US3554332A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vehicle brakes
Assignee: Girling Ltd
•
Filing: 1968-03-18
•
Granted: 1971-01-12
•
Expires: 1988-03-18
Abstract
Abstract The invention is concerned with several principal constructional features of internal shoe drum brakes, these principal features being combined in the brake of FIGS. 3 to 6 of the drawings.
Inventors
- 👤 Anthony William Harrison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:05
CPC Classifications
F; F16; F16D; F16D65/00; F16D65/38; F16D65/40; F16D65/52; F16D65/56; F16D65/561; F16D65/563; F16D51/00; F16D51/16; F16D51/18; F16D51/20; F16D51/22; F16D51/24; F16D65/02; F16D65/04; F16D65/08; F16D65/09; F16D65/091
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
201 words
An internal shoe drum brake comprising a pair of expansible brake shoes, shoe return spring means for retracting said shoes, power actuated service brake means for expanding said shoes, a strut of adjustable length which transmits manually applied loads between said shoes, said service brake means being operable to relieve said strut of load, said strut comprising a pair of relatively rotatable members screw threaded together, and pawl and ratchet means for effecting relative rotation of said members to length said strut in response to excess travel of said shoes upon actuation of said service brake means, said pawl and ratchet means being effective only when said strut is relieved of load as aforesaid, said pawl and ratchet means comprising a pawl, a ratchet wheel fast with one of said rotatable members of said strut, and including pawl spring means constantly biassing said pawl in a sense to effect adjustment of said strut, said pawl spring means applying to said pawl a force intermediate that required to effect relative rotation of said members when said strut is loaded by said shoe return spring means and that required when said strut is relieved of load by actuation of said service brake means.
Claim 2
Dependent Claim
201 words
An internal shoe drum brake comprising a pair of expansible brake shoes, shoe return spring means for retracting said shoes, power actuated service brake means for expanding said shoes, a strut of adjustable length which transmits manually applied loads between said shoes, said service brake means being operable to relieve said strut of load, said strut comprising a pair of relatively rotatable members screw threaded together, and pawl and ratchet means for effecting relative rotation of said members to length said strut in response to excess travel of said shoes upon actuation of said service brake means, said pawl and ratchet means being effective only when said strut is relieved of load as aforesaid, said pawl and ratchet means comprising a pawl, a ratchet wheel fast with one of said rotatable members of said strut, and including pawl spring means constantly biassing said pawl in a sense to effect adjustment of said strut, said pawl spring means applying to said pawl a force intermediate that required to effect relative rotation of said members when said strut is loaded by said shoe return spring means and that required when said strut is relieved of load by actuation of said service brake means.
Claim 3
Dependent Claim
47 words
A brake as claimed in claim 1, wherein said pawl spring means comprises a spring arm fast with said pawl, and means coupling said arm to one of said shoes in such a manner that the spring force applied to said pawl is increased upon brake actuation.
Claim 4
Dependent Claim
52 words
A brake as claimed in claim 2, comprising a brake applying lever forming part of said auxiliary brake means, a pivotal connection between said lever and one said brake shoe, said strut acting between said lever and the other said brake shoe, and pivotal connection means mounting said pawl on said lever.
Claim 5
Dependent Claim
138 words
In an internal shoe drum brake comprising a rigid back plate carrying a pair of expansible brake shoes, shoe return spring means for retracting said shoes, power actuated service brake means for expanding said shoes, and manually actuated auxiliary brake means for expanding said shoes, said auxiliary brake means comprising an actuating lever connected to one shoe and a strut for transmitting auxiliary actuating forces from said lever to the other said shoe, the improvement which comprises: means mounting said lever for movement about an axis transverse to the axis of the brake; and a third order lever having one end pivotally connected to said back plate and the other end operatively connected to said lever and engaging said strut intermediate the ends of said third order lever for transmitting forces from said actuating lever to said strut.
Claim 6
Dependent Claim
138 words
In an internal shoe drum brake comprising a rigid back plate carrying a pair of expansible brake shoes, shoe return spring means for retracting said shoes, power actuated service brake means for expanding said shoes, and manually actuated auxiliary brake means for expanding said shoes, said auxiliary brake means comprising an actuating lever connected to one shoe and a strut for transmitting auxiliary actuating forces from said lever to the other said shoe, the improvement which comprises: means mounting said lever for movement about an axis transverse to the axis of the brake; and a third order lever having one end pivotally connected to said back plate and the other end operatively connected to said lever and engaging said strut intermediate the ends of said third order lever for transmitting forces from said actuating lever to said strut.
Claim 7
Dependent Claim
56 words
The improved brake of claim 1, including means mounting said third order lever substantially parallel with said back plate, said mounting means including an articulated connection between one end of said third order lever and said backplate and means constraining the other end of said lever to move in a plane substantially parallel with said backplate.
Claim 8
Dependent Claim
57 words
The improved brake of claim 4, including a movable abutment having a normal position in which it is engageable by said actuating lever to limit return movement of said actuating lever under the action of said shoe return spring means, said abutment being selectively movable from said position to permit further return movement of said actuating lever.
Claim 9
Dependent Claim
67 words
The improved hand brake of claim 5 wherein said actuating lever is directly mounted on the third order lever for rotation about the axis thereof, said actuating lever extending through said back plate to the side thereof remote from said third order lever, said actuating lever being rotatable about its axis of rotation in response to an actuating force applied thereto substantially perpendicular to said back plate.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-01-11 | 1974-07-13 | 1975-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-11 | 1978-07-13 | 1979-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-11 | 1982-07-13 | 1983-01-12 | $7700.00 | Window Closed / Lapsed |