The invention relates to an electrical appliance having a battery holder, which battery holder has a housing which can accommodate at least one battery and which battery holder can be inserted into a housing of the electrical appliance, locking means being provided for locking the battery holder in the appliance.
Such removable battery holders, also referred to as power packs, are used, for example, in electrically chargeable appliances such as drills. An example of this is described in DE-A1-39 02 442. The construction for locking such battery holders in the electrical appliance often comprises a large number of parts, which are usually made of a plastic.
It is an object of the invention to provide a removable battery holder for an electrical appliance, which holder has a comparatively small number of parts for locking the battery holder and which has a locking mechanism which is reliable, also in the long run.
To this end, the appliance in accordance with the invention is characterized in that the locking means are formed by two spaced-apart resilient plastic fingers which each have a projection and by at least one boss for cooperation with the projections of the resilient fingers which fingers and boss have been provided, respectively, on the housing of the battery holder and on the housing of the appliance or the other way around, and which resilient plastic fingers are supported, in the direction of their resilient action, by resilient limbs of a material having a stiffness greater than the stiffness of the resilient plastic fingers. The plastic fingers and the boss can simply be molded integrally with the housing of the battery holder and with the housing of the appliance, respectively. When the battery holder is fitted into the appliance the boss slides between the resilient fingers, upon which the projections are moved apart and subsequently come together after passage of the boss. The resilient limbs whose stiffness is greater than that of the fingers back up the resilient action of the plastic fingers, as a result of which a reliable operation and locking of the battery holder is achieved. To remove the battery holder from the appliance no release button as in DE-A1-39 02 442 is needed. Moving plastic parts are frequently subject to creep. Creep gives rise to a reduction of the force with which the battery holder is locked in the appliance. The resilient limbs prevent the locking mechanism from being adversely affected by creep. The resilient limbs form an additional part but they prolong the life of the mechanism significantly. Moreover, the resilient limbs have an additional advantage, as will be explained hereinafter.
Preferably, the material of the resilient limbs is an electrically conductive metal.
A preferred embodiment is characterized in that the housing on which the boss has been provided has electrically conductive limbs which upon insertion of the battery holder into the electrical appliance automatically make contact with the resilient metal limbs which serve for supporting the resilient plastic fingers. The metal limbs make electrical contact with the terminals of the battery (batteries). In their turn, the electrically conductive limbs are connected to a part to be energized of the electrical appliance.