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The Encyclopedia of Horology

Pocket watch · Clamshell pocket watch

Pforzheimer, Dreyfus & Keller Fitch Patent Sterling Silver Pocket Watch Case #6175 with American Watch Co. Movement

Partially verified

This pocket watch features a sterling silver clamshell case manufactured based on Ezra C. Fitch's design patented on June 9, 1874, and sold by Pforzheimer, Dreyfus & Keller. Bearing case serial number 6175, the construction encapsulates the center section to produce a single continuous seam along the exterior perimeter when shut. The source reports that the case houses an 18-size Appleton, Tracy & Co. movement produced by the American Watch Company in Waltham, numbered 993144. According to the article, this piece represents the only known surviving sterling silver example of this particular Fitch patented case design.

Profile view of open P.D.&K. sterling silver Fitch patent clamshell pocket watch case showing bezel, center body, and case back
Profile view of open P.D.&K. sterling silver Fitch patent clamshell pocket watch case showing bezel, center body, and case back — Pocket Watch Database Blog / Anonymous Contributor. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
blog.pocketwatchdatabase.com
Category
Pocket watch · Clamshell pocket watch
Maker / attribution
Pforzheimer, Dreyfus & Keller
Reference
Patented June 9, 1874
Catalogue / lot identifier
Source URL identifies the listing
Source-reported date
Circa 1874
Country
United States
Source-reported serial
6175

Source-reported attribution and specifications are not independent authentication. A listing does not establish present ownership, current display, availability or permission to reproduce.

Object description

Case Design and Construction

The object features a clamshell pocket watch case identified under case number 6175, constructed in sterling silver according to the patented design of Ezra C. Fitch. As described in the source report, the structure encapsulates the center section to produce a single continuous seam along the exterior perimeter when closed.

In the profile photograph, the case is shown open on a shared hinge mechanism, revealing the front bezel and rear cover swinging away from the central body. Opposite the hinge, a polished silver pendant neck and bow are affixed.

Evidence for this section
  • “encapsulate the center of the case like a clamshell, leaving a single seam around the perimeter of the case.”
  • “Side profile view displaying the opened front bezel and opened rear case cover attached by a shared hinge.”

Retailer Markings and Attribution

The case bears markings associated with the retailer Pforzheimer, Dreyfus & Keller. These interior stamps include a P, D, and K surrounding an illustrative depiction of a set of scales, along with the text 'Sterling Silver' embossed inside an arched banner.

Credit to Fitch is recorded by the stamped patent date 'Patented June 9, 1874'. The source author notes that this specific example represents the only known surviving sterling silver specimen of the PDK 'beveled invisible centre' case.

Evidence for this section
  • “marked with a P, D, and K surrounding an illustrative depiction of a set of scales.”
  • ““Sterling Silver” is embossed inside an arched banner, and “Patented June 9, 1874” is included to credit Fitch for the design.”
  • “This image represents the only known surviving example of the PDK sterling silver “beveled invisible centre” case.”

Reported Movement and Visual Limitations

According to the source documentation, the case houses an 18-size Appleton, Tracy & Co. movement numbered 993144, produced by the American Watch Company in Waltham. This caliber configuration mirrors pairings documented in previously recorded 18K gold variants of the patent.

Physical inspection is restricted by the single available profile image, which displays only a stepped movement ring, the bezel rim, and a fraction of the dial and hand arbor. Direct verification of the dial face, hand configuration, and internal movement plates cannot be completed from the provided view.

Evidence for this section
  • “The sterling silver case houses an 18-Size Appleton, Tracy & Co. movement manufactured by the American Watch Company (Waltham) [# 993144 ], consistent with the movement pairings found with the 18K cases.”
  • “Stepped central movement ring and bezel rim revealing a fraction of the dial and hand arbor.”

Open research questions

  • What are the specific dial characteristics, including numerals, signature, and sub-dial configuration, obscured in the profile photograph?
  • Does movement 993144 show evidence of being originally cased in this silver clamshell housing, or was it fitted subsequently?

Source evidence

Recorded claims and source quotations for Pforzheimer, Dreyfus & Keller Fitch Patent Sterling Silver Pocket Watch Case #6175 with American Watch Co. Movement
FieldSource-reported valueSource quotation
Case Retailer / SellerPforzheimer, Dreyfus & Keller“P.D.&K. Sterling Silver Case #6175”
Patent DateJune 9, 1874““Patented June 9, 1874” is included to credit Fitch for the design.”
Case Number6175“P.D.&K. Sterling Silver Case #6175 – Fitch “Beveled Invisible Centre””
Movement MakerAmerican Watch Company (Waltham)“manufactured by the American Watch Company (Waltham) [# 993144 ]”
Movement Grade18-Size Appleton, Tracy & Co.“The sterling silver case houses an 18-Size Appleton, Tracy & Co. movement”
Case MaterialSterling Silver““Sterling Silver” is embossed inside an arched banner”
Movement Serial Number993144“manufactured by the American Watch Company (Waltham) [# 993144 ]”
Maker Trademark MotifScales illustration flanked by P, D, and K“marked with a P, D, and K surrounding an illustrative depiction of a set of scales”

Visible details

  • Side profile view displaying the opened front bezel and opened rear case cover attached by a shared hinge.
  • Stepped central movement ring and bezel rim revealing a fraction of the dial and hand arbor.
  • Polished silver pendant neck and bow affixed opposite the hinge mechanism.

Research qualifications

  • The dial surface, hands, and inner movement plate are not fully visible in the profile photograph.
  • Movement serial number and inner markings are reported by the source and confirmed in accompanying text, not visible in this angle.

Photograph identity and source facts were screened before import; rights clearance remains pending.

Consulted source

Ezra C. Fitch Rare Patented “Beveled Invisible Centre” Watch Case Design Sold By Pforzheimer, Dreyfus & Keller: Part 2 - The Silver Case - Pocket Watch Database Blog

Reviewed 2026-10-21 · Record 6b2d0ab70f

Terms in this record

Glossary explanations for terms named in this object’s record.