Follow the eccentric, pitman and toggle links that move a jaw toward a fixed crushing surface. This Blake-pattern illustration lets you compare jaw settings, constrained stroke and cycle timing for one assumed linkage geometry.
Stone Crusher Interactive Calculator
Explore direct geometry for the Hiscox/Blake cam-link-toggle jaw arrangement. The calculator reports settings and ratios, not capacity or product grading.
Equation Used
- Entered throw uses the same proportional scale as the disclosed schematic link lengths.
- Gape and CSS are minimum tooth-tip surface clearances over the cycle at the marked top and discharge heights; the fixed jaw is immutable.
- No capacity, motor power, wear, strength, feed acceptance or product-size guarantee is inferred.
The jaw stroke comes from the illustrated link dimensions. Use the settings to explore motion; they do not establish throughput, product grading or machine capacity.
From Shaft Rotation to Jaw Motion
Hiscox movement 1233, printed page 304, describes the Blake pattern as a shaft-driven cam acting through a vertical connecting link and a toggle joint.
In this illustration, the eccentric pin moves the pitman. The grounded toggle constrains one joint, while the jaw toggle drives a rigid jaw about its upper pivot. The fixed jaw remains stationary as the discharge clearance opens and closes.
The assumed pitman is 44 in long, the ground toggle 20 in, the moving jaw 60 in and the jaw toggle 24 in. Those are this drawing's dimensions, not manufacturer specifications or dimensions supplied by the historical description.
What You Can Compare
Use the animation to identify the drive chain and compare eccentric throw with jaw travel. Set gape and closed-side clearance to see their different locations, then compare an entered feed size with the closed-side setting.
A real crusher selection also needs material characteristics, capacity data, feed distribution, loading and machine specifications. This geometry tool does not calculate those quantities or supply operating and maintenance procedures.
Settings and Cycle Timing
Feed/CSS ratio = F/CSS
Cycle period = 60/N
CSS is the minimum tooth-tip surface clearance at the defined discharge height. Δx is the moving face's horizontal travel there over a complete eccentric revolution. OSS is the resulting maximum clearance. F is entered feed size and N is eccentric speed in RPM.
The calculator sweeps the constrained linkage through 720 angular samples to obtain Δx. It is not simply twice eccentric throw because the pitman, toggles, jaw pivot and measurement height determine the motion.
Feed/CSS is a geometric comparison. It does not guarantee that feed is accepted, broken or discharged at a particular particle size.
Worked Schematic Example
With 1 in eccentric throw, 5 in CSS, 30 in entered feed size and 180 RPM, this assumed linkage gives:
- Constrained surface stroke: approximately 2.52 in.
- Open-side setting: 5 + 2.52 = approximately 7.52 in.
- Feed/CSS ratio: 30/5 = 6.
- Eccentric period: 60/180 = approximately 0.333 s.
The stroke value applies to the fixed schematic dimensions above. Changing the real link lengths, pivots or tooth geometry changes the result. No tonnage, motor rating or product grading follows from these four numbers.
What Each Input Changes
| Input | Role in this tool |
|---|---|
| Gape | Sets the illustrated minimum top opening; it is distinct from the discharge setting. |
| Closed-side setting | Sets minimum discharge clearance and the denominator of Feed/CSS. |
| Eccentric throw | Changes the solved pitman, toggle and jaw motion, hence the calculated surface stroke. |
| Feed size | Changes the geometric Feed/CSS comparison, without simulating rock fracture. |
| Eccentric speed | Changes cycle timing, without calculating crushing force or power. |
The picture and results omit rock contact, crushing forces, wear, flywheel energy, structural stress and overload protection. Actual settings and operating limits must come from the specific machine documentation.
Frequently Asked Questions
Why is the jaw stroke different from twice the eccentric throw?
Throw describes the driving eccentric. The pitman, toggles and pivoted jaw transform that motion; stroke is measured at a defined height on the moving crushing face.
Does Feed/CSS predict the final particle size?
No. It compares two entered dimensions and does not simulate fracture, feed acceptance or product grading.
Why does changing gape not change the numerical stroke?
The stroke calculation uses the fixed schematic linkage and eccentric throw. Gape sets the illustrated top opening rather than changing those link lengths.
Are the assumed link lengths historical dimensions?
No. They define this proportional schematic. The cited historical description identifies the mechanism but does not provide these dimensions.
Can this calculate tonnes per hour or motor power?
No. It contains a geometric linkage calculation and timing conversion, with no capacity or power model.
Does the related wet-grinder video show this jaw mechanism?
No. It illustrates a different stone-working arrangement. The interactive drawing on this page shows the jaw-and-toggle mechanism.
References
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