May 15, 2012
Reading time 7 min.
Close-Up: Carl F. Bucherer Patravi EvoTec PowerReserve
In 2010, Carl F. Bucherer added a power-reserve indicator to its Patravi EvoTec watch, launched the year before, thus creating the Patravi EvoTec PowerReserve. WatchTime gives the watch and its in-house movement a thorough once-over in the May-June issue 2012 issue. Click here to read the story and see stunning photos by Zuckerfabrik Fotodesign.
There’s no missing watch's power-reserve display: its bright red, yellow and green make it stand out like a traffic light against the watch’s black dial. The automatic caliber CFB A1002, based on the A1000, Carl F. Bucherer’s first in-house movement, ticks beneath the dial, powered by a rotor that runs in circles around the movement’s outer edge and is the best-known feature of the A1000 family of calibers.
The watch has a highly domed, sapphire crystal. The case, water-resistant to 50 meters, is made of steel. Despite its ample size (44 by 45 mm) and hefty weight (139 grams), the Patravi fits well on the wrist.
The smell of the natural rubber coating on the crown and bezel detracted a bit from the wearing pleasure of the watch, but the rubbery odor diminished as our review progressed. The good thing about the rubber on the crown is that it creates a soft surface that is easy to grasp. (Click on photos for larger images.)
Carl F. Bucherer PatraviEvoTec Power Reserve
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However, when the hands have been set to show the correct time, pressing the crown back into its closed position causes the minutes hand to jump. Overcoming the play in the minutes hand requires a bit of patience. Not only must the hand be manually adjusted back and forth; the crown, too, has to be closed very carefully and along an exact vertical axis.
The calfskin strap adds to the good fit; although its padding was a bit stiff at first, the strap soon became more flexible. The strap also keeps the clasp well away from the inside of the wrist, thus preventing scratching. The strap and clasp have a solid feel. They both work well, once you learn how to slide the end of the strap through the clasp correctly. The process isn’t intuitive, but it does assure a secure hold and a precisely adjusted length. Screwed sprung crosspieces make it easy to remove one strap and insert another. The only criticism we had about the craftsmanship of the strap was that we found a bit of excess glue on the leather of the lining.
The calfskin strap and steel clasp are a solid combination.
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The craftsmanship of the dial is nearly flawless: the only drawback was the somewhat fuzzy printing on the day display. High contrast and ample space between the strokes on the scales ensure that the time can be read instantly and accurately. The inner ends of the markings follow the contours of the pillow-shaped case, and the minutes and hour hands have sharp points that contribute to good legibility. The tips of these hands glow in the dark, as do the hour indices, which are so widely spaced that the time can be estimated more or less to the nearest minute, except when the minutes hand is passing through the dark arc next to the power-reserve display. The small seconds, day, date and power-reserve display all disappear at night.
We liked the dial's appliqués and brushed pattern, but found the printing on its big date display to be somewhat fuzzy.
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The time can be read to the nearest minute at night.
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The watch we reviewed always ran a bit fast. It gained between 1 and 4 seconds per day during our wearing test. After leaving the watch unworn for nearly 24 hours, we found that the daily gain had increased to 7 seconds. The gain returned to its familiar low range the following day.
Our timing machine test also showed that the watch ran a bit fast, but its maximum gain was just 4.6 seconds (in the crown left position) after being allowed to run for 24 hours without winding. We were less pleased with the balance’s amplitude; when the watch was fully wound and measured in the “dial down” position, the amplitude was 316 degrees, i.e., on the threshold of knocking.
Nevertheless, the Patravi’s rate values were all very good. Although the movement is not a chronometer, it ran accurately enough to earn COSC certification. The mean daily rate was +3.3 seconds, the mean deviation of rate was 1.8 seconds, the difference between vertical and horizontal positions was –0.9 seconds, and the greatest difference between the average daily rate and one of the other rates was 3.3 seconds. All of these values are within the tolerances specified by COSC.
For a look at caliber A1002, flip the Patravi over. The transparent caseback reveals shimmery metal, handsome alternating satiny, matte and sunburst-brushed surfaces, and brightly polished screws that provide attractive accents.
The movement has no ornamentation such as bluing and wavy patterns. This results in a clean look that’s furthered by the straight lines of the bridges. Except for a scratch and a tiny dent, the processing was immaculate. The base caliber is identified below the balance rim: caliber A1000 was developed to serve as the basis for an assortment of manufacture calibers by Carl F. Bucherer Technologies SA, which has been the brand’s in-house movement manufacturer since 2007. The various calibers differ according to their added modules, i.e., their complications.
The A1000 was designed to drive an hour hand, a minutes hand and a small seconds hand. The A1002 has been upgraded with a module to display the day of the week, the date and the power reserve.
The power reserve display's red pointer moves through an arc as the power winds down.
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Like the A1000, the A1002 has a peripheral rotor that circles around the center of the movement along the outer edge of the sapphire window in the Patravi’s caseback. This rotor offers a complete view of the movement, similar to that seen in hand-wound watches. To devise this peripheral rotor, the movement designers at Carl F. Bucherer had to think differently than if they had been creating a conventional central rotor. Conveying power and safeguarding the circular bearing against shocks were also concerns.
These two requirements literally intermesh. The inner side of the circular rotor has a serrated edge. These inwardly oriented teeth enable the oscillating weight to mesh in every position with a transmission wheel that conveys kinetic energy to the gear train to wind the mainspring. The transmission wheel is recognizable because it’s equipped with Incabloc shock absorption, which is borne in the wheel’s pivots. Its counterpart is hidden from view beneath the wheel. The shock absorbers enable the transmission wheel to follow the rotor in case a lateral blow causes the oscillating weight to shift toward the side.
The rotor itself is protected against impacts by Dynamic Shock Absorption (DSA), which was developed by Carl F. Bucherer Technologies. This shock-absorption system is based on three bearings that operate with ceramic balls. In each bearing is a pin, around which runs a notch shaped like a leaning V, which serves as the surface along which the rotor moves. The ball bearings can readily shift laterally and, most importantly, vertically toward the plate, thereby compensating for shocks whenever the oscillating weight is pressed toward its running surface.
Caliber A1002 has a peripheral rotor with a DSA shock-absorption system and CDAS protection for components used to finely adjust the balance.
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Another in-house invention is the patented safety system for finely regulating the balance. The Central Dual Adjusting System (CDAS) holds the regulator and the hairspring stud in position, even when the movement is subjected to strong force. This system is also used in caliber A1002.
The inventiveness of Carl F. Bucherer, the distinctive peripheral rotor and the smooth functioning of the A1002 in everyday use lead us to give this movement a very positive review. The movement’s only shortcomings, and admittedly very minor ones, were the two small blemishes in the processing of the movement.
The entire watch did very well on all fronts: high user friendliness and wearing comfort, excellent craftsmanship and quality in the case, an elaborately and cleanly crafted dial and good daytime legibility. Its only flaws were fuzzy printing on the day display, the absence of luminosity in one arc along the hour scale, remnants of glue on the strap, a rubbery smell from the crown, and too much play in the minutes hand. However, all of these details are far outweighed by positive features.
Carl F. Bucherer Patravi EvoTec Power Reserve front view
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Pros
+ Excellent craftsmanship and quality of the case
+ Good daytime legibility
+ Very comfortable to wear and convenient to operate
+ Manufacture caliber
+ Very good rate performance on the wrist and on the timing machine
+ Many special features in the design and construction
Cons
– Relatively high price
– Less-than-ideal nighttime legibility
– Excessive play in the minutes hand
SPECS:
Manufacturer: Carl F. Bucherer Montres S. A., Langensandstrasse 27, CH-6002 Lucerne, Switzerland
Reference number: 00.10627.13.33.01
Functions: Hours, minutes, small seconds, day, large date, power-reserve display
Movement: In-house movement CFB A1002, automatic, (base caliber CFB A1000); 21,600 vph; 33 jewels; diameter
= 32 mm; height = 6.3 mm; Incabloc shock absorber; flat Nivaflex hairspring, Glucydur balance; 55-hour power reserve
Case: Stainless-steel case with rubber bezel; curved sapphire crystal in front is nonreflective on both sides, sapphire caseback; water resistant to 50 meters
Strap and clasp: Calfskin strap with folding clasp
Dimensions: 44.14 mm by 45.14 mm; height = 14.34 mm; weight = 139 grams
Variations: Stainless-steel case and bezel; stainless-steel bracelet, $12,100; rose-gold case with brown dial and rubber bezel on brown calfskin strap, $35,200
Price: $11,200
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