Practical Perpetual Calendars: Innovative, Convenient and Green

By James R. Saltvold

Perpetual calendars are a fascinating way to look at time, and can be defined in a variety of ways. In a comprehensive how-to manual, James Saltvold shares valuable insight on how to use his unique concepts to make practical perpetual calendars for everyday home and office use. These calendars, which save resources and look like a conventional calendar, can be set to display any month for any year within their range. They are set by simply moving a slider, and typically have a range of 50 to 100 years.

Saltvold uses skills he acquired during an engineering career to present design ideas and concepts for calendars that are easy to produce and use. After providing a brief description of the four types or categories that his calendars fi t into, Saltvold leads readers on an informative journey, enhanced by figures and tables. He explains how to bring calendar prototypes into mass production, describes products that can be made from the four types of perpetual calendars, details which products might be attractive to various markets and manufacturers, and shares a brief history of his own work in developing concepts and researching patents. Additional sections include material on where to search for more information on perpetual calendars, as well as references with comments.

Practical Perpetual Calendars includes designs for desk calendars, wall calendars, pocket calendars, photo holders, and other applications. The calendars shown on the front cover are described on the following pages: wall calendar (p. 129), clock (p. 77), pocket calendar (p. 68), full-year calendar (p. 157), 7-column desk calendar (p. 145), and 13-column desk calendar (p. 120).

• Language: English
• Publisher: iUniverse
• Release date: Oct 27, 2017
• ISBN: 9781532021367

James R. Saltvold

James R. Saltvold is a retired instrumentation engineer who spent most of his career in the Canadian nuclear power industry. He currently resides with his wife, Roberta, in Red Deer, Alberta, Canada. This is his first book. Details of some of the designs in Practical Perpetual Calendars can be found on Saltvolds website www.jamessaltvold.com. The website also has some notes on personal saving and investing for Canadians.

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Copyright © 2017 James R. Saltvold.

All rights reserved. No part of this book may be used or reproduced by any means, graphic, electronic, or mechanical, including photocopying, recording, taping or by any information storage retrieval system without the written permission of the author except in the case of brief quotations embodied in critical articles and reviews.

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Because of the dynamic nature of the Internet, any web addresses or links contained in this book may have changed since publication and may no longer be valid. The views expressed in this work are solely those of the author and do not necessarily reflect the views of the publisher, and the publisher hereby disclaims any responsibility for them.

Cover background imagery © Thinkstock.

ISBN: 978-1-5320-2135-0 (sc)

ISBN: 978-1-5320-2136-7 (e)

Library of Congress Control Number: 2017908051

iUniverse rev. date: 10/26/2017

To Roberta

CONTENTS

List of Figures

Preface

Acknowledgments

Introduction

Chapter 1 Four Unique Perpetual Calendars

Chapter 2 From Concept to Mass Production

Chapter 3 Tables for Single-Sheet Perpetual Calendars

Chapter 4 Tables for Multisheet and Full-Year Perpetual Calendars

Chapter 5 Single-Sheet Perpetual Calendars—Applications and Products

Chapter 6 Multisheet Perpetual Calendars with a Year Table on Each Sheet—Applications and Products

Chapter 7 Multisheet Perpetual Calendars with a Single Year Table—Applications and Products

Chapter 8 Full-Year Perpetual Calendars—Applications and Products

Chapter 9 Applications and Products Summary

Appendix History, Patents and Manufactured Perpetual Calendars

Further Reading

Annotated References

LIST OF FIGURES

Figures 1-1a to 1-1d: Single-sheet perpetual calendars

Figure 1-2a to 1-2d: Multisheet perpetual calendars with a year table on each sheet

Figure 1-3a to 1-3d: Multisheet perpetual calendars with a single year table

Figure 1-4a and 1-4b: Full-year perpetual calendar

Figure 5-1a: Body of a single-window tent desk calendar made from cardstock

Figures 5-1b to 5-1d: Slider and other details for a single-window tent desk calendar

Figure 5-1e: Single-window desk calendar made from wood

Figure 5-2a: Double-window desk calendar made from cardstock

Figures 5-2b and 5-2c: Alternate construction of double-window desk calendar and wood model

Figures 5-3a and 5-3b: Pocket calendars—moving-window type and moving-slider type

Figure 5-3c: Pocket/tent calendar

Figure 5-3d: Fold-down moving-slider pocket calendar

Figure 5-3e: Pocket calendar with a single slider and year tables beside the window

Figure 5-4: Bookmark calendar

Figure 5-5: Calendar for a lamp or a pencil holder

Figure 5-6a: Cardstock 4 × 6 inch photo holder with dual sliders—design A

Figure 5-6b: Cardstock 4 × 6 inch photo holder with dual sliders—design B

Figure 5-7a: Key holder with a dual-slider calendar

Figure 5-7b: Key holder with single-slider calendar

Figure 5-8: Clock with a dual-slider calendar

Figure 5-9: Clock with a single-slider double-window calendar

Figure 5-10a: Picture frame with calendar beside photo

Figure 5-10b: Picture frame with calendar beside photo (detail)

Figure 5-11: Picture frame with calendar below photo

Figure 5-12: Dual-slider calendar with 5 × 7 inch picture frame above it

Figure 5-13a: Modifications to commercial sliding-window 13-column calendar

Figure 5-13b: Redesigned commercial sliding-window 13-column calendar

Figures 5-14a and 5-14b: Monthly wall planner with 13 columns

Figures 5-15a and 5-15b: Monthly wall planner with 7 strips

Figure 5-16a: Line-style monthly wall planner

Figure 5-16b: Vertical-slider 3-ring binder planner

Figure 5-17a: Ornate hybrid wall calendar, sheet 1 of 3

Figure 5-17b: Ornate hybrid wall calendar, sheet 2 of 3

Figure 5-17c: Ornate hybrid wall calendar, sheet 3 of 3

Figure 5-18: Stand for commercial perpetual desk calendar

Figure 6-1a: Typical month sheets for a 14-sheet flip-down-window desk calendar

Figure 6-1b: Flip-down-window desk calendar made from cardstock

Figure 6-2: Two holder designs for the lift-out-pad desk calendar

Figure 6-3: Four different formats for wall calendar sheets

Figure 6-4: Flip-down-window wall calendar

Figure 6-5: Clip-on-window wall calendar

Figure 6-6: Lift-out-pad wall calendar

Figures 6-7a and 6-7b: Two patterns for a window-on-each-sheet wall calendar

Figure 6-8: Extension of single-sheet calendar to multisheet

Figures 7-1a to 7-1d: Multisheet calendar with a single year table

Figure 7-2: J-style wall/desk calendar

Figure 7-3: Reverse J-style desk calendar

Figure 7-4: Wooden frame desk calendar

Figure 7-5: Multisheet single-year table calendar below a 5 × 7 inch picture frame

Figure 7-6a: Seven-column multisheet calendar with a single year table—body and slider

Figure 7-6b: Seven-column multisheet calendar with a single year table—assembled

Figure 7-6c: Seven-column multisheet calendar with a single year table—day-of-month sheets

Figure 8-1a: Face of the full-year calendar with a double-sided slider

Figure 8-1b: Common year side of the double-sided slider for the full-year calendar

Figure 8-1c: Leap year side of the double-sided slider for the full-year calendar

Figure 8-2a: Slider for the single-sided slider full-year calendar

Figure 8-2b: Face of the full-year calendar with a single-sided slider

Figure 8-3: Vertical full-year perpetual calendar

Figure 8-4a: Single day-of-month table full-year calendar with a horizontal slider

Figure 8-4b: Single day-of-month table full-year calendar with a vertical slider

Figure A-1: An early attempt at lookup tables

Figure A-2: An early version of the single-sheet perpetual calendar with dual-slider configuration

Figure A-3: State of the dual-slider design in October 2012

Figure A-4: Moving-window tent calendar

Figure A-5: A variation of a multisheet perpetual calendar with a single year table

Figure A-6: Slider-type perpetual calendar, United States Patent 1,949,328, February 27, 1934

Figures A-7a to A-7c: Magnetic-type, slider-type and triple-cylinder-type perpetual calendars

Figures A-8a to A-8e: Common rotary one-month calendar compared to my single-window desk calendar

Figures A-9a to A-9d: Four types of commercial perpetual calendars

Figure A-10: Conceptual drawing of the face of a full-year calendar with 24 windows for the months

PREFACE

Practical Perpetual Calendars—Innovative, Convenient and Green describes development work that I have done to make stand-alone perpetual calendars viable replacements for all conventional calendars that are not written on. When doing this work, I applied the skills that I acquired during a long career as a design engineer to create and refine concepts that have the potential to make perpetual calendars a common home and office item.

Although various types of perpetual calendars have been around for a long time, none have replaced conventional calendars for everyday use. The ones available either require reference to a conventional calendar to set them or are difficult to read. And whereas some patents describe ideas that are close to what is needed to make a practical perpetual calendar, there has been, to the best of my knowledge, nothing manufactured or patented that is quite like my calendars.

The purpose of Practical Perpetual Calendars is to make print shops, manufacturers, small craft shops, and hobbyists aware of my novel and unique practical concepts for making stand-alone perpetual calendars. Calendars made from cardstock that incorporate these concepts have a useful life of 10 years or more, compared to just one year for conventional calendars. Calendars made from more durable materials could have a useful life of a century! My designs, which look almost the same as conventional calendars, save resources and eliminate the inconvenience of annual replacement.

Practical Perpetual Calendars includes designs for desk calendars, wall calendars, pocket calendars, photo holders and other applications. It also describes how the tables for the calendars are developed. I hope that readers will see the value of these calendars and take steps to put my concepts into both mass-produced and one-of-a-kind products.

ACKNOWLEDGMENTS

Thank you to my wife, Roberta, for your support and encouragement over the many years I was developing perpetual calendar concepts. Your comments on prototypes were invaluable in refining concepts to make the calendars practical. Thank you also, Roberta, for reviewing and editing Practical Perpetual Calendars.

Thanks to my publisher, iUniverse, for encouraging me during the writing process, for taking a manuscript and making it into a book and for guiding me through the publishing process.

Thanks in advance to the readers who accept the risks associated with manufacturing and marketing a new product in both large and small quantities. Your work is essential to convert my concepts into useful products.

INTRODUCTION

About This Book

Practical Perpetual Calendars shows how to make practical perpetual calendars for a wide variety of applications using unique concepts that I have developed.

What Is a Perpetual Calendar?

The term perpetual calendar does not seem to have a universal meaning. Three definitions are as follows:

• A chart or mechanical device that indicates the day of the week corresponding to any given date over a period of many years (American Heritage Dictionary of the English Language)¹

• A calendar in which the day, the month, and the date are adjusted independently to show any combination of the three (English Oxford Living Dictionaries)²

• A table for finding the day of the week for any one of a wide range of dates (Merriam-Webster Dictionary)³

Perpetual calendars that meet the definitions provided by the American Heritage Dictionary or the Merriam-Webster Dictionary can be considered stand-alone in that reference to a conventional calendar is not required to set them. Calendars that meet the Oxford Dictionaries definition are not stand-alone, as reference to another calendar is required to set them or to find the day of the week for a particular date. When a Bing or Google search is done to locate images of perpetual calendars, most of the images found meet one of the three definitions. The ones meeting the American Heritage definition are mechanical devices that have a part that is rotated (or moved in some other way) to line up the year and the month to obtain a display for a particular month, or where two or more parts are rotated (or moved in some other way) to indicate the day of the week for a particular date. An example of this type of device is the date display on watches. Many rotary devices display a month in an arc of a circle, which is not as pleasing to read as the rectangular grid of a conventional calendar. I have found some stand-alone perpetual calendars in patents that have sliding mechanisms and a rectangular grid display; however, these have the complication of requiring a table lookup, or they have some other characteristic that makes them, along with rotary calendars, unsuitable replacements for conventional calendars in most applications.

The calendars in many of the images found online meet the Oxford Dictionaries definition. These include

• blocks that are arranged to indicate month, day of the month and day of the week;

• markers that are moved along a numbered line; and

• tiles that are arranged to display the current month.

Some of these devices, such as a tile calendar, look like a conventional calendar after they are set up, but they are not stand-alone. And there are charts and tables that meet the Merriam-Webster definition.

In Practical Perpetual Calendars, the term stand-alone perpetual calendar means a calendar that, without reference to anything other than itself, can be easily set to display the day of the week for every day of the month when the year and the month are known. The year must be within the design range of the calendar, which typically is a period of 50 to 100 years.

Overview of Contents

Chapter 1 briefly describes the four types or categories that all of my calendars fit into. Chapter 2 discusses in general terms how to bring the prototypes in Chapter 1 into mass production. Chapters 3 and 4 explain how to develop the tables that are used. Chapters 5 to 8 describe products that can be made from the four types of perpetual calendars. Chapter 9 describes which products might be attractive to various markets and manufacturers. The Appendix gives a brief history of the work I did to develop the concepts, discusses some perpetual calendar patents and describes some typical manufactured perpetual calendars. The Further Reading section indicates where to search for more information on calendars, and the Annotated References section provides references with comments.

I hope that some readers will read Practical Perpetual Calendars from cover to cover and find value in my detailed descriptions. I suggest that everyone read the descriptions of the four basic types of perpetual calendars described in Chapter 1. After that, look at what is interesting to you. A scan of the List of Figures may reveal something. Alternatively, you can thumb through the figures at the end of the chapters, or read the descriptions in the chapters to find figures that spark your interest. The figures are more conceptual than detailed. However, enough detail is given so that useful products can be made from them with a small amount of effort.

In keeping with this book’s title, Practical Perpetual Calendars, I present design ideas and concepts for calendars that are easy to build and use. The ideas cover desk, wall, pocket and full-year calendars. There are also suggestions for how to add a perpetual calendar to picture frames, key holders, pencil holders, lamps, clocks and planners.

Use of the Concepts and Designs to Manufacture Products for Sale

I have developed the concepts and tables in Practical Perpetual Calendars without referring to anyone else’s work, and to the best of my knowledge, my arrangements and combinations of tables are not used in any commercial perpetual calendars that are presently available. While researching for the section on the patents that appear in the Appendix, I found that some of my concepts had been previously discovered, but I did not find any inventor who had put together perpetual calendars quite like mine. I believe that my book and the perpetual calendars it describes are truly unique in the following ways:

• I use concepts and tables to make calendars that are very similar in appearance to conventional calendars, but mine have the feature of being stand-alone perpetual calendars.

• I describe four different types of perpetual calendars.

• I provide a complete range of calendar sizes for various uses, and many suggestions for how my designs can be incorporated into other products so as to add a perpetual calendar to those items.

Although Practical Perpetual Calendars is protected by copyright, my understanding is that a copyright does not cover concepts, so anyone who uses ideas they discover within these pages has no obligation to me. From my review of a number of patents for perpetual calendars, I have concluded that some of the ideas in this book would have been patentable if I had chosen to disclose them by way of patents rather than by way of a book. Therefore, readers who use the new ideas presented in Practical Perpetual Calendars to manufacture calendars are effectively gaining access to patents without being required to pay royalties. Since this could be a benefit of far greater value than the cost of the book, I encourage manufacturers to send me a very modest gratuity of CAN$0.02 per calendar for the first 100,000 produced between now and December 31, 2027, in lieu of a royalty. The following table provides more details of the suggested gratuity.

The suggested gratuity of CAN$0.02 per calendar is based on calendars that sell for $1 or more each. When the price is less, the gratuity can be proportionally less, but the minimum payment should be $10. The gratuity can be paid to my PayPal account. Go to www.paypal.com and click on Send. In the box Their e-mail or phone number, enter [e-mail]. Next, enter the amount you would like to send, click Continue and click on Goods or services.

CHAPTER 1

FOUR UNIQUE PERPETUAL CALENDARS

Four Basic Types of Perpetual Calendars

All of my calendars are based on variations of the four arbitrarily defined basic types described in this chapter. They are as follows:

• Single-Sheet Perpetual Calendars

These calendars display one month at a time and use the same sheet for all of the months.

• Multisheet Perpetual Calendars with a Year Table on Each Sheet

These calendars also display one month at a time, but they use more than one sheet for the months. Each sheet has a year table on it.

• Multisheet Perpetual Calendars with a Single Year Table

These calendars also display one month at a time, but they use more than one sheet for the months. There is a single year table that is used by all of the sheets.

• Full-Year Perpetual Calendars

These are calendars that display all of the months of the year on one sheet.

In all of the above definitions, the term sheet can be thought of as a piece of paper or other material that has printing on one side. When a piece of paper has printing on both sides, it is two calendar sheets.

This chapter introduces the four basic types by comparing them to conventional calendars. All of the calendars in this chapter are made from cardstock. Some construction details for these calendars, along with variations and calendars made from other materials, are described in later chapters. Except for the full-year calendar, all of the calendars in this chapter are desk models. This is the largest potential market, as millions of desk calendars are discarded at the end of each year without any markings on them.

Single-Sheet Perpetual Calendars

The single-sheet perpetual calendar can be made in a single-slider or a dual-slider configuration. Figure 1-1a shows a simple low-cost single-sheet perpetual tent calendar with a single slider, and Figure 1-1b shows a basic tent calendar that it can replace. A quantity of 150 has been produced in colour at a cost of about $1.25 each. The calendar face is 4 inches high by 6.5 inches wide, and covers the entire 21st century. The back of the tent can display a picture, a table