Two-circuit grip heater

Abstract

A grip heater has a tubular insulator that is designed to slip over a handlebar and has two interposed pairs of helical recesses. Each pair of helical recesses is formed by two parallel helical grooves and accommodates a heating element; the heating elements can have different resistances to provide differing degrees of heat when selectively connected to a voltage source. Preferably, the pairs of recesses overlap such that the heating elements reside in alternating grooves and cross over each other. The heating elements can be connected to a common ground to allow replacement of existing three-wire grip heaters. When a common ground is employed, the heating elements are preferably isolated where they cross.

Description

BACKGROUND OF THE INVENTION [0001] Grip heaters are employed to heat the hand grips of motorcycles, snowmobiles, and similar equipment which are operated in cold weather but which require sufficient dexterity on the part of the user to make the wearing of bulky mittens or gloves impractical. Such grip heaters are particularly beneficial in alleviating the effect of wind chill, especially when used on vehicle handgrips. These grip heaters have an electrical heating element which is embedded in the handgrip and is powered by a voltage supply of the equipment, such as a battery or a magneto. Examples of such grip heaters are taught in U.S. Pat. Nos. 4,471,209; 4,937,429; and 4,990,753 of the present inventor. These grip heaters have a single heating element of resistive wire wrapped over a tubular insulator having a pair of helical recesses in which the heating element resides. This structure is subsequently covered with a soft grippable material such as rubber to form a composite grip...

AI Technical Summary

Benefits of technology

[0014] To simplify the circuitry and to provide a grip which is suitable to retrofit many of the conventional circuits in service, it is preferred for the heating elements to be connected together at their unswitched ends to provide a common ground. As discussed above, if such is done, it is

Problems solved by technology

Grip heaters are employed to heat the hand grips of motorcycles, snowmobiles, and similar equipment which are operated in cold weather but which require sufficient dexterity on the part of the user to make the wearing of bulky mittens or gloves impractical.

The printed circuits maintain reasonable grip thickness since the conductors are thin and flat; however, these conductors tend to break down at one or more locations along the conduction during use.

These breakdowns may result from damage to the printed circuits due, in part, to mechanical straining of the circuit by the user applying force or torque to the grip to maneuver the device to which it is attached.

The mechanical strains introduce irregularities which in turn causes the temperature to spike, causing local deterioration of the circuit and ultimately failure; this limits the useful life of such devices.

Two additional problems that have been found in printed circuit grip heaters are delamination and heat loss.

Over time, the circuit substrate delaminates from the underlying structure, apparently due to thermal degradation of the laminating adhesive, again reducing the life of

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