Cam operated disc brake

A disc brake assembly comprising a frame including a caliper and brake pads carried thereby in laterally spaced relation to receive a disc therebetween. An actuator including first and second plunger members located for relative lateral displacement to effect displacement of the pads relatively toward one another, thereby to brake the disc and a lever extending between the plunger members with one of the members having a convex nose received in a first wedging bearing formed in the lever. The lever being pivotably mounted about a pivot on the frame for wedging movement between the members to shift and effect relative displacement of the members to brake the disc.

BACKGROUND OF THE INVENTION 
This invention relates generally to brakes, and more particularly concerns 
disc brakes characterized by extreme simplicity, compactness, and high 
strength. 
While many and varied disc brakes have been proposed and constructed in the 
past, none of which I am aware possess the unusual advantages in 
construction, mode of operation and results as are now afforded by the 
present invention. These include simple, mechanical actuation; simple 
adjustment for brake pad wear; self-adjustment relative to the rotating 
disc as by tongue and groove sliding interfit as being a channel shaped 
mount and caliper stiffening portion of the brake frame; integration in a 
simple manner as between two frame parts which define a caliper to carry 
the pads, a sub-section stiffener for the caliper, and a hollow 
sub-section to receive plungers and a lever. 
SUMMARY OF THE INVENTION 
The invention is basically embodied in the following combination: 
(A) A FRAME INCLUDING A CALIPER, AND BRAKE PADS CARRIED THEREBY IN 
LATERALLY SED RELATION TO RECEIVE A DISC THEREBETWEEN, 
(B) FIRST AND SECOND MEMBERS LOCATED FOR RELATIVE LATERAL DISPLACEMENT TO 
EFFECT DISPLACEMENT OF THE PADS RELATIVELY TOWARD ONE ANOTHER, THEREBY TO 
BRAKE THE DISC, 
(C) A T EXTENDING BETWEEN SAID MEMBERS, ONE OF THE MEMBERS COMPRISING A 
PLUNGER HAVING A CONVEX NOSE RECEIVED IN A FIRST CONCAVE BEARING FORMED BY 
SAID T, AND 
(D) MEANS ON THE FRAME SUPPORTING SAID T FOR WEDGING MOVEMENT BETWEEN 
SAID MEMBERS TENDING TO SHIFT SAID BEARING FOR EFFECTING SAID RELATIVE 
DISPLACEMENT OF THE MEMBERS TO BRAKE THE DISC. 
As will appear, one or both members may be defined by plungers each of 
which has a convex nose received in and against a concave bearing. The two 
bearings may be defined by a lever pivoted to the frame so as to wedgingly 
displace one plunger axially relative to the other so as to effect 
braking; further, the plunger furthest from the pads may be adjustable in 
a very simple manner so as to shift the lever and other plunger toward the 
pads, thereby to compensate for pad wear. 
The frame also has the simple, rugged, high strength, compact construction 
as referred to above. Also, a simple, channel-shaped frame mount is 
provided. 
These and other objects and advantages of the invention, as well as the 
details of an illustrative embodiment will be more fully understood from 
the following description and drawings, in which:

DETAILED DESCRIPTION 
The disc brake assembly 10 of FIGS. 1 and 2 includes a frame 11 consisting 
of complementary sections 11a and 11b. In end elevation the sections have 
inverse delta outline configuration, the upper widest apart portions 11c 
and 11d defining horizontally parallel slots 12 and 13. The latter are 
laterally spaced apart and extend lengthwise transversely to slidably and 
lossely receive transversely extending guides formed by a mount. The 
guides may advantageously be defined by inwardly extending tangs 14 on the 
channel shaped mount 15, as seen in FIG. 7. After the mount is suitably 
attached to support structure, as indicated by bolts 16 attached to plate 
17, the frame is guided to slide transversely relative to a rotating disc 
18, whereby brake pads may adjust to engage opposite sides of the disc. As 
shown in FIG. 1, the laterally spaced pads 19 and 20 are carried by the 
lower caliper portion of the frame sections 11a and 11b. That caliper 
portion is further identified as defining the recesses 21 and 22 in which 
the pads are received. 
The frame also includes a first hollow sub-section 11b' formed by section 
11b and located laterally of the caliper portion as referred to. 
Sub-section 11b' is typically rectangular and includes walls 24-27 as 
shown, and defining an interior hollow or chamber 28. The frame also 
includes a second hollow sub-section located in upwardly offset relation 
to a lateral horizontal axis 44, as shown, to stiffen the lower caliper 
portion. In this regard, note walls 31 and 32 of section 11a projecting 
toward and endwise abutting walls 33 and 34 of section 11b, thereby to 
form sub-section 11e with interior hollow 35. Wall 32 is notched at 32a to 
pass the tip portion of disc 18. Accordingly, a lightweight, stiff, 
compact, heavy duty frame is provided. Sections 11a and 11b may be 
attached as by parallel, transverse, through bolts 37 and 38. 
In accordance with an important aspect of the invention, first and second 
members are located for relative lateral displacement to effect 
displacement of the pads 19 and 20 relatively toward one another, thereby 
to brake the disc. In the example, such members may take the form as 
indicated at 39 and 40. One of the members, such as memeber 39 for 
example, may comprise a plunger having a convex nose 39a. The latter is 
received in a first concave bearing 42 formed by a part 41 extending 
between the members 39 and 40, whereby the part 41 is movable between 
these two members to shift the bearing 42 for effecting relative 
displacement of the member and consequent braking of the disc. Part 41 may 
advantageously comprise a lever supported by means on the frame, as for 
example a pivot 43 offset from a lateral axis 44 defined by plunger. Pivot 
43 defines the lever fulcrum, and force may be applied to the lever, as by 
link 45 at the opposite side of axis 44, and with mechanical advantage, to 
displace the bearing 42 with consequent wedging movement and action, as 
described. Pivot 43 also allows movement of the lever bearing toward the 
pads, as will be further referred to in connection with compensation for 
pad wear. 
The other member 40 may also, with advantage, define a second and laterally 
extending plunger, as shown. It may be adjustable toward (and away) from 
the lever to compensate for brake pad wear, and may have threaded interfit 
at 50 with the wall 25. Thus, when lock nut 51 on the plunger 40 is 
loosened to disengage wall 25, the plunger may be rotated as by a tool 
interfitting end slot 40b, to advance the plunger 40 toward plunger 39, 
i.e. deflecting the lever and plunger 39 to advance pad relatively toward 
disc 18. At the same time, the frame 11 may freely shift transversely on 
the guide tangs 14. Thereafter, nut 51 may be tightened against wall 25. 
The nose 40a of the second plunger 40 may also be convex and received in a 
second concave bearing 53 formed by the part of lever 41, axially 
oppositely from bearing 42. As a result, when the lever is pivoted, the 
two bearing surfaces 42 and 53 cooperate to increase the travel of the 
plunger 39, and decrease the necessary lever pivoting. Also, due to the 
bearing and nose relationships, less friction is developed. Further, 
plunger 39 may rotate slightly about axis 44, as accommodated by annular 
bearing 70 in wall 24, in response to lever actuation, whereby different 
portions of the nose are exposed to wear, extending nose life. 
In this regard, the convex nose 39a has circular cross sections in planes 
normal to axis 44, and such planes have circular cross sections with the 
concave bearing 42, when that bearing and the plunger extend coaxially; 
similarly, the convex nose 40a has circular cross sections in planes 
normal to axis 44, and such planes have circular cross sections with the 
concave bearing 53 when that bearing and the plunger 40 extend coaxially. 
Note in FIG. 6 that the pads 19 and 20 have peripheral circular segment 
configuration, with centers 60 offset by dimension "d" from the axis 44. 
For example, recess 22 to closely receive pad 20 has a chordal flat 61, 
which interrupts the circular configuration (with center at 60) of that 
recess. Accordingly, the pads do not tend to rotate when engaging the 
rotating disc 18. Metal plate 64 fits loosely in the recess 22. 
Note in FIG. 7 that the arms 72 of mount 15 are angled with upward taper 
.alpha. to block upward riding of the frame ears 73, whereby clearance 
remains at 74 between the top of the frame and the mount. Greater strength 
is also thereby provided.