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MAKING GEARS OR TOOTHED RACKS (by stamping B21D; by rolling B21H; by forging or pressing B21K; by casting B22; arrangements for copying or controlling B23Q; machines or devices for grinding or polishing, in general B24B)
Definition statement
This subclass/group covers:

Methods and machines specially designed to accurately produce the shapes of gears and other toothed members. Such shapes being essential for proper intermeshing of gearing (and toothed member) elements to ensure the required relative motions. The methods and machines use metal removing processes;

Tools which are specially adapted for use in machines for manufacturing toothed members;

Accessories and equipment for gear making machinery.

References relevant to classification in this subclass
This subclass/group does not cover:
Making gears or toothed racks by stamping
Making gears or toothed racks by rolling
Making gears or toothed racks by forging or pressing
Making gears or toothed racks by casting
Informative references
Attention is drawn to the following places, which may be of interest for search:
Details, components, or accessories for machine tools, in general
Machines or devices for grinding or polishing, per se
Gears, per se
Profiles of toothed members
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Gear teeth
In addition to the common meaning of gear teeth, it also covers the teeth or lobes of other accurately-intermeshing members having relative movement of a similar kind, such as rotors of rotary pumps and blowers
Profile
profile may include the outline of both faces or only one face of a tooth, or the opposing faces of adjacent teeth
Straight
straight means that a tooth as a whole (ignoring any curvature of the tooth-face alone, e.g. crowning) is straight in the direction of its length. It accordingly includes the teeth of helical gears and normal bevel gears
Broach-milling
broach-milling refers to milling with a rotary cutter having a number of teeth of progressively increasing depth or width
Making gear teeth by tools of which the profile matches the profile of the required surface (special adaptations for making curved teeth B23F 9/00 )
Definition statement
This subclass/group covers:

Methods and machines for making gear teeth using a tool which matches the required tooth profile. This group includes making spur and bevel gears. The methods and machines include grinding, planing, milling and broaching. Both rough machining and finishing are included.

Examples are:

Manufacturing by grinding (JP59161226):

Manufacturing by milling (GB383884):

Manufacturing by broaching (JP4025313)

References relevant to classification in this group
This subclass/group does not cover:
Gear cutting tools
Informative references
Attention is drawn to the following places, which may be of interest for search:
Gear generating methods and machines for straight teeth
Gear generating methods and machines for curved teeth
Special rules of classification within this group

Where a machine may be also be used for generating gear straight teeth it is classified in the subgroups of both B23F 1/00 and B23F 5/00.

by grinding
Informative references
Attention is drawn to the following places, which may be of interest for search:
Chamfering gear teeth by grinding
Gear generating by grinding
Grinding, in general
[N: the tool being a grinding worm]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Gear generating using a grinding worm
by planing or slotting
Informative references
Attention is drawn to the following places, which may be of interest for search:
Gear generating by planing or slotting
by milling
Informative references
Attention is drawn to the following places, which may be of interest for search:
Milling, in general
Gear generating by milling
Making gear teeth involving copying operations controlled by templates having a profile which matches that of the required tooth face or part thereof or a copy thereof to a different scale (copying systems or devices per se B23Q 35/00 )
Definition statement
This subclass/group covers:

Machines and methods for making gear teeth using templates which have a profile matching at least a part of the required tooth profile. This class includes roughing and finishing, including chamfering teeth.

Example: DE763595

Informative references
Attention is drawn to the following places, which may be of interest for search:
Copying systems or devices per se
Making straight gear teeth involving moving a tool relatively to a workpiece with a rolling-off or an enveloping motion with respect to the gear teeth to be made
Definition statement
This subclass/group covers:

Machines and methods of making straight gear teeth involving moving the tool relatively to work piece with a rolling-off motion, e.g. generating. The methods include:

  • grinding, with a grinding worm or grinding disc
  • planing, including skiving
  • milling, including hobbing

Example(s):

By grinding (US4400916)

by planing or slotting (EP1342524)

by hobbing (GB406730)

Informative references
Attention is drawn to the following places, which may be of interest for search:
Making curved gear teeth
the tool being a grinding worm
Informative references
Attention is drawn to the following places, which may be of interest for search:
Making straight gear teeth involving moving a hob relatively to a workpiece with a rolling-off motion (spur gears)
Making straight gear teeth involving moving a hob relatively to a workpiece with a rolling-off motion (bevel gears)
Special rules of classification within this group

Methods and machines which may use either a grinding worm or a hob are to be classified in both B23F 5/04 and B23F 5/22

[N: the tool and workpiece being in crossed axis arrangement, e.g. skiving, i.e. "Waelzschaelen"]
Definition statement
This subclass/group covers:

Example (DE102007015357)

Synonyms and Keywords

In patetn documents the following expressions/words "Skiving" and "hob peeling" are often used as synonyms.

the tool being a hob for making spur gears
Informative references
Attention is drawn to the following places, which may be of interest for search:
Gear manufacturing hobs, per se
the tool being a hob for making bevel gears
Informative references
Attention is drawn to the following places, which may be of interest for search:
Taper hobs for manufacturing bevel gears
Making herringbone gear teeth
Definition statement
This subclass/group covers:

Methods and machines for making herringbone teeth.

Example (US20040031152):

Synonyms and Keywords

In patent documents the following expressions/words " Herringbone gears" and " double helical gears" are often used as synonyms.

Making gears having teeth curved in their longitudinal direction
Definition statement
This subclass/group covers:

Methods and machines for making gears having teeth curved in their longitudinal direction, e.g. spiral bevel gears, hypoid gears.

Example (US20050064794)

(US20020154961)

[N: with a face-mill-type, i.e. cup-shaped, grinding wheel]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Face-mill-type grinding tools
Special rules of classification within this group

Methods and machines relating to both face-mill-type grinding and face milling using milling cutters are classified in both B23F 9/025 and B23F 9/10.

having a shape similar to a spur-wheel or part thereof
Informative references
Attention is drawn to the following places, which may be of interest for search:
Gear shaper cutters having a shape similar to a spur gear or part thereof
[N: with a hob]
References relevant to classification in this group
This subclass/group does not cover:
Face hobbing
Informative references
Attention is drawn to the following places, which may be of interest for search:
Hobs for gear cutting
[N: the hob being tapered]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Tapered hobs
with a face-mill
Informative references
Attention is drawn to the following places, which may be of interest for search:
Face mills for gear cutting
Special rules of classification within this group

Methods or machines relating to both face-mill-type grinding and face milling using a milling tool are classified in both B23F 9/10 and B23F 9/025.

[N: with continuous indexing, i.e. with continuous work rotation]
Definition statement
This subclass/group covers:

Methods and machines for manufacturing curved gear teeth by milling with a face mill with continuous indexing, i.e. face hobbing.

Making worm wheels, e.g. by hobbing
Definition statement
This subclass/group covers:

Methods and machines for manufacturing worm wheels, where worm wheels are the mating gears for worms. Both rough and finish machining are included.

Example of manufacturing by hobbing (GB362448, Figure 4):

Informative references
Attention is drawn to the following places, which may be of interest for search:
Making worms
Making worms by methods essentially requiring the use of machines of the gear-cutting type (making screw-thread B23G )
Definition statement
This subclass/group covers:

Machines and methods of the gear-cutting type used for making worms. Both rough and finish machining are included.

Example (US5647703)

Informative references
Attention is drawn to the following places, which may be of interest for search:
Making worm wheels
Making worms of globoidal shape
Definition statement
This subclass/group covers:

Methods and machines for making globoidal, e.g. hourglass shape worms.

Example (US3875635)

Methods or machines for making gear wheels of special kinds not covered by groups B23F 7/00 to B23F 13/00
Definition statement
This subclass/group covers:

Methods and machines for special types of gear wheels and toothed members, e.g. sprockets, elliptical wheels, pump rotors, toothed clutches and face (crown) gears.

Example (US4521141)

Making gear teeth on the front surface of wheels, e.g. for clutches or couplings with toothed faces
Definition statement
This subclass/group covers:

Methods and machines for making gear teeth on the front surface of wheels.

Example, clutches (GB594492)

Example: Face gears (EP0906171):

Making intermeshing rotors, e.g. of pumps
Definition statement
This subclass/group covers:

Example (US4034645):

Special methods or machines for making gear teeth, not covered by the preceding groups
Definition statement
This subclass/group covers:

Special methods and machines for making gear teeth, not covered by other groups. Examples are methods and machines for making gear pairs, machines for machining tooth roots and machines which combine different machining operations.

[N: for machining tooth fillet or tooth root]
Definition statement
This subclass/group covers:

Example (JP61117014):

[N: using different machines or machining operations]
Definition statement
This subclass/group covers:

Example (US20090060672)

[N: Features relating to transfer of work gears between different work stations]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Arrangements for handling work with machine tools, in general
Finishing gear teeth by other tools than those used for manufacturing gear teeth
Definition statement
This subclass/group covers:

Methods and machines for finishing gear teeth. The finishing process may include modifying the tooth form by crowning, by chamfering and by the provision of undercuts and stop notches. The group also includes deburring.

Example (EP1106290)

[N: using a face-mill-type tool, e.g. a milling or a grinding tool]
Definition statement
This subclass/group covers:

Example: (US5580298)

Lapping gear teeth
Definition statement
This subclass/group covers:

Example (US20080113592)

Informative references
Attention is drawn to the following places, which may be of interest for search:
Lapping in general
Honing gear teeth
Definition statement
This subclass/group covers:

Example (US4077164)

Informative references
Attention is drawn to the following places, which may be of interest for search:
Honing tools for gear teeth
[N: by making use of a tool in the shape of a worm]
Definition statement
This subclass/group covers:

Example (US3740904)

Informative references
Attention is drawn to the following places, which may be of interest for search:
Honing worms for gear teeth
[N: by making use of a tool in the shape of an internal gear]
Definition statement
This subclass/group covers:

Example (DE4317306)

Shaving the faces of gear teeth
Definition statement
This subclass/group covers:

Example (GB801289):

Informative references
Attention is drawn to the following places, which may be of interest for search:
Shaving cutters for gear teeth
[N: by making use of a tool in the shape of an internal gear]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Shaving cutters in the shape of an internal gear
Chamfering the end edges of gear teeth
Definition statement
This subclass/group covers:

Methods and machines for chamfering and deburring, including secondary deburring of the end edges of gear teeth.

Example (EP1022082)

[N: the tool being a fly cutter]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Fly cutters for use in gear manufacture
Tools specially adapted for use in machines for manufacturing gear teeth
Definition statement
This subclass/group covers:

Tools specially adapted for use in machines for manufacturing gear teeth such as:

  • Grinding tools
  • Honing tools
  • Planing or slotting tools
  • Milling tools
  • Broach and broach-milling tools
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Inserted cutting elements
is understood as meaning that the tool has a body and cutting elements which take the form of inserts are fixed into the body.
Inserted cutting elements in exchangeable arrangement
is understood as meaning that the inserted cutting elements can be removed and replaced by new inserts when required.
Grinding discs; Grinding worms (truing grinding tools B24B ; grinding tools in general B24D )
Definition statement
This subclass/group covers:

Example (US4533812):

[N: Face-mill-type, i.e. cup-shaped, grinding wheels]
Definition statement
This subclass/group covers:

Example (EP1184122)

Informative references
Attention is drawn to the following places, which may be of interest for search:
Making curved gear teeth with a cup-shaped grinding wheel
[N: Grinding worms]
Definition statement
This subclass/group covers:

Example (JP6297243):

Informative references
Attention is drawn to the following places, which may be of interest for search:
Making straight teeth where the profile matches the profile of the required surface using a grinding worm
Generating straight teeth using a grinding worm
Honing tools
Definition statement
This subclass/group covers:

Example (WO9924203)

Informative references
Attention is drawn to the following places, which may be of interest for search:
Honing gear teeth
[N: Honing worms]
Definition statement
This subclass/group covers:

Example (US3740904)

Informative references
Attention is drawn to the following places, which may be of interest for search:
Honing gear teeth with a honing worm
Planing or slotting tools
Informative references
Attention is drawn to the following places, which may be of interest for search:
Generating straight teeth by planing or slotting
Making curved teeth by planing or slotting
having a profile which matches a gear tooth profile
Informative references
Attention is drawn to the following places, which may be of interest for search:
Making straight teeth where the profile of the tool matches the profile of the required surface by planing or slotting
having the same profile as a tooth or teeth of a rack
Definition statement
This subclass/group covers:

Example (GB146769):

Informative references
Attention is drawn to the following places, which may be of interest for search:
Making straight gear teeth using a rolling-off or enveloping motion by planning or slotting where the tool has the same profile as a tooth or teeth of a rack
Gear-shaper cutters having a shape similar to a spur wheel or part thereof
Definition statement
This subclass/group covers:

Gear shaper cutters having a shape similar to a spur wheel or part thereof, e.g. pinion cutters

Example (GB220192)

Informative references
Attention is drawn to the following places, which may be of interest for search:
Making straight teeth involving a rolling-off motion by planing or slotting using a tool having the same profile as a spur wheel
Making curved teeth by planing or slotting using a tool having the same profile as a spur wheel
Milling tools
Informative references
Attention is drawn to the following places, which may be of interest for search:
Milling cutters, in general
[N: having a shape similar to that of a gear or part thereof, with cutting edges situated on the tooth contour lines]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Making straight teeth involving moving a tool relatively to a workpiece with a rolling-off motion by milling using a tool that has a shape similar to that of a gear or part thereof, with cutting edges situated on the tooth contour lines
Profile cutters of disc type
Definition statement
This subclass/group covers:

Example (GB590978):

Hobs
Definition statement
This subclass/group covers:

Example (JP59001120):

Informative references
Attention is drawn to the following places, which may be of interest for search:
Hobbing straight gear teeth
Hobbing curved gear teeth
[N: in exchangeable arrangement]
Definition statement
This subclass/group covers:

Example (DE1020090037903)

Taper hobs, e.g. for bevel gears
Definition statement
This subclass/group covers:

Example (GB955699):

Fly cutters
Definition statement
This subclass/group covers:

Example (EP0088807):

Face-mills for longitudinally-curved gear teeth
Definition statement
This subclass/group covers:

Example (GB 473050):

Informative references
Attention is drawn to the following places, which may be of interest for search:
Making curved gear teeth by face milling
Making curved gear teeth by face hobbing
[N: in exchangeable arrangement]
Definition statement
This subclass/group covers:

Examples:

Face milling cutter (US3571876)

Face milling cutter for face hobbing (US6609858):

Broach-milling tools
Definition statement
This subclass/group covers:

Example (GB364012, Figures 2 and 3):

Informative references
Attention is drawn to the following places, which may be of interest for search:
Broach-milling of gear teeth using a tool whose profile matches the profile of the required surface
Broach-milling straight teeth involving a rolling-off motion
Broaching tools
Definition statement
This subclass/group covers:

Example (US20040109731)

Informative references
Attention is drawn to the following places, which may be of interest for search:
Broaching gear teeth using tools where the profile matches the required surface profile
Broaching straight teeth using a rolling-off motion
Broaching curved gears
[N: mounted on an endless chain or belt]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Broaching straight teeth with tools mounted on endless belt or chain
Broaching curved teeth with tools mounted on an endless belt or chain
[N: Pot broaches]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Pot broaching using tools whose profile matches that of the required surface
Shaving cutters
Definition statement
This subclass/group covers:

Example (JP62114817):

Informative references
Attention is drawn to the following places, which may be of interest for search:
Shaving gear teeth
[N: having the shape of an internal gear]
Definition statement
This subclass/group covers:

Example (JP61030322):

Informative references
Attention is drawn to the following places, which may be of interest for search:
Shaving gear teeth using a tool in the shape of an internal gear
Accessories or equipment combined with or arranged in, or specially designed to form part of, gear-cutting machines (tool-guiding mechanisms, see the relevant groups for making gear teeth; accessories or equipment not restricted to gear-cutting machines B23Q )
Definition statement
This subclass/group covers:

Accessories and equipment specially designed to form part of gear cutting machines, e.g.

  • generating, indexing and synchronising mechanisms
  • loading, unloading and work holding equipment
  • Tool holders
  • Dressing arrangements for grinding wheels

Examples:

Tool / workpiece contact detecting device (US20030002943)

Loading / unloading (US6565418):

[N: Equipment for synchronising movement of cutting tool and workpiece, the cutting tool and workpiece not being mechanically coupled]
Definition statement
This subclass/group covers:

Example (US20050055836):

Informative references
Attention is drawn to the following places, which may be of interest for search:
Numerical control (NC) of machine tools in general
Loading [N: or unloading] arrangements
Definition statement
This subclass/group covers:

Example (GB1394518)

Informative references
Attention is drawn to the following places, which may be of interest for search:
Handling work in machine tools in general
Chucking arrangements
Definition statement
This subclass/group covers:

Example (GB1256167):

Informative references
Attention is drawn to the following places, which may be of interest for search:
Chucks, in general
Arrangements for compensating irregularities in drives or indexing mechanisms
Informative references
Attention is drawn to the following places, which may be of interest for search:
Automatic control and compensation for machine tools, in general
[N: Tool mountings]
Definition statement
This subclass/group covers:

Tool mountings, i.e. actual clamping device

Informative references
Attention is drawn to the following places, which may be of interest for search:
Workpiece mounting, e.g. chucking arrangements
Gear cutting tool holders
[N: Checking devices for controlling workpieces in machines for manufacturing gear teeth]
Definition statement
This subclass/group covers:

Example (US5174070):

Informative references
Attention is drawn to the following places, which may be of interest for search:
Measuring arrangements using mechanical means for measuring contours of gears
Measuring arrangements using electrical or magnetic means for measuring contours of gears
Testing of gearings
[N: Arrangements of abrasive wheel dressing devices on gear-cutting machines (dressing devices per se B24B 53/00 ) ]
Definition statement
This subclass/group covers:

Example (US6146253 (dressing tool, 56))

[N: using a gear-shaped dressing tool]
Definition statement
This subclass/group covers:

Example (JP20060035421)

[N: Hob holders] In this phase, definitions are only mandatory for main group level and above.
Definition statement
This subclass/group covers:

Example (DE1020090039752)

Informative references
Attention is drawn to the following places, which may be of interest for search:
Hobs for manufacturing gear teeth
[N: Face mill holders]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Face-milling tools for cutting curved teeth
[N: Rack cutter holders]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Planing or slotting tools having the same profile as a tooth or teeth of a rack
[N: Grinding disc holders; Disc-type milling-cutter holders]
Definition statement
This subclass/group covers:

Example (DE3415498):

Informative references
Attention is drawn to the following places, which may be of interest for search:
Securing milling cutters to the driving spindle, in general
Grinding discs for use in gear manufacturing machines
Profile cutters of disc type for use in gear manufacturing machines
[N: Face-mill-type grinding wheel holders]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Face mill type grinding wheels for use in gear cutting machines
Synonyms and Keywords

In the patent documents the following expressions/words " Face mill type grinding wheel" and "cup-shaped grinding wheel " are often used as synonyms.

[N: Grinding or honing worm holders]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Grinding worms for use in gear manufacturing machines
Honing worms for use in gear manufacturing machines
[N: Honing, shaving or lapping tool holders]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Honing tools for use in gear manufacturing machines
Shaving tools for use in gear manufacturing machines
[N: Pinion shaper cutter holders]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Pinion shaped cutters for use in gear manufacturing machines
This page is owned by Office of Patent Classification.
Last Modified: 10/11/2013