ERICSSON BULLETIN
No. 19 PAGE No. 26


Time Recorders
JULY 1949

The statement “time is money” is supported by the fact that most of the recordings obtained from attendance or work-timing devices are used in connection with money payments or charges. It follows, therefore, that accuracy and reliability are essential in such devices, especially at the present time when owing to reduced working hours attempts are being made to increase the productivity per man-hour, which means, in effect, that minutes are tending to become of greater value in £.s.d.

It is now almost universal practice in industrial concerns of any size, to use automatic recorders for attendance or work timing, and whilst the machines described here may be used for either purpose they are primarily designed as attendance recorders.

In addition to accuracy and reliability, attendance recorders must be speedy in operation and also capable of withstanding rough usage. Apart from the convenience aspect, the choice of site is largely a matter of common sense, the most usual location being on the wall of a corridor near the cloakrooms.

Certain types of time recorders are arranged for manual “setting“ but in the interests of accuracy it is desirable to eliminate the human element as far as possible, therefore, in modern design, setting is done automatically.

The Company is engaged in the production of two types of recorders; one is fully automatic, i.e., the location and stamping is performed automatically when the card on which the recordings are made is inserted, and the other is automatic for the location of the recordings but the stamping is done manually after the card is inserted. For the purposes of illustration, views of the fully automatic recorder are shown.

In order to maintain consistent and accurate timekeeping over a complete installation, recorders are made to operate on minute impulses supplied by a master clock of suitable type, or by a synchronous motor working on frequency controlled a.c. mains.

Recordings are made on a ruled card, approximately 7” x 4” x .011” / .009” thick, on which each day of the week is represented by a separate vertical column. Consecutive recordings during the same day up to a maximum of eight, are printed one below the other, independent of the time interval.

The machine registers in hours and minutes and the standard marking is for 12 hours with p.m. hours underlined, but 24 hour marking and decimal divisions of the hour in place of the minute marking can be arranged.

Printing can be made in red or blue during different periods of the day, providing successive changes are not less than 12 minutes apart. For one day of the week the programme of colour changes can be made to deviate from the normal arrangements, if desired.

Fig. 1
A Fully-automatic Time Recorder
Fig. 2
Time Recorder with Cover Removed

It will be seen from Fig. 1 that the unit is compact and has a neat appearance, and that the interior is well protected from dust or damage by a closely fitting enamelled steel cover which has a Yale type lock.

External connections are made by means of a plug and socket in order to facilitate maintenance and inspection.

The internal apparatus is supported from thick mild steel side plates (Figs. 2 and 3) held together by spacing bolts, and all bearing holes are bushed with manganese brass.

Fig. 3
Rear View of Recorder Assembly

The mechanism comprises two sections, one being the time controlled units for indicating the time of day and for setting the characters and colour in preparation for stamping, and the other, the units for locating the card in the correct position and making the registration.

TIME CONTROLLED MECHANISM
The time controlled mechanism is driven from the main spindle (Fig. 4) on which is a 30-tooth ratchet wheel operated step-by-step at one-minute intervals by means of a pawl controlled by the armature of an electro-magnet. Pulses of 1 second duration sent out from the master clock, or its equivalent, are used to energize the twin coils of the magnet and the movement of the paw! takes place when the armature is released. A spring, brought forward to engage a gear-wheel on the spindle, prevents any movement of the latter whilst the armature is in the operated position.

Fig. 4
Main Drive Spindle with Operating Pawl and Armature
Fig. 5
Programme Unit (left) and Hour Trip Spindle and Marking Wheels (top centre)

Fitted behind a window in the front cover is a 4-inch clock face (Fig. 2), the hands for which are carried on an axle geared from the main spindle with a ratio of 1:2 for the minute hand and 1:12 for the hour hand, the latter being fixed to a sleeve over the axle.

MARKING WHEELS
This assembly, shown in the top centre of Fig. 5, comprises two die-cast wheels, embossed on the periphery for marking the hour and minute on the record card, two gearwheels and a trip disc.

The minute marking wheel, a 60-tooth gearwheel and the trip disc, are pinned securely to a spindle, the gearwheel engaging with another on the main driving spindle. The hour marking wheel and a 48-tooth gearwheel are keyed together and are free to revolve on the marking wheel spindle.

A spindle with pinion is fitted to engage the trip disc and the 48-tooth gearwheel so that for each revolution of the minute wheel the hour wheel is stepped forward 1/24 of a revolution.

PROGRAMME UNIT
To position the card holder for the appropriate day, control the colour of the printing and provide a means of operating an audible signal if required, a programme unit is employed. This unit may be seen on the left in Fig. 5 and includes four programme wheels, two being used for the respective a.m. and p.m. 12-hour periods over six consecutive days, and the remaining two for the a.m. and p.m. periods for the seventh day. A fifth wheel which carries a cam, is moved every time either of the p.m. wheels is operated, the cam working the day change mechanism which is released at midnight.
Each programme wheel is a die-casting having on its periphery 144 slots, spaced to represent intervals of five minutes. Hardened spring steel pins can be inserted in/the slots to give any required time interval, the pins being bent when necessary to register minutes within the five minute spaces. The pins pass under the claws of a lever fitted across the face of the wheels and cause the slow rise and quick fall of a pendulum link on the side of the programme unit. This movement is utilized for colour setting.

COLOUR SETTING (Fig. 6)
A two-colour inked ribbon is used for printing, and colour changing is brought about by moving up or down the frame carrying the ribbon, to bring the appropriate colour into position for the marking wheels. This movement of the frame takes place during the stamping operation but the colour setting mechanism functions at the specific pre-arranged time. The components used in the colour setting operation are the pendulum link mentioned above, and a setting plate which is fitted on a pin projecting from the recorder frame. A flag which is visible through an aperture in the clock dial (opposite 9) is attached to the setting plate and indicates the colour the machine is set to print.

The setting plate is shaped like a “W “, the centre point of which is free to move to a position on each side of the centre line of the link on the programme unit. As the link is lifted clear of the point of the W, by the action of the pins in the programme wheel, it swings and hangs vertically and when released, is made to fall on the side of the point opposite to that from which it was raised, thus turning the setting plate. With every rise and fall of the link the plate is turned in this manner.

Fig. 6
Colour Setting and Colour Change Mechanism

CARD HOLDER AND CARD POSITIONING MECHANISM
The card holder consists of a die cast mouthpiece riveted to a pressed steel frame which is screwed to a brass bracket carried on a worm spindle. (Fig. 5). The latter engages a thread in the carrier bracket to step the card holder from right to left corresponding to the day columns on the card.

The stepping movement is effected by a lever which is lifted by the programme unit during the p.m. hours and when the lever is released at midnight it causes a pawl to engage a ratchet wheel which drives the worm spindle by means of a gearwheel and pinion.

Teeth are removed from the gearwheel in positions corresponding with every seventh step, to allow the card holder to slip back to its starting position at the end of a week.

The gearwheel may be seen on the left in Figs. 5 and 6.

Recordings made on a card during the same day are positioned vertically one below the other as follows:- A hole is punched in a card every time a recording is made (Fig. 7). A pointer, which is situated above the punch, is spring-tensioned against the face of tile card and engages in the hole punched during the previous recording, to effect the correct location of the card for stamping.

Fig. 7
Card Locating and Punching Unit

REGISTRATION
The printed record is made by means of an arm carrying a rubber pad which strikes the card and presses it against the inked ribbon under which the characters on the marking wheel are situated.
On fully automatic machines the striking arm is operated by an electro magnet which is energized by contacts fitted on the punch and vertical locating mechanism. These contacts are made when the card is correctly positioned and are automatically broken when the armature carrying the striking arm is fully operated. Interlocking levers make it impossible to operate the contacts again until the card is withdrawn and a new location made.
On the manually operated machines a pawl on the handle spindle engages a trip lever fixed to the striking arm. When the handle is depressed the striking arm is moved back against strong springs and is released suddenly at a set distance. in this way the weight and speed of printing is consistent under all conditions of the manual action.
The two-colour inked ribbon is carried round a die-cast frame and is moved after each registration, being wound off one bobbin on to another. The action is automatically reversed just before the unwinding bobbin becomes empty and when the ink is exhausted the ribbon is easily replaced. A lever with roller, which is operated at the same time as the striking arm, moves the ribbon frame up or down according to the relative position of the colour setting plate.
With the development of the fully automatic machine, numerous tests were made to obtain the maximum efficiency from the electrical operation of the stamping mechanism, in order to keep the time required for this function to a minimum.

A high-speed film, 28003000 frames per second, was made of the complete armature operation, which takes place in approximately 1/10 second, and the slow projection of this film proved to be of considerable assistance in the design of the movement.

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Last revised: June 22, 2003