From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Design and modification of a rivetless bonnet hinge.
| Identifier | WestWitteringFiles\V\March1931-September1931\ Scan407 | |
| Date | 7th September 1931 | |
| HS.{Lord Ernest Hives - Chair} FROM DA{Bernard Day - Chassis Design}/EV.{Ivan Evernden - coachwork} C. to SG.{Arthur F. Sidgreaves - MD} BY E.{Mr Elliott - Chief Engineer} ORIGINAL RECEIVED 9 SEP 1931 RIVETLESS BONNETS. DA{Bernard Day - Chassis Design}/EV{Ivan Evernden - coachwork}2/M7.9.31. J 385. We thank you for the sample of side bonnet hinge of the Armstrong type made to our N. sch. 3304. Having now seen the model we are convinced that we ought to go on experimenting with this design as well as with the riveted one which you have in hand. In the case of the model you sent us we succeeded in pulling to pieces the side plate from its hinge, but there seemed to be no tendency for the top plate hinge piece to bend. We suggest that it would be worth while making up a bonnet on the lines of this design, with the following modifications: (1) The hinge material as well as the sheath material to be of .048 thick steel. The .064 steel looks unnecessarily thick, and as previously stated there seems no tendency for it to bend. (2) The amount of overlap or grip on our drawing is shewn as about .450". This we think could easily be reduced to .375" or even .312". It will be realised that it is not the length of turn over that is of use so much as the tightness of the grip at the top of the bend. (3) To stop the panel slipping out of the hinge material we see that there are several ways of overcoming this. We believe Hooper's are drilling and tapping the hinge material as indicated in the sketch below. Another suggestion is that used, we believe, by Armstrong's, and that is, at intervals of 2" or 3" to punch steel locally into the aluminium. This might be further facilitated if the aluminium had holes in it at intervals. However this should not be necessary. One's general impression is that the whole scheme is so neat and clean that one feels it is worth while persevering with the design and manufacture, as there appears to be hope that it could be made cheaply and satisfactorily. The cost of riveting must be very high on our present job. DA{Bernard Day - Chassis Design}/EV.{Ivan Evernden - coachwork} | ||