins 16 with the broken tongues 50 will be replaced.

As will be discussed in great detail below, the support blocks 18,18a are formed by the outer and inner bushes 40, 42, which extend from the respective upper and lower platforms 12, 14. The outer and inner bushes 40, 42 , are molded as part of their respective upper and lower platforms 12, 14. However the upper and lower platforms 12,14 are molded separately.

The upper platform 12 comprises a flat surface, generally smooth, having multiple holes 22 extending therethrough.

Similarly, the lower platform 11 comprises a flat, generally smooth surface, which has multiple holes 23 extending therethrough.

The holes 22, 23 provide several benefits, including a reduced surface area of ​​the upper and lower platforms 12, 14, greater air circulation for the items located on the upper platform and a lower panel weight, for example. An example of a plastic pallet with upper and lower platforms is described in the patent application published in the USA under the number 2007/0256609. This patent is assigned as the current assignment of the present invention and is incorporated herein in its entirety by reference.

The upper platform 12 may include an outer perimeter 24 of the planar surface that has no holes. This area can be about 75-125 mm wide, for example. The lower platform 14 has a perimeter shape that substantially fits the perimeter shape of the upper platform 12. The lower platform 14 may include a rectangular perimeter shape having cross members 26, 28 intersecting a central portion of each side of the rectangular perimeter, halfway between the corners of the pallet.

The upper and lower platforms 12, 14 can be molded from thermoplastics or other polymeric materials, including high density polyethylene (HDPE), polypropylene (PP), among other polymeric materials. As can be appreciated by those skilled in the art, polymeric materials may be filled or unfilled and / or may include particles of fibrous material, natural or synthetic, among other properties. For example, the unfilled HDPE can provide improved impact resistance, the PP having reinforcers (for example, long glass fibers) can provide improved structural properties, and the unfilled PP with random copolymers can provide enhanced reinforcing qualities.

The upper and lower platforms 12, 14 can be molded of different thermoplastics or other polymer materials. For example, the upper platform 12 may be molded from a first type of a thermoplastic or polymer material, while the lower platform 14 may be molded from a second type of thermoplastic

or polymer material. According to preferred configurations, all or a portion of the upper and lower platforms 12,14 may be constructed of materials other than plastic such as wood and / or metal, for example.

The illustrated pallet 10 has a substantially square shape. An example of pallet size 10 is 1224 mm by 1224 mm, for example. As those skilled in the art can appreciate at the time, pallet 10 may be constructed of other rectangular shapes, such as 1020 mm by 1224 mm, for example. The pallet 10 may include rounded corners / edges 30 along the perimeter. Rounded corners / edges 30 can help reduce and / or eliminate damage during impact with the bars of a fork lift, as well as providing an improved aesthetic appearance.

The illustrated pallet 10 includes numerous support blocks 18, 18a, which have been provided to provide the joint between the upper and lower platforms 12, 14, as well as providing separation so that the bars of a pallet jack can be inserted in between. For example, the pallet 10 includes 9 support blocks 18, 18a that are located at the corners of the pallet as well as between the corners of the pallet along the outer edges of the pallet. A support block 18a is also provided in the center of the pallet 10 at the intersection of the cross members 26, 28 on the lower platform 14.

Each support block 18, 18a is defined by an outer bushing 40 extending downwardly from the upper platform 12 and by an inner bushing 42 extending upwardly from the lower platform 14. The upper and lower bushes 40, 42 are they mold together with their respective upper and lower platforms 12, 14. The upper and lower bushings 40, 42, are sized so that they overlap with each other when joined together. The shape of the outer and inner bushings 40, 42 may be square shape, triangular shape, oval shape or cross shape, for example. The edges of the outer bushes 40 can be rounded.

The upper platform 12 includes multiple openings for pinch pins to receive the pinch pin 16. Each outer bushing 40 surrounds its respective snap pin opening. The lower platform 14 includes a receiving cavity 44 of a pressure grip pin each located inside the lower bushing 42. Multiple radial ribs 43 extend between the pressure grip pin receiving cavity 44 and the inner sleeve 42.

An advantage of the support blocks 18, 18a is that the impact energy of the contact with the forklift bars can be dissipated between the following elements: the outer bushing 40, the inner bushing 42, the radial ribs 43 and the core defined by the receiving cavity 44 of the pinch pin in the inner bushing. The fork bars strike first against the outer bushing 40, which absorbs most of the impact energy. The impact energy can then be transmitted to the inner sleeve 42 which absorbs some of the impact energy. The greatest absorption of the impact energy takes place in the radial ribs 43. The remaining impact energy reaches the receiving cavity 44 of the pressurized pin for dissipation.

Each pressure grip pin 16 includes a head 46, a body 48 and separate tips 50, as best illustrated in Figure 5. The head 46 is for engaging in an opening of the pressure grip pin on the upper platform 12. The head 46 of the pressure grip pin 16 must be shaped to include separate straight edges 49, as illustrated in Figure 6. Each opening of the pinch pin in the upper platform 12 is shaped in the same corresponding manner. This helps keep the pressure-grip pins 16 in position. The pressurized snap pins 16 are typically inserted in the pallet 10 after the upper and lower platforms 12, 14 have been joined to form the support blocks 18, 18a.

The separated tips 50 extend through the receiving cavity 44 of the pressurized grip pins to grip the rear face 60 of the inner bushing, as best illustrated in Figure 7. The receiving cavity 44 of the grip pins Pressurized pressure does not extend all the way from the upper part of the inner sleeve 42 to the lower part of the lower platform 14. This is to allow space for the tabs 50 in the pressure grip pin 16 to release and grab the rear face 60 of the inner sleeve 42.

Even though the upper and lower platforms 12.14 are separated in Figures 3, 4, the pressurized pinch pins 16 are positioned in accordance with the purposes of the illustration. As illustrated in Figure 3, the pinch pins 16 extend inside and beyond the outer bushes 40. As illustrated in FIG. 4, the heads 46 of the pressure-grip pins 16 appear above the inner sleeve 42 and the receiving cavities 44 of the pressure-grip pin when the lower platform 14 is not in place. This allows slack for the head 46 of each pressure grip pin 16 to engage in a pressure grip pin opening in the upper platform 12, while the separated tips 50 extend through the receiving cavity 44 of the pin Press grip to grip a rear face 60 of the inner sleeve 42 associated therewith.

The separated tips 50 of each pressurized pin 16 extend elastically from the outside of the body 48 after having passed through the receiving cavity 44 of the pressurized pin to grip the rear face 60 of the inner sleeve 42 associated with she. The separate tips 50 of each pressure grip pin 16 may be angled to facilitate insertion thereof through the receiving cavity 44 of the pressure grip pin. The separate tips 50 of each press grip pin comprise a lip 51 for gripping the rear face of the inner sleeve. The respective lips 51 are configured to break in case of an excessive separation force applied between the upper and lower platforms 12, 14. The pressure grip pins 16 are also made of plastic. Alternatively, the pinch pins 16 may be made of any material used to form the upper and lower platforms 12, 14 as described in detail above.

Another aspect is directed to a method for manufacturing a pallet 10 as described above. The method comprises placing the inner bushings 42 of the multiple second joint members to receive the outer bushings 40 of the multiple first joint members to define multiple support blocks 18,18a that join the upper and lower platforms 12, 14 . Multiple grip pins 16 are inserted into the multiple pressure grip pin openings in the upper platform 12. Each press grip pin 16 comprises a head 46 for engaging in an opening 44 of snap grip pin and separate tips 50 which extend through the pressurized pin receiving cavity 44 to grip the rear face 60 of the inner sleeve 42 associated therewith.

Many modifications and other configurations of the invention will come to the head of those skilled in the art from the benefits of the teachings presented in the above description and associated drawings. However, it should be understood that the invention is not limited by the specific configurations described and that the modifications and configurations must be thought of as included, as described in the appendix claims, as well as those understood in the art will really appreciate.