Accession No
6169
Brief Description
easy slide Bristow coil (medical shocking coil), by Stanley Cox Ltd., English, early to mid-20th Century
Origin
England; London; 2 Gerrard Street, W. 1.
Maker
Stanley Cox Ltd.
Class
medical; electrical
Earliest Date
1910
Latest Date
1940
Inscription Date
Material
wood (teak); plastic (pvc; foam); metal (stainless steel; brass); rubber; leather
Dimensions
width 200mm; height 200mm; depth 220mm
Special Collection
Provenance
Donated on or before 23/01/2003. The donor collected the instruments over many years, predominantly from private sales, some were obtained direct from the manufacturers who were going to throw them out.
Inscription
EASY SLIDE BRISTOW COIL
STANLEY COX LTD
II GERRARD ST
LONDON W.I.
No. 1131
PATIENT
Description Notes
Easy slide Bristow coil (medical shocking coil) by Stanley Cox, early to mid twentieth century
Object consists of teak box, which has a large lid (with leather handle on top), hinged (brass) at the rear, plus a hinged door (with key lock - key included on string) at the front which exposes the inside of the lower half of the box. On top of this lower half, fully exposed once the lid is opened, is a black plastic surface, on top of which is the Bristow Coil (inside a black plastic casing) at one end of which are the interrupters contacts, consisting of a flexible stainless steel arm (with weight at one end), plus a point contact on a metal stand. This can be moved by means of a screw, and would have been connected in series to a battery power supply.
Also on the plastic surface are two large black plastic control knobs, one that can be rotated to set at values between 1 and 4, the other can be set to “OFF”, “M” and “C”. Next to these knobs is a pair of metal screw fittings to hold wires, marked “PATIENT”.
Below this plastic surface in the bottom half of the box is three loose items:
- two rubber tourniquets
- two metal contact pads, with wooden handles and single black sheathed wires attached.
clamped inside the lid is a large, orange, plastic insulated handle.
The right side of the box contains a hole, possibly for inserting a battery power source.
References
Events
Description
The Bristow coil is an induction coil device designed to produce a very high voltage output from a low voltage D.C. Supply (for example a battery).
An induction coil consists of two coils of insulated copper wire wound around a common iron core. One coil, called the primary, is made using tens or hundreds of turns of coarse wire. The other coil, called the secondary, typically consists of many thousands of turns of fine wire.
The interrupter's contacts at one end of the Bristow coil are wired in series between a battery and the coil. The contacts are closed in their resting state. When power is applied, the coil is activated which produces a magnetic field at the metal core of the coil. The magnetic contact arm on the interrupter is pulled toward the core, opening the interrupter contacts and breaking the circuit. The falling magnetic field relaxes its hold, the contacts close, and the entire cycle repeats.
The rising and falling magnetic field of the primary coil induces a high voltage across the secondary. This high voltage output was then used, in the case of this instrument, for medical shock treatment, most likely physiotherapy treatment of muscle conditions. By using electric shocks to stimulate the movemnt of damaged muscle, strength can be re-built into muscle that a patient would have difficulty moving voluntarily.
05/09/2007
Created by: Joshua Nall on 05/09/2007
FM:46635
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