KOCH'S
PARCEL & LETTER SCALE

parcel and letter scale, maker Koch, Germany

The enamel dial reads Koch's Paquet & Brief Waage, translated: Parcel & Letter Scale by Koch. The scale was probably made by the Patent-Waagenfabrik Gebrüder Koch, these are the brothers Carl and Ferdinand Koch who had a company of that name in Hannover, Germany from 1884-1897. This dial also says Patent. It appears that this scale is a combination of several patented constructions, see the figures below of patent DE62152 and DE63281, both patents were published in 1892. In Maß und Gewicht no.30 of June 1994 on pp695 and pp697-700 the Koch's Paquet & Brief-Waage is described by Dirk Schmitz. In it patent DE56587 from 1891 is mentioned as the patent belonging to this weighing scale. That does not seem correct to me. Equilibrium published a translation of the article in 1995, see EQM 1995 issue No. 3, pp1917 and pp1919-1923. The specimen described has a slightly different indication of the parcel weighing range on the dial, 12 KIo instead of 12 Ko. It also says

back of the old scale

Ohne Federkraft and Oest.Ung. Patent. translated: Without Spring Force and Austrian-Hungarian Patent. The designation Ohne Federkraft and the specification Oest.Ung. Patent. for being patented are not on my copy. At the bottom of this page is the dial of a Koch scale that weighs up to 15 kilos. The letter scale part is missing from the scale in the article.
My copy bought on an auction site also lacked the letter scale part, the pointer turned out to be bent, fortunately a loose part came with the scale. After viewing and moving the partially assembled scale, and looking at several patents held by Koch, I added a letter scale section, thus completing the scale again. It became clear where the loose part had to be placed, and the dimensions for the stabilizing rods were provisionally determined using two flat popsicle sticks. A bracket folded from welding wire was attached to the now no longer loose part to hang weights on. In this way the weight of the letter tray to be made with a supporting bracket was determined. The size of the missing letter plate, the thickness of the brass plate and the sizes of the supporting bracket were devised by me. Later the popsicle sticks were replaced by steel strips. The pointers are correctly set to zero after the refurbishment and both the parcel scale and the letter scale are working again. The pointer is driven by a segment of a large gear on a small gear on the pointer shaft. A strange detail is that this shaft also has a wheel with a chain with a small weight attached to it, which probably pulls the play in one direction. Unfortunately, the chain can come out of the wheel during transport of the scale and then block the pointer movement. Disassembling the cover cap on the back of the dial is then necessary to place the chain with weight back in the running wheel, this is an annoying job. The height of the scale is 21.5 centimeters, the wooden plate measures 26 x 19 cm. The surface of the brass letter plate is 10 x 12 cm.
A kitchen scale from Koch has been shown before, see here, this scale also has a large cast iron frame.
Below are some more images of this old parcel & letter scale made by the Koch brothers. Finally, an image from the Verkehrszeitung und industrielle Rundschau from 1893, the Koch scale was briefly discussed on page 8.

side view

animation: the letter plate loaded with 150 grams the hand does indeed move to the left, counterclockwise [move the pointer over the photo]

side view

there are two weighing ranges: on the inner circle with the short hand part up to 500 grams per 5 grams on the outer circle with the long hand part up to 12 kilos per 50 grams

animation: place the 200 grams weight on the letter plate [move the pointer over the photo]

Koch's Paquet & Brief Waage 12 Ko Patent.

schematically drawn: the letter scale part with parallelogram with on the left the large counterweight it includes a threaded end with a spherical head with this the double pointer can be set to zero

the slightly different dial from the article in Maß und Gewicht: Koch's Paquet & Brief Waage 12 KIo Ohne Federkraft Oest.Ung. Patent.

This bowl hangs in the same way as the letter scale part in the weighing mechanism, also the gear segment and the gear on the pointer shaft are identical seen from the back of the scale (figure from patent DE63281)

the parcel weighing part pulls on the arm with the counterweight via the steel belt and the curve disc (figure from patent DE62152)

the dial and the clockwise rotating double pointer in patent DE63281 the inner circle up to 900 or 1000? Gramm and the short pointer belong to the bowl the outer circle up to 12 kilos with the long pointer belong to the large weighing dish on the photographed parcel & letter scale the pointer turns counterclockwise

it is very dusty, despite the cover on the back of the dial	gear segment on gear and small weight on chain	the still somewhat dirty enamel dial
the wooden shelf and the cover on the back of the dial have been removed to improve the view of the parts	various parts are numbered with 3 or with N3	image from the back, screwed plates cover the knife edge bearings
the support frame of the shelf is also marked N3	the counterweight marked 3. and the thread with ball head for fine adjustment	the steel belt and the curve disk are visible on the left and top left
dust and dirt have been removed here	the small oval flat weight hangs from the chain	the wheel on which the chain is wound
the popsicle sticks became makeshift stabilizer bars	view of the bottom of the scale	the parcel scale shelf looks used
the steel tension belt and the curve disk	the steel tension belt and the curve disk	the steel tension belt and the curve disk
the popsicle sticks built in as makeshift stabilizer bars	temporary bracket to use weights to determine how heavy the letter plate to be made with support may be	the built-in popsicle sticks and on the right the temporary bracket from which some weights hang
the black painted metal stabilizer strips for the letter scale	mounted here and the ends slightly bent to prevent loosening	the new strips are not annoyingly noticeable

the brass letter plate and the support folded from welding wire	the letter plate is fixed to the support with 4 brass nails	support fixed on the plate, the 4 nails are shortened and flattened
back of the renovated and almost complete scale	the letter plate is attached to the weighing mechanism	the letter plate is attached to the weighing mechanism

animation: two kilos on the parcel scale [move the pointer over the photo]

animation: 20 grams on the letter scale [move the pointer over the photo]

two kilos on the parcel scale	six kilos on the parcel scale	ten kilos on the parcel scale
back of the rebuilt and re-completed scale	the cover has been reattached to the back of the dial	details from the side

an incomplete Koch scale on the cover of Maß und Gewicht No. 30, June 1994

detail of the front of an incomplete Koch scale

an incomplete Koch scale on the cover of Equilibrium 1995 issue No.3

the dial of a Koch scale weighing up to 15 kilos Koch's Paquet & Brief Waage 15 Ko Ohne Federkraft Oest.Ung. Patent.

the Koch scale for parcels and letters depicted in Verkehrszeitung und industrielle Rundschau from the year 1893 on page 8 N.B. this letter plate is not flat