The Wrenn brothers were granted patents on their Formula 152 range. The first being 844.436 which was quoted in the February 1961 Price List with ‘others pending’. The November 1962 Price List also listed 894.837 with still ‘others pending’. By the time of one of the last Catalogues (possibly the last one) 894.838 had also been added. Overseas Patents were stated as pending on the first Price List and not mentioned again on subsequent Price Lists although later Price Lists from November 1962 did state ‘other Patents pending’.

The actual Patents are available to view on the Espacenet website so I have downloaded the information and drawings for each of them below. Since the Patents are only granted for 20 years, they are now obviously out of date but also in the public domain.


Abstract of GB 844436 (A)

Electrically propelled toy vehicles. Jan. 19, 1959, No. 1863/59. Class 132(3). [Also in Group XXXV]

844.436An electrically propelled toy vehicle, e.g. a scale model racing car, comprises a body 26 mounted on a chassis 11 of magnetic material, e.g. soft iron, which carries an electromagnet coil 12 and a hinged armature 24. This operates a spring loaded pawl 17 which in turn engages a ratchet wheel 18. The ratchet wheel may be of hard steel or plastic, e.g. nylon, and is secured to a shaft 19 joumalled in the frame and carrying road wheels 29. A further shaft 27 carrying road wheels 28 is journalled either in the chassis as shown or in the frame. Make and break contacts 22 operated by a projection 24 on the armature are disposed on top of the coil, and current is taken from a prepared track having two conducting strips by two collector shoes 30. In an alternative arrangement (not shown), for A.C. operation only, the make and break contacts are dispensed with and the armature consists of a tuned reed resiliently mounted.


Abstract of GB 844437 (A)

Miniature-vehicle tracks.

844.436Sept. 17, 1959 [July 28, 1959], No. 25865/59. Classes 132(2) and 132(3) A miniature-vehicle diverting device is such that it will divert an electrically powered vehicle by engaging a guide member or members on each vehicle with a member in a vehicle guiding slot to lift the guide member or members from the slot and to divert the vehicle from one lane of a track so that it will run under its own momentum to an adjacent lane. Each lane has a guide slot, e.g. 25, Fig. 1, engageable by one or more downwardly projecting guide members from a vehicle and also has electrically conductive strips 28 to 31 inserted in it engageable by current collectors. Each vehicle has a pair of current collectors, the collectors of different vehicles on the same lane engaging different pairs of conductors so that, by controlling the current supply to the strips, the speed of the different vehicles can be independently controlled. Figs. 3 and 4 show an insert frictionally fitted in a guide slot, the insert comprising an upwardly sloping face 47 and a laterally slanting face 49. As a vehicle travels along the lane its guide member is raised out of the lane slot by the face 47 and is deflected sideways by the face 49. Thus the vehicle is deflected from its lane to an adjacent lane where its guide member drops into a guide slot and its collectors make contact with the conductors. Fig. 6 shows an alternative embodiment where a similarly shaped deflector is pivoted at 51 and is operated through a cranked spindle 55 by a lever, Bowden cable or solenoid. Vehicles may be raced by controlling the diverting devices and current to the strips, the vehicles overtaking each other by changing from one track to another and back again. According to the Provisional Specification, instead of a guide slot, a raised guide rail having conductor strips incorporated in it or a pair of guide grooves for miniature-car wheels may be used. The Provisional Specification also describes overhead wires for miniature trolley buses or trams and points similar to those used in model railway tracks. Specification 844,436 is referred to.


Abstract of GB 8944838 (A)

Miniature vehicle tracks.

894.837Jan. 20, 1960, No 2068/60. Class 132(3) A miniature rail track assembly comprises a flat base member 1 having linear recesses 7 in its upper surface, inverted channel section rails 3 to 6 inserted in the recesses, and holes 10 drilled in the base member upwards meeting the recesses, the side flanges of the rails having been splayed into the holes by a swaging tool 11 to hold the rails in position. The rails may be electrical conductors, miniature road vehicles such as disclosed in Specification 894,837 each having collectors to pick up current from a selected pair of rails. As shown, the track has channels 2 which are engaged by projections from the vehicles. Track sections are joined by projecting pieces 13 each of which may be a short length of inverted channel of smaller gauge than a rail so that it can be pushed within a rail channel. These pieces 13 may be splayed in position simultaneously with the splaying of the rails. Rails are splayed in position while the base 1 is inverted on an anvil surface. To provide rails flush with the track surface a flat anvil is used, to provide sunk rails the base when inverted is meshed with a ribbed anvil, and to fit rails which project from the track, so that they may receive flanged wheels, a grooved anvil is used to receive the projecting rail tops. The track assembly may be made from a moulded or extruded synthetic plastics substance, may be formed in complete circles or ovals, and may comprise more than one track.