Improvements relating to wiper arm assemblies

Abstract: An armpiece (1) is placed into an open trough configuration of a retainer (2) (as shown at (4) and side portions (5) are then swaged over to wrap around the armpiece (as shown at (6). The armpiece incorporates a hole or depression and a punch is used to drive the material of the swaged arm portions (5) inwardly into the hole in the armpiece (1). The distorted material (9) so formed locks the armpiece (1) and the retainer (2) securely together so that the armpiece cannot move inwardly or outwardly of the retainer (2).

Description: A wiper arm assembly forms a linkage between the drive motor and the wiper blade of a windscreen wiper and conventionally comprises two parts, namely a retainer and an armpiece. In the final construction of such a wiper arm assembly it is required that the end of the armpiece should be securely held within the retainer. The tip of the armpiece often provides a mounting for a compression spring which holds the wiper arm down onto the windscreen. Consequently there is a force (provided by the spring) tending to pull the armpiece further into the retainer. Secure fixing of the armpiece is therefore very important. A wiper arm assembly of FR-A-2099853 comprises an arm piece and a retainer, the retainer having side portions which are swaged over one end of the arm piece, a depression is formed in part of said one end of the arm piece below the swaged over side portions of the retainer and a punched distortion of the material of the side portions into the recess in the arm piece holds the arm piece firmly within the retainer, the material of the side portions has been driven into a depression recess or hole to cause a partial shear of the material of the retainer. In accordance with the present invention, in a wiper arm assembly of this type, regions of the facing terminal edges of the side portions mutually overlap with one another in the longitudinal direction of the wiper arm assembly, and parts of the side portions which are to be distorted by a punch have been precut to facilitate punching, these precut parts being shaped to overlap one another in the longitudinal direction. The punched distortion of the retainer material into the depression, recess or hole in the armpiece holds the two parts together in a fixed condition even against a force provided by the retaining spring. It may be preferred that the shape of the punched distortion of the material of the retainer corresponds to the shape of said depression, recess or hole. It is possible, however, to have a small depression, recess or hole in the armpiece whilst a wide bladed but pointed punch is used to drive the material of the retainer down towards the depression, recess or hole so that only the parts of the retainer material near to the point of the punch are driven into the depression, recess or hole. The invention may be performed in various ways and a preferred embodiment thereof will now be described, by way of example, with reference to the accompanying drawings, in which:- Figures 1A and 1B illustrate the formation stages of a wiper arm assembly in accordance with the invention. The retainer 2 shown in the drawings has side portions 5 (which are swaged over the armpiece 1) of a special form. These have mutually overlapping parts 15 projecting into recesses 16. Each of the parts 15 has a central cut 17 so that when, as shown in Figure 1B, a punch 18 is driven onto the segments 19 of the parts 15 these segments only will driven downwardly into a recess in the armpiece 1. The remaining segments 20 provide a degree of interlocking of the side portions 5.

Claims: A wiper arm assembly comprising an armpiece (1) and a retainer (2), the retainer having side portions which are swaged over one end of the armpiece, a depression, recess or hole (16) formed in part of said one end of the armpiece underneath the terminal edges of the swaged over side portions (5) of the retainer and a punched distortion of the material of the terminal edges of the side portions into the depression, recess or hole in the armpiece to hold the armpiece firmly within the retainer, wherein the material of the side portions has been driven into said depression, recess or hole to cause a partial shear of the material of the retainer, characterised in that regions (15) of the facing terminal edges of the side portions mutually overlap with one another in the longitudinal direction of the wiper arm assembly and parts (19) of the side portions which are to be distorted by a punch have been precut to facilitate punching, these precut parts being shaped to overlap one another in the longitudinal direction. A wiper arm assembly according to Claim 1, wherein the shape of the punched distortion of the material of the retainer corresponds to the shape of said depression, recess or hole.

Inventors: CLEVELAND ALLEN JOHN, REES DAVID ALWYN, ROBERTSON ALISTAIR DUNCAN, CLEVELAND, ALLEN JOHN, REES, DAVID ALWYN, ROBERTSON, ALISTAIR DUNCAN
Applicants: TRICO PRODUCTS CORP, TRICO PRODUCTS CORPORATION
Application year: 1997
Main classification: B60S1
IPC codes: B60S1