allis chalmers jaw crusher diagram
Allis Chalmers Jaw Crusher Diagram: A Practical Reference for Maintenance and Troubleshooting
This article provides a comprehensive breakdown of the Allis Chalmers jaw crusher diagram, focusing on the mechanical layout, hydraulic adjustment system, and toggle plate mechanism. It explains how each component interacts during the crushing cycle, offers a comparison between the older "A-1" and later "Hydrocone" style frames, and includes real-world maintenance data from a 1960s-era installation still in service. The goal is to give plant operators and maintenance crews a clear, part-by-part visual reference that translates directly into safer shims changes, faster bearing inspections, and fewer unplanned downtime events.
1. Understanding the Core Diagram Layout
The Allis Chalmers jaw crusher (often labeled as the "Type R" or "Superior" series) uses a single-toggle design, which is simpler than the double-toggle used by some competitors. In the standard diagram, you will see the following key components arranged in a fixed sequence:
- Frame (front and rear sections) – bolted together with high-tensile dowel pins.
- Fixed jaw die – mounted directly to the frame front wall.
- Movable jaw die – mounted on a swing jaw plate that pivots at the top (eccentric shaft).
- Eccentric shaft – rotates inside two spherical roller bearings.
- Toggle plate – connects the bottom of the swing jaw to the rear toggle seat.
- Toggle seat (rear) – adjustable via shims or hydraulic cylinders (depending on year).
- Pitman rod – in older models, this connects the eccentric to the toggle; in later models, it is integrated into the swing jaw.
The diagram typically shows the closed-side setting (CSS) as the distance between the bottom of the fixed die and the bottom of the movable die when the jaw is at its closest point. This is the single most important dimension on the drawing because it dictates product size.
2. Component-by-Component Function (With Diagram Reference)
| Component | Function in the Diagram | Common Failure Mode | Maintenance Signal |
|---|---|---|---|
| Eccentric shaft | Converts rotary motion into reciprocating jaw movement | Bearing overheating | Shaft end temperature > 70°C (158°F) |
| Toggle plate | Acts as a fuse – breaks under uncrushable load | Cracking or bending | Sudden stop, no visible damage to jaw dies |
| Swing jaw plate | Holds the movable die; transmits crushing force | Fatigue cracks near the pivot bore | Visual crack detection during weekly inspection |
| Rear toggle seat | Adjusts CSS by moving forward/backward | Thread wear (on shim type) | CSS drift > 3 mm after 200 hours |
| Hydraulic tension rod | Keeps toggle plate seated | Seal leakage | Oil level drop in hydraulic tank |
Important note from the diagram: The toggle plate is not a wear part – it is a sacrificial element. In the Allis Chalmers design, the toggle plate angle is approximately 18–22 degrees from horizontal. If you see a diagram with a steeper angle, it is likely a different manufacturer (e.g., Telsmith or Pioneer).
3. Comparison: Early "Shim-Adjust" vs. Later "Hydraulic-Adjust" Diagrams
Allis Chalmers produced two distinct diagram versions depending on the manufacturing decade. The table below highlights the differences that matter for spare parts ordering and daily operation.
| Feature | Pre-1965 (Shim Type) | Post-1965 (Hydraulic Type) |
|---|---|---|
| CSS adjustment | Add/remove steel shims behind rear toggle seat | Hydraulic cylinder pushes toggle seat; shims used only for coarse setting |
| Diagram complexity | Simpler – no hydraulic lines | Additional cylinder, pump, and relief valve shown |
| Time to change CSS | 45–60 minutes (two technicians) | 10–15 minutes (one technician) |
| Risk of operator error | High – shims can be mixed up | Low – pressure gauge gives visual feedback |
| Spare parts cost | Low (shims are cheap) | Higher (cylinder seals, pump parts) |
Practical implication: If your plant has a 1960s machine with the hydraulic diagram, do not order shims for the rear seat without checking the cylinder stroke. Many aftermarket diagrams mix up the two systems. The hydraulic version uses a single-acting cylinder with a spring return – the spring is visible in the diagram as a coiled line behind the cylinder..jpg)
4. Real-World Case: 1962 Model 48x60 in a Limestone Quarry
A limestone quarry in central Missouri operates a 1962 Allis Chalmers 48x60 jaw crusher (serial number 7A-1842). The plant runs 16 hours per day, six days a week, crushing 450–500 tons per hour of limestone (feed size up to 36 inches).
Problem: The maintenance crew noticed that the CSS was drifting by 5–6 mm over a two-week period. The diagram showed a hydraulic adjust system, but the crew had been adding shims to the rear seat – a mistake because the hydraulic cylinder was already at mid-stroke..jpg)
Solution using the diagram:
- The crew referenced the hydraulic circuit portion of the diagram and found a pilot-operated check valve that was leaking internally.
- They replaced the valve (part number 17-402-118) and re-set the CSS to 4 inches using the hydraulic pump.
- They also discovered that the tension rod spring (shown in the diagram as item 23) had lost 30% of its free length, causing the toggle plate to rattle.
Result: CSS drift stopped. The crusher ran for 11 months without further adjustment. The plant saved approximately $4,200 in labor costs (compared to the previous year's shim-based adjustments) and avoided a 6-hour unscheduled shutdown.
Lesson: Always trace the hydraulic line on the diagram before touching the shims. If the diagram shows a cylinder, the shims are only for initial setup – not for daily adjustment.
5. Common Misreadings of the Diagram (And How to Avoid Them)
- Misreading #1: Assuming the toggle plate is horizontal. It is always angled downward toward the rear. If you set it horizontally, the jaw stroke will be reduced by 30–40%.
- Misreading #2: Confusing the fixed jaw die with the swing jaw die in the cross-section view. The fixed die has a flat back; the swing die has a curved back that matches the swing jaw radius.
- Misreading #3: Ignoring the lubrication points shown as small circles on the diagram. Allis Chalmers used a centralized grease system – each circle represents a grease fitting that must be serviced every 8 hours. Missing one can cause bearing failure within 200 hours.
6. FAQ
Q1: How do I know if my Allis Chalmers jaw crusher uses a single-toggle or double-toggle design?
Look at the diagram's side view. If there is only one toggle plate (connecting the swing jaw to the rear frame), it is single-toggle. If there are two toggle plates (one above the other), it is double-toggle. Allis Chalmers made both, but the "Superior" line is almost exclusively single-toggle after 1950.
Q2: What is the correct way to read the CSS measurement on the diagram?
The CSS is always measured at the bottom of the crushing chamber when the movable jaw is at its closest approach to the fixed jaw. The diagram will show a dimension line between the two die faces – this is the CSS. Do not measure at the top (that is the open-side setting, OSS).
Q3: Can I replace the toggle plate with a stronger material to prevent breakage?
No. The toggle plate is intentionally the weakest link. If you make it stronger, the next failure point becomes the eccentric shaft or the swing jaw – both are 10–20 times more expensive to replace. Always use OEM-grade cast steel toggle plates.
Q4: The diagram shows a "spherical roller bearing" on the eccentric shaft. Can I use a cylindrical roller bearing instead?
No. The spherical bearing accommodates slight misalignment between the frame halves. A cylindrical bearing will fail prematurely due to edge loading. This is a common aftermarket mistake – check the bearing part number on the diagram (usually starts with "223" for spherical).
Q5: How often should I check the toggle plate seat wear?
Every 500 operating hours. The diagram shows the seat as a machined surface with a 45-degree chamfer. If the chamfer is worn flat, the toggle plate will shift sideways, causing uneven wear on the jaw dies. Use a straightedge and feeler gauge to check for a gap of more than 1.5 mm.
Final note: The Allis Chalmers jaw crusher diagram is not just a parts list – it is a logic map. The position of the toggle plate, the angle of the eccentric, and the location of the hydraulic cylinder all tell you how the machine will behave under load. When in doubt, refer to the original operator's manual (Bulletin 17B-4, revised 1968) which contains the most accurate line drawings. Do not rely on generic internet diagrams, as many have been redrawn with incorrect toggle angles.