CA1175253A - Torque limiting transmission apparatus - Google Patents
Torque limiting transmission apparatusInfo
- Publication number
- CA1175253A CA1175253A CA000388925A CA388925A CA1175253A CA 1175253 A CA1175253 A CA 1175253A CA 000388925 A CA000388925 A CA 000388925A CA 388925 A CA388925 A CA 388925A CA 1175253 A CA1175253 A CA 1175253A
- Authority
- CA
- Canada
- Prior art keywords
- torque
- torque means
- relation
- coupling apparatus
- coupling
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Mechanical Operated Clutches (AREA)
Abstract
TORQUE LIMITING TRANSMISSION APPARATUS
ABSTRACT OF THE DISCLOSURE
A torque limiting coupling is provided to permit relative rotational slip between an input member and an output member. The coupling incorporates a plurality of torque transmitting members in an annular arrangement comprising cantilever springs having one end secured to one of the coupling members, with the opposite end of the spring entered within a respective recess of the other coupling member, in torque transmitting relation therewith.
In the event that the applied torque exceeds a predetermined value, each of the torque transmitting cantilever springs deflects to the extent that it withdraws from the recess, permitting relative rotation between the coupling members. Selective profiling of the sides of the recesses limits wearing contact thereof with the spring members. In addition the arrangement is provided in embodiments suited for coupling shafts in torque transmitting relation permitting angular misalignment between the shafts.
ABSTRACT OF THE DISCLOSURE
A torque limiting coupling is provided to permit relative rotational slip between an input member and an output member. The coupling incorporates a plurality of torque transmitting members in an annular arrangement comprising cantilever springs having one end secured to one of the coupling members, with the opposite end of the spring entered within a respective recess of the other coupling member, in torque transmitting relation therewith.
In the event that the applied torque exceeds a predetermined value, each of the torque transmitting cantilever springs deflects to the extent that it withdraws from the recess, permitting relative rotation between the coupling members. Selective profiling of the sides of the recesses limits wearing contact thereof with the spring members. In addition the arrangement is provided in embodiments suited for coupling shafts in torque transmitting relation permitting angular misalignment between the shafts.
Description
I 1 7~53 ~ 1 - 1382 P/2 CA
l~R~UE LIMITI~G TRANSI~ISSION APPARATUS
This invention is directed to a torque limiting coupling for l~miting the torque transmitted between a rotary input n~mber and a rotary output ~m~er by permitting lost ~otiQn between the members when a predetermined value of torque load is exceeded, m e provision of ~orque limited ccuplings is well known, having a wide range of applications. ~ny such prior arrangement ccmprise complex structures haYing intricate componentsr nany of small size, and mostly of a high cost characteristic, ~is has resulted in high cost couplings, thereby limiting their application. Furthermore, owing to the general complexity of design of nost prior art arrangements, they do not lend themselves to a philosophy of low cost, rapid replacement of the torque transmitting elements, upon the occurence of wear.
The present invention provides a torque limiting coupling apparatus having first and second rotatable torque means, one torque n~a~s camprising a torque input, the other torque means comprising a torque output, bearing ~eans inter-connecting the one tor~le ~ns and the other torque n~ans to permit relat~e rotati~on therebet~en, a pluralit~ of cantilever spring means æcure~ to a one torque r~3ms and extending in ~ )7~253
l~R~UE LIMITI~G TRANSI~ISSION APPARATUS
This invention is directed to a torque limiting coupling for l~miting the torque transmitted between a rotary input n~mber and a rotary output ~m~er by permitting lost ~otiQn between the members when a predetermined value of torque load is exceeded, m e provision of ~orque limited ccuplings is well known, having a wide range of applications. ~ny such prior arrangement ccmprise complex structures haYing intricate componentsr nany of small size, and mostly of a high cost characteristic, ~is has resulted in high cost couplings, thereby limiting their application. Furthermore, owing to the general complexity of design of nost prior art arrangements, they do not lend themselves to a philosophy of low cost, rapid replacement of the torque transmitting elements, upon the occurence of wear.
The present invention provides a torque limiting coupling apparatus having first and second rotatable torque means, one torque n~a~s camprising a torque input, the other torque means comprising a torque output, bearing ~eans inter-connecting the one tor~le ~ns and the other torque n~ans to permit relat~e rotati~on therebet~en, a pluralit~ of cantilever spring means æcure~ to a one torque r~3ms and extending in ~ )7~253
- 2 - 1382 P/2 CA
deflectable contact~ng relat~on with the other torque means;
a pluralit~ of recesses in the other torque means to receive the portions of the spring n~ans in en~aging relation therewith to transmit torque from one torque means to the other torque ~ans, the spring means ~eing deflecta~le out of torque transmitting relation with the recesses ~nder predetermuned operating conditions, to permit relative rotation between the first and the second torque means.
The cantilever spring n~ns each generally comprises an elongated kar or rod, generally having a re tangular sectlon, with a profiled head portion to fit within slots provided in an annular housing portion of the input member, the remote ends of the spring means extending within the recesses of the output ~mber, in driving en~age~ent.
The arrangement is suited for drive trains on assembly lines being subject to ja~ming or stalled stops, also typewriter uses, including ribbon and paper feeds. In the case of large motors having non-uniform torque outputs, the coupling can even out t.orque variations.
The selection of high impact plastic material for the kars or rods, as torque transmitting n~nbers provides a number of unobvious advantages, which include; closely coIItrolled engineering characteristics of size and elastic ncdulus; significant hysteresis characteristic; selective frlctional characteristic; re~dily molded or extr~ded he~d sect~on for secur~ng within coupling~ a~oidance of galling ~ ~75253 _ 3 ~ 1382 p/2 CA
or fretting between ~rking surfaces, to n~me but the more evident benefits It is contenplated that the coupling nay be selectively prov~ded with desired ones o the following characteristics, predeterm~ned friction coupling when operating in the overdriven n~de~ operation as a free wheel ~herein t~e driven n~m~er can rotate at a ~igher speed than the driving n~m~er in su~stantially ~nrestricted relation or ~ith a desired frict~onal drag T~e present invent~on lends itself to c~uplings operating in a non-aligned condition, as a so-called universal joint.
.
Figure 1 is an end view of partial section of a first e~cdiment of the invention for coupling two shafts;
Figure 2 is a diametrical cross section at 2-2 of Figure l;
Figure 3 is a diametrical cross section of a further embodiment for a peripheral drive arrangementî
Figure 4 is a cross section detail of an alternatlve torsion spring embodiment, and Fi~ure 5 ~s a dlamet~cal cross sectional vie~
of a plvotal c~upling.
1 1752~3 - 4 ~ 1382 P/2 CA
Referring to the embodiment illustrated in Figures 1 a~d 2, a coupling lO includes a first torque m~ans cc~pricing a hous~ng 12, having a boss 14 with a bore 16 therein and a keyway 18~ to recelve a power transmitting shaft (not shown~ in keyed relation therein, ~ second torque means 20 is mounted by bearing 22 ,in the f~rst housing 12.
m e second torque means 20 has a bore 21 and a ~eyway 24 to receive a power transmitting shaft (not shown) in keyed relation therein~
An annMlar array of torque transmitting elements comprising cantilever springs 26 are mounted in profiled slots 28 of the hcusing 12, the slots being in ccmmunication with an out-side face of t~e housing. The radlally inner ends 29 of the springs 26 extend within recesses 30 of the second torque m~ans 20.
The slots 28 are relieved at 32 in order to facilitate the bending of the springs 26 by avoidance of a point load concentration. Whilst being illustrated as a symmetrical arrangement,it will be understood that by providing the relief 32 on only one side of the springs 26, the apparatus would become "handed'~, and possess torque transmission characteristics that deFend upon the direction of ro~ation of the driYe, ~ cover plate 34 secured by capærews 35 to the hcusing 12 close~ slots 28 where these com~unicate with the out-side face of the ~ousing so as to prcv~de access to the slots ;~
I
1 17~253 ~ 5 ~ 1382 P/2 CA
or a rapid replacem,ent of springs 26. Pre~erably recesses 30 are also in com~unication with t~e same face of housing 12 to facil~tate ~lrther the replacement of spr~ngs 26, ~eferring now to the embodhrent of Figure 3, a couplulg 40 ha~ a first torque ~3ans 42 ~aunted concentricly with a second torque means 44 by way of a ball bearing race 46.
The radially outer torque ~ans 42 has crenellations 43 in the form of gear teeth or splines on the outer periphery t~ereof whereby it is adapted to provide a direct drive connection to a w~rk piece, for exampl.e.
The radially inner torque means 44 has a bore 48 therethrough to receive a shaft, (not shown~ with keyways 49 to provide a torque transfer conneCtiQn therewith, An annular assem~ly of cantilever springs 56 is arranged on each side of the axis of symmetry of the coupling 40, Removeable covers 54 provide access for the replacement of the springs 56, illustrated in Figure 4 as ~aving a T-section, the cross bars 57 of which slide wi-thin suitable T-section slots orm~d in outer torque means 42 so as to anchor the springs thereto with the cross bars in radial alignment.
The Figure 5 embcdiment comprises a coupling 60 with first torque n~ans 62 including a boss 64 having a bore 66 therein to receive a power transmitting shaft (not shown~ in inserted relation t~erein~
~ ) 7525 3 The second torque n~ans 70 includes boss 71 mounted by sp~erical bearing 72 on the first torque means 62.
m e second torque~neans 70 i5 provided wlth curved recesses 78 extending parallel wit~ t~e curvature of the spherical be3ring 72. The radially inner ends of springs 76 fit wtthin t~e recesses 78, Misalignment of the shafts, producing ~isalignment between bosses 64 and 71, which is accommodated by the bearing 72 results in relati~fe displacem~nt of the springs 76 along the arc of contact with the curved recesses 78, thereby maintaining a constancy of torque ~omen~ arm acting on the springs 76, In such an arrangement a spherical or an elliptiical or like surface can,be used for the universal bearing, according to the desired acceptable degree of non-alignment. In the case of a spherical bearing such as Tbrrington (~M) spherical bearing up to about 14~ of a misalignment may be accomm~dated.
deflectable contact~ng relat~on with the other torque means;
a pluralit~ of recesses in the other torque means to receive the portions of the spring n~ans in en~aging relation therewith to transmit torque from one torque means to the other torque ~ans, the spring means ~eing deflecta~le out of torque transmitting relation with the recesses ~nder predetermuned operating conditions, to permit relative rotation between the first and the second torque means.
The cantilever spring n~ns each generally comprises an elongated kar or rod, generally having a re tangular sectlon, with a profiled head portion to fit within slots provided in an annular housing portion of the input member, the remote ends of the spring means extending within the recesses of the output ~mber, in driving en~age~ent.
The arrangement is suited for drive trains on assembly lines being subject to ja~ming or stalled stops, also typewriter uses, including ribbon and paper feeds. In the case of large motors having non-uniform torque outputs, the coupling can even out t.orque variations.
The selection of high impact plastic material for the kars or rods, as torque transmitting n~nbers provides a number of unobvious advantages, which include; closely coIItrolled engineering characteristics of size and elastic ncdulus; significant hysteresis characteristic; selective frlctional characteristic; re~dily molded or extr~ded he~d sect~on for secur~ng within coupling~ a~oidance of galling ~ ~75253 _ 3 ~ 1382 p/2 CA
or fretting between ~rking surfaces, to n~me but the more evident benefits It is contenplated that the coupling nay be selectively prov~ded with desired ones o the following characteristics, predeterm~ned friction coupling when operating in the overdriven n~de~ operation as a free wheel ~herein t~e driven n~m~er can rotate at a ~igher speed than the driving n~m~er in su~stantially ~nrestricted relation or ~ith a desired frict~onal drag T~e present invent~on lends itself to c~uplings operating in a non-aligned condition, as a so-called universal joint.
.
Figure 1 is an end view of partial section of a first e~cdiment of the invention for coupling two shafts;
Figure 2 is a diametrical cross section at 2-2 of Figure l;
Figure 3 is a diametrical cross section of a further embodiment for a peripheral drive arrangementî
Figure 4 is a cross section detail of an alternatlve torsion spring embodiment, and Fi~ure 5 ~s a dlamet~cal cross sectional vie~
of a plvotal c~upling.
1 1752~3 - 4 ~ 1382 P/2 CA
Referring to the embodiment illustrated in Figures 1 a~d 2, a coupling lO includes a first torque m~ans cc~pricing a hous~ng 12, having a boss 14 with a bore 16 therein and a keyway 18~ to recelve a power transmitting shaft (not shown~ in keyed relation therein, ~ second torque means 20 is mounted by bearing 22 ,in the f~rst housing 12.
m e second torque means 20 has a bore 21 and a ~eyway 24 to receive a power transmitting shaft (not shown) in keyed relation therein~
An annMlar array of torque transmitting elements comprising cantilever springs 26 are mounted in profiled slots 28 of the hcusing 12, the slots being in ccmmunication with an out-side face of t~e housing. The radlally inner ends 29 of the springs 26 extend within recesses 30 of the second torque m~ans 20.
The slots 28 are relieved at 32 in order to facilitate the bending of the springs 26 by avoidance of a point load concentration. Whilst being illustrated as a symmetrical arrangement,it will be understood that by providing the relief 32 on only one side of the springs 26, the apparatus would become "handed'~, and possess torque transmission characteristics that deFend upon the direction of ro~ation of the driYe, ~ cover plate 34 secured by capærews 35 to the hcusing 12 close~ slots 28 where these com~unicate with the out-side face of the ~ousing so as to prcv~de access to the slots ;~
I
1 17~253 ~ 5 ~ 1382 P/2 CA
or a rapid replacem,ent of springs 26. Pre~erably recesses 30 are also in com~unication with t~e same face of housing 12 to facil~tate ~lrther the replacement of spr~ngs 26, ~eferring now to the embodhrent of Figure 3, a couplulg 40 ha~ a first torque ~3ans 42 ~aunted concentricly with a second torque means 44 by way of a ball bearing race 46.
The radially outer torque ~ans 42 has crenellations 43 in the form of gear teeth or splines on the outer periphery t~ereof whereby it is adapted to provide a direct drive connection to a w~rk piece, for exampl.e.
The radially inner torque means 44 has a bore 48 therethrough to receive a shaft, (not shown~ with keyways 49 to provide a torque transfer conneCtiQn therewith, An annular assem~ly of cantilever springs 56 is arranged on each side of the axis of symmetry of the coupling 40, Removeable covers 54 provide access for the replacement of the springs 56, illustrated in Figure 4 as ~aving a T-section, the cross bars 57 of which slide wi-thin suitable T-section slots orm~d in outer torque means 42 so as to anchor the springs thereto with the cross bars in radial alignment.
The Figure 5 embcdiment comprises a coupling 60 with first torque n~ans 62 including a boss 64 having a bore 66 therein to receive a power transmitting shaft (not shown~ in inserted relation t~erein~
~ ) 7525 3 The second torque n~ans 70 includes boss 71 mounted by sp~erical bearing 72 on the first torque means 62.
m e second torque~neans 70 i5 provided wlth curved recesses 78 extending parallel wit~ t~e curvature of the spherical be3ring 72. The radially inner ends of springs 76 fit wtthin t~e recesses 78, Misalignment of the shafts, producing ~isalignment between bosses 64 and 71, which is accommodated by the bearing 72 results in relati~fe displacem~nt of the springs 76 along the arc of contact with the curved recesses 78, thereby maintaining a constancy of torque ~omen~ arm acting on the springs 76, In such an arrangement a spherical or an elliptiical or like surface can,be used for the universal bearing, according to the desired acceptable degree of non-alignment. In the case of a spherical bearing such as Tbrrington (~M) spherical bearing up to about 14~ of a misalignment may be accomm~dated.
Claims (11)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A torque limiting coupling apparatus having first and second rotatable torque means, one torque means comprising a torque input, the other torque means comprising a torque output, bearing means interconnecting said one torque means and the other torque means to permit relative rotation there-between; a plurality of cantilever spring means secured to one said torque means and extending in deflectable contacting relation with the other said torque means; a plurality of recesses in said other torque means to receive portions of said spring means in engaging relation therewith to transmit torque from one torque means to the other torque means, said spring means being deflectable out of torque transmitting relation with said recesses under predetermined operating conditions, to permit relative rotation between said first and said second torque means.
2. The coupling apparatus of Claim 1, said cantilever spring means each having a rod-like portion having one end thereof secured to said one torque means, to extend in cantilevered relation therefrom and position the other end of said spring means within a said recess of said other torque means.
3, The coupling apparatus of Claim 2, said cantilever spring means including an enlarged head portion of predetermined cross-sectional shape, said one torque means having slots each of cross-sectional shape to receive a said head portion in secured relation therein.
4. The coupling apparatus of Claim 3 wherein said slots communicate with an outside face of said one torque means,
5. The coupling apparatus of Claim 3, said enlarged head portions including oppositely extending side bars forming a T-section, said slots of said one torque means receiving outer portions of said side bars in close fitting secured relation therein in axial alignment,
6. The coupling apparatus of Claim 1, wherein said cantilever spring means are positioned radially outwardly relative to said other torque means, in inwardly extending relation theretoward.
7. The coupling apparatus of Claim 4,5 or 6, wherein said one torque means includes an outer housing, said other torque means comprises an inner housing and said annular bearing means comprises a ball bearing connecting said one torque means in axially secured relation relative said other torque means.
8. The coupling apparatus of Claim 4,5 or 6, wherein said bearing means includes curved mating surfaces to permit axial misalignment between said first and said second torque means, said recesses in said other torque means having buttress portions thereof correspondingly curved with said mating surfaces, to maintain substantially constant contact relation between said cantilever spring means and said other torque means for a predetermined range of said misalignment.
9. The coupling apparatus of Claim 1,2 or 3 wherein said slots are slots formed with at least one relieved edge portion to provide transverse support to said cantilever spring intermediate its ends when in a deflected condition.
10. The coupling apparatus of Claim 1,2 or 3, one said torque means having an opening therein to receive a shaft in secured relation, the other said torque means having an outer periphery adapted to transmit a torque load therethrough, said apparatus including a first plurality and a second plurality of cantilever spring means in axially spaced relation, having said bearing means located therebetween.
11. The coupling apparatus of Claim 1,2 or 3 wherein said plurality of recesses of said other torque means each includes at least one profiled side wall to provide predetermined contact with a side portion of the respective said cantilever spring, to limit wear therebetween when in a slipping mode.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US22223081A | 1981-01-02 | 1981-01-02 | |
| US222,230 | 1981-01-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1175253A true CA1175253A (en) | 1984-10-02 |
Family
ID=22831404
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000388925A Expired CA1175253A (en) | 1981-01-02 | 1981-10-28 | Torque limiting transmission apparatus |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1175253A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113048171A (en) * | 2020-12-30 | 2021-06-29 | 山东省科学院海洋仪器仪表研究所 | Novel bidirectional self-locking transmission device |
-
1981
- 1981-10-28 CA CA000388925A patent/CA1175253A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113048171A (en) * | 2020-12-30 | 2021-06-29 | 山东省科学院海洋仪器仪表研究所 | Novel bidirectional self-locking transmission device |
| CN113048171B (en) * | 2020-12-30 | 2022-06-14 | 山东省科学院海洋仪器仪表研究所 | Bidirectional self-locking transmission device |
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Legal Events
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| MKEC | Expiry (correction) | ||
| MKEX | Expiry |