DE29903761U1 - knee pad - Google Patents

Description

Wilfried Augustin Zugspitzstrasse 13

D-82054 Sauedach

Tel. 08104-61300 Fax 08104-61301

knee pad

The invention relates to a knee pad for protecting the knee joints, e.g. during manual work, consisting of a thermoplastic outer shell and a soft, flexible foamed inner part.

Commercially available knee pads are made of polyurethane integral foam. These knee pads are molded foam parts, where the brackets for the fastening elements on the knee are usually separate inserts that are foamed in.

Originally, knee pads were made from CFC and HCFC blown polyurethane systems. This resulted in integral parts with a thick, wear-resistant outer skin and a light, foamed inner part. After the ban on CFC and HCFC as blowing agents for molded parts such as knee pads, water blown polyurethane foams were used. However, water-rubbed foams no longer have the thick, wear-resistant outer skin, but only a very thin, compacted edge zone. Commercially available knee pads are therefore not very wear-resistant, water-permeable and susceptible to the fastening elements tearing out due to the lack of an integral skin. The possibility of producing lighter parts has been exhausted for cost reasons and because of the amount of waste. If the weight is reduced further than the currently commercially available weight, the strength of the foam parts is no longer sufficient.

Due to the degradation of polyurethane through UV radiation, commercially available knee pads are colored black. Bright, fashionable colors or functional warning colors are not possible without additional painting of the molded parts.

The invention is therefore based on the object of providing a knee pad with a compact, wear-resistant outer skin and a light, soft and flexible, foamed inner part, whereby the outer skin is colored and light-stable and provides a secure hold for the fastening elements....

This is achieved according to the invention by a knee pad consisting of a preferably colored thermoplastic outer shell with a minimum density of 500 g/l, which preferably simultaneously forms the holder for the fastening elements, and a molded inner part made of soft, flexible foam with a density of 30-350 g/l.

The knee pad according to the invention achieves the following:

- The thermoplastic outer shell is more wear-resistant than the thin polyurethane outer layer of commercially available knee pads.

- The thermoplastic outer shell is waterproof and therefore increases comfort.

- The thermoplastic outer shell can be UV-resistant in any color, so that fashion trends or safety-related coloring can be taken into account.

- The brackets and/or holders for the fastening straps can be incorporated into the thermoplastic outer shell during the molding process, so that no additional parts are required.

- The thermoplastic outer shell can be used to hold the reaction mixture when foaming with polyurethane, saving mold release agents. -If a thermoplastic outer shell is used, a lighter foam can be used as the inner part of the knee pad. This makes it more comfortable to wear and reduces material costs.

An embodiment of the knee pad according to the invention is explained with reference to the drawing.
Show it:

Fig.1: Knee pads, top view, inside

1 = thermoplastic outer shell

2 = Bracket for fastening element
4 = soft foam

Fig.2: Knee pads, section A/B

1 = thermoplastic outer shell

2 = Bracket for fastening element

3 = Fastening strap

4 = soft foam

Fig.3: Knee pads, section C/D

1 = thermoplastic outer shell

2 = Bracket for fastening element
4 = soft foam

The knee pad according to the invention shown in Fig. 1-3 is exemplary.

The thermoplastic outer shell is preferably made of polyolefin, ABS or polyamide. It is also advantageous to use thermoplastic polyurethane (TPU) if the soft foam is also polyurethane. This ensures a uniform material class for disposal.

The soft foam preferably consists of molded polyurethane, so-called polyurethane soft foam. This soft foam is preferably foamed into the preformed thermoplastic outer shell using the reaction molding process.

However, other options include the use of polyolefin foam or ethylene vinyl acetate foam.

Claims (3)

1. Knee pad characterized in that it consists of a preferably colored thermoplastic outer shell with a minimum density of 500 g/l, which preferably simultaneously forms the holder for the fastening elements and a molded inner part made of soft, flexible foam with a density of 30-300 g/l. 2. Knee pad according to claim 1, characterized in that the foam is a polyurethane. 3. Knee pad according to claim 1, characterized in that the foam is a polyurethane reaction mixture foamed in the outer shell.