Portable CCB for renters 1977
Original and New portable CCB
VOL 69 PART 4 JANUARY 1977
Portable Coin Collecting Box for Renters' Use
A new design of portable coin-collecting box telephone for use in renters' premises is described.
INTRODUCTION
Before 1966, coin-collecting-box (CCB) telephones used by the British Post Office (BPO) for both public call offices and renters' installations were immobile, generally being fixed to a wall. Public call offices are usually available for anyone to use throughout the day and night, and money deposited in them is collected by the BPO. Renters' CCBs are fitted in customers' premises, so that access to them is usually restricted and they can be of lighter construction than public call offices. The customer is billed for rental and call charges but retains any money deposited in the cash box. In 1966, a need was seen for a portable CCB for use in such locations as restaurants, hairdressing salons, garage forecourts, shops and public houses. CCB facilities were therefore combined with portability at short notice in the CCB No. 735, which was essentially a standard public-call-office pay-onanswer CCB cut down and painted red. It lacked a carrying handle and stowage for the connecting cord, although these were improvised in the later 1/735 version shown in Fig. 1; the capacity of the cash box was very limited. In 1972, it was decided to embark on a new design that would be more purpose-built and would not have the deficiencies of the earlier model. The task was to improve the ergonomic features and appearance, make good the deficiencies and, at the same time, use as many parts as possible of the existing pay-on-answer CCB mechanism to minimize
the cost and the number of spare parts needed for maintenance
purposes.
The development was carried out in co-operation with
industry, using the services of industrial design consultants.
The resulting product, the CCB No. 725 (shown in Fig. 2),
is the subject of this article.
PHYSICAL ASPECTS AND MOBILITY
The case is in 2 main parts: front and rear. For the prototype model (shown in Fig. 3), both parts were aluminium castings, and there was an integral carrying handle. A fixed cordstowage reel was mounted on the rear part of the case. On the final version, however, the construction was simplified and costs reduced by making the rear part of the case in sheet steel and dispensing with the integral handle and fixed cordstowage reel. This has resulted in a unit that could, if desired, be wallmounted. For use as a portable unit, it is attached to a tubular-steel frame (Coin-Box Holder No. I), which provides the carrying handle and cord-stowage space, as illustrated in Fig. 2. It will be possible to stock separately the CCB and its frame to cater for the wall-mounted and portable options. For the portable mode, an 8 m connecting cord is needed, and the CCB is screwed to the frame using the same holes as for securing the CCB to a wall. The frame and CCB together weigh 14 kg.
A trolley is available to which the CCB can be bolted through holes in its base (see Fig. 4). This enables the CCB to be wheeled about; for instance, to be taken alongside a customer's table in a restaurant, or a patient's bed in a hospital. The trolley also provides stowage for directories and the connecting cord. The painted parts of the case are yellow. This colour was chosen for its distinctiveness. It is also the international colour for telecommunications and the BPO Telecommunications Business house colour. The left-hand side of the front is clad in a stainless-steel plate that carries the operating instructions.
TELEPHONE UNIT
The telephone unit is a separate sub-assembly. A moulded plastics chassis carries the bell-set and a printed-circuit board similar to that used in the standard type-746 telephone. Provision is made for 2 press-buttons for extension-plan working. The chassis also carries the lock that secures the front part of the cover. The lock is arranged so that it is not subjected to any strain if an attempt is made forcibly to remove the front of the case. Any such strain is taken by an extension tongue on the lock which is in double shear between steel parts firmly attached to the front and rear parts of the case. The telephone unit is hinged about its right-hand edge to swing clear of the rear part of the case once the front part has been unlocked and removed, as shown in Fig. 5. The design allows scope for the telephone unit to be mounted separately in its own box as a wall-unit, or recessed into a suitable space in a wall.
CASH COMPARTMENT
The cash compartment is secured by a separate lock, and can be opened without unlocking the mechanism compartment, and vice versa. It has a capacity of 1800 cm3 compared with 390 cm3 for the CCB No. 735.
MECHANISM
The mechanism is basically a standard pay-on-answer mechanism (Mechanism No. 24), the lower part of which has been rearranged to reduce the height by about 115 mm. Any functional parts thus displaced have been relocated or redesigned. Wherever possible, existing parts have been used to minimize stocks of spare parts and to aid maintenance, but the ductways for both accepted and rejected coins are completely new. Accepted coins pass directly from the runway assembly and mask unit to the cash compartment via separate short guides. Rejected coins fall directly into a hopper from which they can be retrieved by pushing back a counter-weighted flap. Currently, the hopper and flap are of stainless steel, but the use of moulded plastics is being explored. The detecting relay (relay SU) for the line reversal that unlocks the coin slots has been repositioned vertically at the rear of the mechanism, just behind the coin-selection link, and has a new curved-wire linkage with the coin-acceptor interlock. The mask contact has been made a microswitch. A sheet-steel guard is provided to protect relay SU and the mask unit from damage should the mechanism be removed from the case and laid on its back. The separate plugs and sockets used to interconnect the pulsing and coin-accepting parts of a standard mechanism with the telephone circuit have been replaced by a single flexible cord; this is permanently connected to the mechanism and terminated in a 12-way plug, which is inserted into a socket on the telephone unit. When the mechanism has to be removed, a dummy plug with strapped terminals is inserted in the socket on the telephone unit to complete the telephone circuit, thus enabling emergency calls to be made if necessary. When not in use, the dummy is parked in a clip on the telephone unit. A detailed description of the pay-on-answer system, and the mechanism and its functions, has been given in an earlier article. (BASTOW; F. J., COLLINGWOOD, J. D., NEWELL, E., and PRICE, C. K. The Pay-on-Answer Coin-Box System. POEEJ, Vol. 51, p. 343, Jan. 1959. )