Torx
TORX (from English torque " Torque ") is the registered word mark for a screw -Mitnahmeprofil whose standard designation Hexalobular or outer hexagon round is. It is similar to the profile in a shaft-hub connection using a splined shaft . Only here the contour of the teeth is completely rounded: The rounding of the tooth tips merges directly into the tooth root rounding.
With Torx, compared to the classic hexagonal profile ( hexagon socket and external hexagon), the screw and tool are less stressed with radial forces and consequently less damaged. The torque is transmitted more directly via the radial parts of the tooth flanks instead of via the almost tangential surfaces of the hexagon.
The notch effect is very low with Torx.
There are internal Torx and external Torx screws. The designation T stands for Torx inner profile and was first launched on the market. Then the outer profile Form E ( external ) was developed. The size designations of the T-tools were set arbitrarily; on the other hand, at E the width across flats is derived from the corner dimension of the flanks.
Inner Torx screws are also known as I-star or inner star ( English star ). Based on the widespread external and internal hexagon screws , the Torx key attack is referred to as hexagonal in German standards . The hexalobular socket is standardized in EN ISO 10664. Various screw shapes are standardized in ISO 14579 - ISO 14587. The standards are also published as a DIN standard (DIN EN ISO). The designation internal serrated screw should be avoided because of the risk of confusion with the multi-tooth profile XZN .
General
The Torx profile is able to transmit high torques. Unlike Phillips -Schraubenköpfen due to the vertically extending drive faces no increased pressure force when tightening is required, and there are much less reverse-acting forces ( cam-out, see also axial force ). As a result, cordless screwdrivers with high torques can be used for quick fastening without damaging the inner profile. Another advantage of the Torx profile is that torsional forces do not act selectively at the corners (as is the case with the Allen system, for example ), but rather in the middle and flat on the flanks of the individual prongs. This makes the system significantly less subject to wear. The Torx system is particularly suitable for assembly robots in automatic production. Self-tapping or self-tapping screws are often used here, which cut or shape (metal) or stamp (plastic) the thread when screwing into a hole. The pneumatically or electrically driven screwdrivers should have an adjustable torque so that over-tightening and thus damage to the thread can be prevented. A special case are so-called plank screws with cutting tips, threads and smooth shafts, the small head of which is pulled into the surface of the plank wood when screwing on. Further applications are in surgery ( bone fracture treatment ) and in dentures ( implants ).
Also nail screws are offered with Torx head. So that the screws can be processed automatically or semi-automatically, they can be stored in a nail belt.
In the automotive sector, screws with a Torx drive are mostly processed automatically today, but not stored in a magazine, but by separating loosely delivered screws in automatic screwdrivers.
With the modification Torx-TR ( Tamper Resistant , tamper-proof) there is a pin in the center of the profile that prevents this screw from being turned with a normal Torx or slotted screwdriver. This profile is used on devices when unwanted access is to be made more difficult.
Brand and patent
"TORX" is a trademark of Acument Intellectual Properties in Michigan , which was registered in the 1970s as a word mark and in the 1990s as a word / figurative mark by Textron in Germany and whose protection continues to this day. The provisional end date of protection is December 31, 2022. In addition, the “TORX” trademark is registered and protected in around 20 other countries.
The patents on Torx, however, have now expired. A subsidiary of Acument, Camcar in Rockford (Illinois) , gave the dimensions of Torx to customers such as Ford and Chrysler from 1968 onwards , from which the ISO 10664 standard developed in 1988, entitled Hexalobular internal driving feature for bolts and screws . As a European standard in the German version, ISO 10664 bears the title hexalobular socket for screws .
Key sizes
The key sizes are designated with "T", "TX" or "Tx" (depending on the manufacturer), followed by a number. The sizes available range from T1 to T100. The table shows the diameter and maximum tightening torques in Nm . It should be noted that the maximum torque varies greatly depending on the screw material and the friction values in the thread.
| size | ∅ in inches a |
∅ in mm a |
Maximum tightening torque in Nm |
Screws according to EN ISO 14579, 14580, 14583 and 14584 |
Cheese head screws with large hexalobular socket DIN 34802 |
Set screws with hexagon socket DIN 34827 |
(SPAX) - Screws with thread dia. in mm |
|---|---|---|---|---|---|---|---|
| T1 | 0.035 | 0.89 | 0.02-0.03 | ||||
| T2 | 0.039 | 0.99 | 0.07-0.09 | ||||
| T3 | 0.047 | 1.19 | 0.14-0.18 | ||||
| T4 | 0.053 | 1.35 | 0.22-0.28 | ||||
| T5 | 0.058 | 1.47 | 0.43-0.51 | ||||
| T6 | 0.069 | 1.75 | 0.75-0.9 | M2 | M3 | ||
| T7 | 0.078 | 1.99 | 1.4-1.7 | ||||
| T8 | 0.094 | 2.39 | 2.2-2.6 | M2.5 | M4 | ||
| T9 | 0.098 | 2.50 | 2.8-3.4 | ||||
| T10 | 0.111 | 2.82 | 3.7-4.5 | M3 | M5 | 3 | |
| T15 | 0.132 | 3.35 | 6.4 - 7.7 | M3.5 | M6 | ||
| T20 | 0.155 | 3.94 | 10.5-12.7 | M4 | 3.5 - 5 | ||
| T25 | 0.178 | 4.52 | 15.9-19 | M5 | M8 | ||
| T27 | 0.200 | 5.08 | 22.5-26.9 | ||||
| T30 | 0.221 | 5.61 | 31.1-37.4 | M6 | M5 | M10 | 6th |
| T35 | |||||||
| T40 | 0.266 | 6.76 | 54.1-65.1 | M6 | M12 | 8th | |
| T45 | 0.312 | 7.95 | 86-103.2 | M8 | |||
| T50 | 0.352 | 8.94 | 132-158 | M10 | M8 | M16 | 10 |
| T55 | 0.446 | 11.32 | 218-256 | M12 | M10 | M20 | |
| T60 | 0.529 | 13.45 | 379-445 | M14 | M12 | M24 | |
| T70 | 0.619 | 15.70 | 630-700 | M16 | M14 | ||
| T80 | 0.689 | 17.50 | 943-1048 | M18 | M16 | ||
| T90 | 0.795 | 20.20 | 1334-1483 | M20 | |||
| T100 | 0.882 | 22.40 | 1843-2048 |
- Comparison of Torx inner profiles
Torx
Torx Plus
Torx-TR
Torx Plus Security
Screw types
Various screw types are standardized in DIN EN ISO standards as an alternative to the common types with hexagon socket or Phillips drive with hexalobular drive. They have similar, partly identical, dimensions to their counterparts with hexagon socket or Phillips drive.
| ISO 14579: | Hexalobular socket head cap screws |
| ISO 14580: | Hexalobular socket head cap screws, low head |
| ISO 14581: | Countersunk screws with hexalobular socket |
| ISO 14582: | Countersunk hexagon socket head screws, high head |
| ISO 14583: | Pan head screws with hexalobular socket |
| ISO 14584: | Raised countersunk head screws with hexalobular socket |
| ISO 14585: | Pan head tapping screws with hexalobular socket |
| ISO 14586: | Countersunk tapping screws with hexalobular socket |
| ISO 14587: | Raised countersunk tapping screws with hexalobular socket |
Alternatives, further developments
Torx Plus
The Torx Plus system is a further development of the Torx drive system (patented in Germany until the beginning of 2012). Compared to standard Torx, the cams have a different ("flatter") shape, which are described by contiguous ellipses, which results in a real drive angle of 0 ° in some areas. This means that even higher torques can be transmitted. It is possible to drive Torx Plus screws with normal Torx keys in an emergency (high wear), but not the other way around.
Torx Paralobe
Another further development of the Torx system is Torx Paralobe. The six percent lengthening of the flanks compared to Torx Plus resulted in a 20% higher torque.
Torx-TR
As a safety variant of the Torx screws Torx-TR ( T amper- R esistant, commonly referred to as a hole-Torx) a spigot which makes a special tool required. This Torx Tamper Resistant security screw has six tips - in contrast, the Torx Plus Security has five tips. The associated screwdrivers for Torx TR screws are often referred to as Torx BO or TH ( Torx with Hole ) for short .
Torx Plus Security
A further development of the safety screws with tenons and only 5 tips.
T-Star Plus
Under the name T-Star Plus , the company ABC markets Torx screws under the SPAX brand, which have a small, approx. 1.5 mm deep recess under the star. The corresponding bits have a correspondingly elongated shaft that fits into this recess. Small manufacturing tolerances of the shaft and recess lead to a secure fit of the screw on the tool, so that the screw does not usually have to be held by the second hand when it is screwed in. T-Star-Plus screws can be easily tightened and loosened with normal Torx bits, but normal Torx screws cannot be tightened with T-Star-Plus bits. The shank at the end of the latter prevents the bit from being fully immersed in the screw, which can lead to increased wear or breakage on the tool.
Assy-Würth
Under the name Assy , the Würth company primarily offers chipboard and wood construction screws with an internal multi-tooth profile and SIT drive . AW is used as an abbreviation for the size specification . Screws with an Assy profile can be screwed in with Torx tools if necessary. The reverse is not the case.
HexStix
For sizes T15 to T50, the Phillips Screw Company offers a compatible system called the HexStix Stable Drive System . These drives / drives have the designations H15 to H50. The advantage of HexStix over Torx is a reduced risk of the tool slipping off the screw, even without a magnetic holder.
Stardrive
The company Synthes Medical uses a modification of Torx under the name Stardrive for implants . Stardrive is partially compatible with Torx.
See also
Web links
Remarks
- ↑ In the classic hexagonal profile, only the partial areas near the edges have a small radial directional component. There are high radial forces that place heavy demands on the tool and screw: z. As an open-end wrench bend and the edges on the screw head "shave".
Individual evidence
- ↑ Register number: 930954. German Patent and Trademark Office , accessed on August 22, 2016 .
- ↑ Register number: 2012008. German Patent and Trademark Office, accessed on August 22, 2016 .
- ↑ Global Brand Database. WIPO , accessed on January 15, 2020 (English, enter "TORX" in the text field and click on "search").
- ↑ Torx Drive System - Patents & Trademarks. Acument, accessed August 22, 2016 .
- ↑ Camcar LLC. Bloomberg LP , accessed August 22, 2016 .
- ↑ FAQs. Acument, accessed August 22, 2016 .
- ↑ ISO 10664: 2014. ISO , accessed August 22, 2016 .
- ↑ DIN EN ISO 10664, German Institute for Standardization , accessed on August 22, 2016 .
- ↑ Chart of Torx fasteners and tools . Wiha Tools USA. Retrieved January 14, 2012.
- ↑ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj Torx Drive System - Product Standards . Acument, July 20, 2015 ( online [accessed September 22, 2016]).
- ↑ Spax Universal Countersunk Wood Construction Screw contorion.at, accessed February 11, 2018.
- ↑ STIER washer head screw, steel, galvanized, TX contorion.at, accessed February 11, 2018.
- ↑ Patent DE 42 06 222 C 2 (PDF), on depatisnet.dpma.de
- ↑ TORX PARALOBE Drive System , on acument.com
- ↑ Phillips Drive System Innovation in Fastener Technology , on phillips-screw.com, accessed June 19, 2020